%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2004-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(qlc_pt).
%%% Purpose: Implements the qlc Parse Transform.
-export([parse_transform/2, transform_from_evaluator/2,
transform_expression/2]).
-include_lib("stdlib/include/ms_transform.hrl").
-define(APIMOD, qlc).
-define(Q, q).
%% Also in qlc.erl.
-define(QLC_Q(L1, L2, L3, L4, LC, Os),
{call,L1,{remote,L2,{atom,L3,?APIMOD},{atom,L4,?Q}},[LC | Os]}).
-define(IMP_Q(L1, L2, LC, Os), {call,L,{atom,L2,?Q},[LC | Os]}).
%% Also in qlc.erl.
-record(qlc_lc, % qlc:q/1,2, a query handle
{lc,
opt % #qlc_opt
}).
-record(state, {imp,
maxargs,
records,
xwarnings = [],
intro_vars,
node_info}).
%-define(debug, true).
-ifdef(debug).
-define(DEBUG(S, A), io:format(S, A)).
-else.
-define(DEBUG(S, A), ok).
-endif.
%% erl_eval cannot interpret funs with more than 20 arguments:
-define(EVAL_MAX_NUM_OF_ARGS, 20).
%% Currently the compiler can handle at most 255 arguments.
-define(COMPILE_MAX_NUM_OF_ARGS, 250).
-define(QLC_FILE, qlc_current_file).
%%%
%%% Exported functions
%%%
-spec(parse_transform(Forms, Options) -> Forms2 when
Forms :: [erl_parse:abstract_form() | erl_parse:form_info()],
Forms2 :: [erl_parse:abstract_form() | erl_parse:form_info()],
Options :: [Option],
Option :: type_checker | compile:option()).
parse_transform(Forms0, Options) ->
?DEBUG("qlc Parse Transform~n", []),
Imported = is_qlc_q_imported(Forms0),
{Forms, FormsNoShadows, State} = initiate(Forms0, Imported),
NodeInfo = State#state.node_info,
try
case called_from_type_checker(Options) of
true ->
%% The returned value should conform to the types, but
%% need not evaluate to anything meaningful.
L = anno0(),
{tuple,_,Fs0} = abstr(#qlc_lc{}, L),
F = fun(_Id, LC, A) ->
Init = simple(L, 'V', LC, L),
{{tuple,L,set_field(#qlc_lc.lc, Fs0, Init)}, A}
end,
{Forms1,ok} = qlc_mapfold(F, ok, Forms, State),
Forms1;
false ->
case
compile_messages(Forms, FormsNoShadows, Options, State)
of
{[],Warnings} ->
?DEBUG("node info1 ~p~n",
[lists:sort(ets:tab2list(NodeInfo))]),
{NewForms, State1} =
transform(FormsNoShadows, State),
ExtraWs = State1#state.xwarnings,
{[],WForms} = no_duplicates(NewForms, [], Warnings,
ExtraWs, Options),
(restore_locations(WForms, State) ++
restore_anno(NewForms, NodeInfo));
{Errors,Warnings} ->
?DEBUG("node info2 ~p~n",
[lists:sort(ets:tab2list(NodeInfo))]),
{EForms,WForms} = no_duplicates(FormsNoShadows, Errors,
Warnings, [],
Options),
restore_locations(EForms ++ WForms, State) ++ Forms0
end
end
after
true = ets:delete(NodeInfo)
end.
-spec(transform_from_evaluator(LC, Bs) -> Return when
LC :: erl_parse:abstract_expr(),
Bs :: erl_eval:binding_struct(),
Return :: {ok, erl_parse:abstract_expr()}
| {not_ok, {error, module(), Reason :: term()}}).
transform_from_evaluator(LC, Bindings) ->
?DEBUG("qlc Parse Transform (Evaluator Version)~n", []),
transform_expression(LC, Bindings, false).
-spec(transform_expression(LC, Bs) -> Return when
LC :: erl_parse:abstract_expr(),
Bs :: erl_eval:binding_struct(),
Return :: {ok, erl_parse:abstract_expr()}
| {not_ok, [{error, Reason :: term()}]}).
transform_expression(LC, Bindings) ->
transform_expression(LC, Bindings, true).
%%%
%%% Local functions
%%%
called_from_type_checker(Options) ->
lists:member(type_checker, Options).
transform_expression(LC, Bs0, WithLintErrors) ->
L = anno1(),
As = [{var,L,V} || {V,_Val} <- Bs0],
Ar = length(As),
F = {function,L,bar,Ar,[{clause,L,As,[],[?QLC_Q(L, L, L, L, LC, [])]}]},
Forms0 = [{attribute,L,file,{"foo",L}},
{attribute,L,module,foo}, F],
{Forms, FormsNoShadows, State} = initiate(Forms0, false),
NodeInfo = State#state.node_info,
Options = [],
try compile_messages(Forms, FormsNoShadows, Options, State) of
{Errors0,_Warnings} ->
case restore_locations(Errors0, State) of
[] ->
{NewForms,_State1} = transform(FormsNoShadows, State),
NewForms1 = restore_anno(NewForms, NodeInfo),
{function,L,bar,Ar,[{clause,L,As,[],[NF]}]} =
lists:last(NewForms1),
{ok,NF};
Errors when WithLintErrors ->
{not_ok,mforms(error, Errors)};
Errors ->
[{error,Reason} | _] = mforms(error, Errors),
{not_ok, {error, ?APIMOD, Reason}}
end
after
true = ets:delete(NodeInfo)
end.
-ifdef(DEBUG).
-define(ILIM, 0).
-else.
-define(ILIM, 255).
-endif.
initiate(Forms0, Imported) ->
NodeInfo = ets:new(?APIMOD, []),
true = ets:insert(NodeInfo, {var_n, ?ILIM}),
exclude_integers_from_unique_line_numbers(Forms0, NodeInfo),
?DEBUG("node info0 ~p~n",
[lists:sort(ets:tab2list(NodeInfo))]),
State0 = #state{imp = Imported,
maxargs = ?EVAL_MAX_NUM_OF_ARGS,
records = record_attributes(Forms0),
node_info = NodeInfo},
Forms = save_anno(Forms0, NodeInfo),
FormsNoShadows = no_shadows(Forms, State0),
IntroVars = intro_variables(FormsNoShadows, State0),
State = State0#state{intro_vars = IntroVars},
{Forms, FormsNoShadows, State}.
%% Make sure restore_locations() does not confuse integers with (the
%% unique) line numbers.
exclude_integers_from_unique_line_numbers(Forms, NodeInfo) ->
Integers = find_integers(Forms),
lists:foreach(fun(I) -> ets:insert(NodeInfo, {I}) end, Integers).
find_integers(Forms) ->
F = fun(A) ->
Fs1 = map_anno(fun(_) -> A end, Forms),
ordsets:from_list(integers(Fs1, []))
end,
ordsets:to_list(ordsets:intersection(F(anno0()), F(anno1()))).
integers([E | Es], L) ->
integers(Es, integers(E, L));
integers(T, L) when is_tuple(T) ->
integers(tuple_to_list(T), L);
integers(I, L) when is_integer(I), I > ?ILIM ->
[I | L];
integers(_, L) ->
L.
-define(I(I), {integer, L, I}).
-define(A(A), {atom, L, A}).
-define(V(V), {var, L, V}).
-define(ABST_NO_MORE, {nil, L}).
-define(ABST_MORE(Obj, Cont), {cons, L, Obj, Cont}).
%% Qualifier identifier.
%% The first one encountered in a QLC has no=1.
-record(qid, {lcid,no}).
mforms(Tag, L) ->
lists:sort([{Tag,M} || {_File,Ms} <- L, M <- Ms]).
%% Avoid duplicated lint warnings and lint errors. Care has been taken
%% not to introduce unused variables in the transformed code.
%%
no_duplicates(Forms, Errors, Warnings0, ExtraWarnings0, Options) ->
%% Some mistakes such as "{X} =:= {}" are found by strong
%% validation as well as by qlc. Prefer the warnings from qlc:
%% The Compiler and qlc do not agree on the location of errors.
%% For now, qlc's messages about failing patterns and filters
%% are ignored.
ExtraWarnings = [W || W={_File,[{_,qlc,Tag}]} <-
ExtraWarnings0,
not lists:member(Tag, [nomatch_pattern,nomatch_filter])],
Warnings1 = mforms(Warnings0) --
([{File,[{L,v3_core,nomatch}]} ||
{File,[{L,qlc,M}]} <- mforms(ExtraWarnings),
lists:member(M, [nomatch_pattern,nomatch_filter])]
++
[{File,[{L,sys_core_fold,nomatch_guard}]} ||
{File,[{L,qlc,M}]} <- mforms(ExtraWarnings),
M =:= nomatch_filter]),
Warnings = Warnings1 ++ ExtraWarnings,
{Es1,Ws1} = compile_forms(Forms, Options),
Es = mforms(Errors) -- mforms(Es1),
Ws = mforms(Warnings) -- mforms(Ws1),
{mforms2(error, Es),mforms2(warning, Ws)}.
mforms(L) ->
lists:sort([{File,[M]} || {File,Ms} <- L, M <- Ms]).
mforms2(Tag, L) ->
Line = anno0(),
ML = lists:flatmap(fun({File,Ms}) ->
[[{attribute,Line,file,{File,0}}, {Tag,M}] ||
M <- Ms]
end, lists:sort(L)),
lists:flatten(lists:sort(ML)).
restore_locations([T | Ts], State) ->
[restore_locations(T, State) | restore_locations(Ts, State)];
restore_locations(T, State) when is_tuple(T) ->
list_to_tuple(restore_locations(tuple_to_list(T), State));
restore_locations(I, State) when I > ?ILIM ->
restore_loc(I, State);
restore_locations(T, _State) ->
T.
is_qlc_q_imported(Forms) ->
[[] || {attribute,_,import,{?APIMOD,FAs}} <- Forms, {?Q,1} <- FAs] =/= [].
record_attributes(Forms) ->
[A || A = {attribute, _, record, _D} <- Forms].
%% Get the compile errors and warnings for the QLC as well as messages
%% for introduced variables used in list expressions and messages for
%% badargs. Since the QLCs will be replaced by some terms, the
%% compiler cannot find the errors and warnings after the parse
%% transformation.
%%
compile_messages(Forms, FormsNoShadows, Options, State) ->
%% The qlc module cannot handle binary generators.
BGenF = fun(_QId,{b_generate,Line,_P,_LE}=BGen, GA, A) ->
M = {loc(Line),?APIMOD,binary_generator},
{BGen,[{get(?QLC_FILE),[M]}|GA],A};
(_QId, Q, GA, A) ->
{Q,GA,A}
end,
{_,BGens} = qual_fold(BGenF, [], [], Forms, State),
GenForm = used_genvar_check(FormsNoShadows, State),
?DEBUG("GenForm = ~ts~n", [catch erl_pp:form(GenForm)]),
{GEs,_} = compile_forms([GenForm], Options),
UsedGenVarMsgs = used_genvar_messages(GEs, State),
NodeInfo = State#state.node_info,
WarnFun = fun(_Id, LC, A) -> {lc_nodes(LC, NodeInfo), A} end,
{WForms,ok} = qlc_mapfold(WarnFun, ok, Forms, State),
{Es,Ws} = compile_forms(WForms, Options),
LcEs = lc_messages(Es, NodeInfo),
LcWs = lc_messages(Ws, NodeInfo),
Errors = badarg(Forms, State) ++ UsedGenVarMsgs++LcEs++BGens,
Warnings = LcWs,
{Errors,Warnings}.
badarg(Forms, State) ->
F = fun(_Id, {lc,_L,_E,_Qs}=LC, Es) ->
{LC,Es};
(Id, A, Es) ->
E = {get_lcid_line(Id),?APIMOD,not_a_query_list_comprehension},
{A,[{get(?QLC_FILE), [E]} | Es]}
end,
{_,E0} = qlc_mapfold(F, [], Forms, State),
E0.
lc_nodes(E, NodeInfo) ->
map_anno(fun(Anno) ->
N = erl_anno:line(Anno),
[{N, Data}] = ets:lookup(NodeInfo, N),
NData = Data#{inside_lc => true},
true = ets:insert(NodeInfo, {N, NData}),
Anno
end, E).
used_genvar_messages(MsL, S) ->
[{File,[{Loc,?APIMOD,{used_generator_variable,V}}]}
|| {_, Ms} <- MsL,
{XLoc,erl_lint,{unbound_var,_}} <- Ms,
{Loc,File,V} <- [genvar_pos(XLoc, S)]].
lc_messages(MsL, NodeInfo) ->
[{File,[{Loc,Mod,T} || {Loc,Mod,T} <- Ms, lc_loc(Loc, NodeInfo)]} ||
{File,Ms} <- MsL].
lc_loc(N, NodeInfo) ->
case ets:lookup(NodeInfo, N) of
[{N, #{inside_lc := true}}] ->
true;
[{N, _}] ->
false
end.
genvar_pos(Location, S) ->
case ets:lookup(S#state.node_info, Location) of
[{Location, #{genvar_pos := Pos}}] ->
Pos;
[] ->
Location
end.
%% -> [{Qid,[variable()]}].
%%
%% For each qualifier the introduced variables are found. The
%% variables introduced in filters are very much like the variables
%% introduced in generator patterns. If no variables are introduced in
%% a qualifier, [variable()] is empty.
%%
%% Generator: all variables occurring in the pattern are introduced
%% variables.
%% Filter: all variables bound inside the filter are introduced
%% variables (unless they are unsafe).
%%
intro_variables(FormsNoShadows, State) ->
NodeInfo = State#state.node_info,
Fun = fun(QId, {T,_L,P0,_E0}=Q, {GVs,QIds}, Foo) when T =:= b_generate;
T =:= generate ->
PVs = qlc:var_ufold(fun({var,_,V}) -> {QId,V} end, P0),
{Q,{ordsets:to_list(PVs) ++ GVs,[{QId,[]} | QIds]},Foo};
(QId, Filter0, {GVs,QIds}, Foo) ->
%% The filter F is replaced by begin E, F, E end,
%% where E is an LC expression consisting of a
%% template mentioning all variables occurring in F.
Vs = ordsets:to_list(qlc:vars(Filter0)),
AnyLine = anno0(),
Vars = [{var,AnyLine,V} || V <- Vs],
LC = embed_vars(Vars, AnyLine),
LC1 = intro_anno(LC, before, QId, NodeInfo),
LC2 = intro_anno(LC, 'after', QId, NodeInfo),
Filter = {block,AnyLine,[LC1,Filter0,LC2]},
{Filter,{GVs,[{QId,[]} | QIds]},Foo}
end,
Acc0 = {[],[]},
{FForms,{GenVars,QIds}} =
qual_fold(Fun, Acc0, [], FormsNoShadows, State),
%% Note: the linter messages are the ones we are looking for.
%% If there are no linter messages, the compiler will crash (ignored).
Es0 = compile_errors(FForms),
%% A variable is bound inside the filter if it is not bound before
%% the filter, but it is bound after the filter (obviously).
Before = [{QId,V} ||
{L,erl_lint,{unbound_var,V}} <- Es0,
{_L,{QId,before}} <- ets:lookup(NodeInfo, L)],
After = [{QId,V} ||
{L,erl_lint,{unbound_var,V}} <- Es0,
{_L,{QId,'after'}} <- ets:lookup(NodeInfo, L)],
Unsafe = [{QId,V} ||
{L,erl_lint,{unsafe_var,V,_Where}} <- Es0,
{_L,{QId,'after'}} <- ets:lookup(NodeInfo, L)],
?DEBUG("Before = ~p~n", [Before]),
?DEBUG("After = ~p~n", [After]),
?DEBUG("Unsafe = ~p~n", [Unsafe]),
?DEBUG("Filter ~p~n", [(Before -- After) -- Unsafe]),
IV = (Before -- After) -- Unsafe,
I1 = family(IV ++ GenVars),
sofs:to_external(sofs:family_union(sofs:family(QIds), I1)).
intro_anno(LC, Where, QId, NodeInfo) ->
Data = {QId,Where},
Fun = fun(Anno) ->
Location = erl_anno:location(Anno),
true = ets:insert(NodeInfo, {Location,Data}),
Anno
end,
map_anno(Fun, save_anno(LC, NodeInfo)).
compile_errors(FormsNoShadows) ->
case compile_forms(FormsNoShadows, []) of
{[], _Warnings} ->
[];
{Errors, _Warnings} ->
?DEBUG("got errors ~tp~n", [Errors]),
lists:flatmap(fun({_File,Es}) -> Es end, Errors)
end.
compile_forms(Forms0, Options) ->
Exclude = fun(eof) -> true;
(warning) -> true;
(error) -> true;
(_) -> false
end,
Forms = ([F || F <- Forms0, not Exclude(element(1, F))]
++ [{eof,anno0()}]),
try
case compile:noenv_forms(Forms, compile_options(Options)) of
{ok, _ModName, Ws0} ->
{[], Ws0};
{error, Es0, Ws0} ->
{Es0, Ws0}
end
catch _:_ ->
%% The compiler is not available. Use the linter instead.
case erl_lint:module(Forms, lint_options(Options)) of
{ok, Warnings} ->
{[], Warnings};
{error, Errors, Warnings} ->
{Errors, Warnings}
end
end.
compile_options(Options) ->
No = [report,report_errors,report_warnings,'P','E' | bitstr_options()],
[strong_validation,return | skip_options(No, Options)].
lint_options(Options) ->
skip_options(bitstr_options(), Options).
skip_options(Skip, Options) ->
[O || O <- Options, not lists:member(O, Skip)].
bitstr_options() ->
[binary_comprehension,bitlevel_binaries].
%% In LCs it is possible to use variables introduced in filters and
%% generator patterns in the right hand side of generators (ListExpr),
%% but in QLCs this is not allowed.
%%
%% A brand new function is returned such that there is one expression
%% for each ListExpr. The expression mentions all introduced variables
%% occurring in ListExpr. Running the function through the compiler
%% yields error messages for erroneous use of introduced variables.
%%
used_genvar_check(FormsNoShadows, State) ->
NodeInfo = State#state.node_info,
F = fun(QId, {T, Ln, _P, LE}=Q, {QsIVs0, Exprs0}, IVsSoFar0)
when T =:= b_generate; T =:= generate ->
F = fun(Var) ->
{var, Anno0, OrigVar} =
undo_no_shadows(Var, State),
{var, Anno, _} = NewVar = save_anno(Var, NodeInfo),
Location0 = erl_anno:location(Anno0),
Location = erl_anno:location(Anno),
[{Location, Data}] =
ets:lookup(NodeInfo, Location),
Pos = {Location0,get(?QLC_FILE),OrigVar},
NData = Data#{genvar_pos => Pos},
true = ets:insert(NodeInfo, {Location, NData}),
NewVar
end,
Vs = [Var || {var, _, V}=Var <- qlc:var_fold(F, [], LE),
lists:member(V, IVsSoFar0)],
Exprs = case Vs of
[] -> Exprs0;
_ -> [embed_vars(Vs, Ln) | Exprs0]
end,
{QsIVs,IVsSoFar} = q_intro_vars(QId, QsIVs0, IVsSoFar0),
{Q, {QsIVs, Exprs}, IVsSoFar};
(QId, Filter, {QsIVs0, Exprs}, IVsSoFar0) ->
{QsIVs, IVsSoFar} = q_intro_vars(QId, QsIVs0, IVsSoFar0),
{Filter, {QsIVs, Exprs}, IVsSoFar}
end,
Acc0 = {State#state.intro_vars, [{atom, anno0(), true}]},
{_, {[], Exprs}} = qual_fold(F, Acc0, [], FormsNoShadows, State),
FunctionNames = [Name || {function, _, Name, _, _} <- FormsNoShadows],
UniqueFName = qlc:aux_name(used_genvar, 1, sets:from_list(FunctionNames)),
A = anno0(),
{function,A,UniqueFName,0,[{clause,A,[],[],lists:reverse(Exprs)}]}.
q_intro_vars(QId, [{QId, IVs} | QsIVs], IVsSoFar) -> {QsIVs, IVs ++ IVsSoFar}.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% The transformed code has two major parts: a fun where each
%% qualifier is represented by one or more clauses, and a table where
%% list expressions (the right hand side of generators, LE) are
%% represented by funs (the table is further processed at runtime).
%% The separation into a fun and a table makes it possible to
%% rearrange qualifiers while keeping the speed offered by compiled
%% code, and to run the LEs before evaluation of the QLC (and possibly
%% modify the LEs should that be necessary). Only when doing a fast
%% join are qualifiers rearranged.
%%
%% Extra generators (and clauses) are inserted for possible fast join
%% operations. The list expression for such a generator has the form
%% {join, Op, QualifierNumber1, QualifierNumber2, PatternFilter1,
%% PatternFilter2, PatternConstants1, PatternConstants2} (it is not a
%% fun). Join generators are ignored at runtime unless a fast join is
%% possible, in which case they replace other generators. See also
%% qlc.erl.
%%
%% For each QLC, every filter is given a state number and every
%% generator two state numbers (one for initialization, one for
%% looping over values). State 1 is reserved for the template and
%% state 0 is entered when there are no more values to try, so
%% assuming no rearrangement of the qualifiers has taken place, the
%% first qualifier is given state number 2. For every state except 0,
%% the table tells which state to go to next. By modifying the table,
%% the order of the qualifiers can be altered at runtime.
%%
%% The syntax of the value Val returned from the fun is:
%% Val = [] | [term() | Val] | fun() -> Val
%% Note: the fun must not return a fun if it is to be called by
%% the function outlined below.
%%
%% An outline of the generated fun:
%%
%% fun(0, RL, ...) when is_list(RL) -> % the final state
%% lists:reverse(RL); % eval, all answers collected in a list
%% (0, ...) -> []; % cursor (or fold)
%% (1, RL, ...) when is_list(RL) -> % the template state
%% Fun(<last generator loop state>, [Template | RL], ...);
%% (1, ....) -> % return the object and a continuation
%% [Template | fun() -> Fun(<last generator loop state>, ...)];
%% (2, ...) -> % an sample generator, initialization state
%% Fun(3, ..., <initial value>, ...);
%% (3, ..., [Pattern | Val], ...) -> % looping over values (a list)
%% Fun(<next qualifier state>, ..., Val, ...); % arguments are bound
%% (3, ..., [_ | Val], ...) -> % pattern does not match
%% Fun(3, ..., Val, ...);
%% (3, ..., [], ...) ->
%% Fun(<last generator loop state>, ...);
%% (3, ...., F, ...) -> % looping over values (using continuations)
%% case F() of % get the next value by calling a continuation
%% [Pattern | Val] ->
%% Fun(<next qualifier state>..., Val, ...);
%% [_ | Val] ->
%% Fun(3, ..., Val, ...);
%% [] ->
%% Fun(<last generator loop state>, ...);
%% T -> % returned immediately, typically an error tuple
%% T
%% end;
%% (4, ...) -> % a sample filter
%% case Filter of
%% true -> Fun(<next qualifier state>, ...);
%% false -> Fun(<last generator loop state>, ...)
%% end;
%% (5, ...) -> % a filter so simple that it could be used as a guard
%% if
%% Guard -> Fun(<next qualifier state>, ...);
%% true -> Fun(<last generator loop state>, ...)
%% end
%%
%% <last generator loop state> means state 0 if there is no last
%% generator. <initial value> is the evaluated list expression
%% (evaluated once only). Among the arguments indicated by ellipses
%% are all variables introduced in patterns and filters.
%%
%% transform/2 replaces each QLC (call to qlc:q/1) with a qlc_lc
%% record. The general case is that calling the fun stored in the 'lc'
%% field returns {qlc_v1, QFun, CodeF, Qdata, QOpt} such that: QFun is
%% the above mentioned fun; CodeF is a fun returning the original code
%% for the template, every pattern, and every filter; Qdata is the
%% above mentioned table; QOpt is a property list implemented as a fun
%% of one argument - an atom - which returns information about such
%% things as constant columns, match specifications, &c.
%% There is one special case when calling the fun stored in the 'lc'
%% field returns something else:
%% - If the QLC has the form [Var || Var <- LE] and there are no
%% options to qlc:q/2, a tuple {simple_v1, P, LEf, Line} is returned.
%% The objects returned are the objects returned by the generator
%% (calling LEf returns the objects generated by LE).
transform(FormsNoShadows, State) ->
_ = erlang:system_flag(backtrace_depth, 500),
IntroVars = State#state.intro_vars,
AllVars = sets:from_list(ordsets:to_list(qlc:vars(FormsNoShadows))),
?DEBUG("AllVars = ~p~n", [sets:to_list(AllVars)]),
F1 = fun(QId, {generate,_,P,LE}, Foo, {GoI,SI}) ->
{{QId,GoI,SI,{gen,P,LE}},Foo,{GoI + 3, SI + 2}};
(QId, F, Foo, {GoI,SI}) ->
{{QId,GoI,SI,{fil,F}},Foo,{GoI + 2,SI + 1}}
end,
TemplS = qlc:template_state(),
GoState = {TemplS + 1, TemplS + 1},
{ModifiedForms1,_} =
qual_fold(F1, [], GoState, FormsNoShadows, State),
%% This is for info/2. QLCs in filters and the template are
%% translated before the expression itself is translated. info/2
%% must not display the result of the translation, but the source
%% code.
{_,Source0} = qual_fold(fun(_QId, {generate,_,_P,_E}=Q, Dict, Foo) ->
{Q,Dict,Foo};
(QId, F, Dict, Foo) ->
{F,dict:store(QId, F, Dict),Foo}
end, dict:new(), [], FormsNoShadows, State),
{_,Source} = qlc_mapfold(fun(Id, {lc,_L,E,_Qs}=LC, Dict) ->
{LC,dict:store(Id, E, Dict)}
end, Source0, FormsNoShadows, State),
%% Unused variables introduced in filters are not optimized away.
F2 = fun(Id, {lc,_L,E,Qs}, {IntroVs0,XWarn0}) ->
LcNo = get_lcid_no(Id),
LcL = get_lcid_line(Id),
[RL,Fun,Go,NGV,S0,RL0,Go0,AT,Err] =
aux_vars(['RL','Fun','Go','C','S0','RL0','Go0','AT','E'],
LcNo, AllVars),
?DEBUG("RL = ~p, Fun = ~p, Go = ~p~n", [RL, Fun, Go]),
{IntroVs, RestIntroVs} = lists:split(length(Qs), IntroVs0),
IntroVs_Qs = lists:zip(IntroVs, Qs),
F = fun({{QId,IVs}, {QId,GoI,SI,{gen,P,LE}}}, AllIVs0) ->
GV = aux_var('C', LcNo, QId#qid.no, 1, AllVars),
GenIVs = [GV | IVs],
{{QId,{GenIVs,{{gen,P,LE,GV},GoI,SI}}},
GenIVs ++ AllIVs0};
({{QId,IVs}, {QId,GoI,SI,{fil,F}}}, AllIVs0) ->
{{QId,{IVs,{{fil,F},GoI,SI}}},
IVs++AllIVs0}
end,
{QCs, AllIVs} = lists:mapfoldl(F, [], IntroVs_Qs),
Dependencies = qualifier_dependencies(Qs, IntroVs),
L = no_compiler_warning(LcL),
{EqColumnConstants, EqualColumnConstants,
ExtraConsts, SizeInfo} =
constants_and_sizes(Qs, E, Dependencies, AllIVs, State),
{JoinInfo, XWarn} =
join_kind(Qs, LcL, AllIVs, Dependencies, State),
%% Not at all sure it is a good idea to try and find
%% failing qualifiers; Dialyzer does it so much better.
%% But there are a few cases where qlc finds more... (r12b).
FWarn = warn_failing_qualifiers(Qs, AllIVs, Dependencies,
State),
JQs = join_quals(JoinInfo, QCs, L, LcNo, ExtraConsts, AllVars),
XQCs = QCs ++ JQs,
Cs0 = clauses(XQCs, RL, Fun, Go, NGV, Err, AllIVs, State),
Template = template(E, RL, Fun, Go, AT, L, AllIVs, State),
Fin = final(RL, AllIVs, L, State),
FunC = {'fun',L,{clauses,Fin ++ Template ++ Cs0}},
As0 = pack_args(abst_vars([S0, RL0, Fun, Go0
| replace(AllIVs, AllIVs, nil)],
L), L, State),
AsW = abst_vars([S0, RL0, Go0], L),
FunW = {'fun',L,{clauses,[{clause,L,AsW,[],
[{match,L,{var,L,Fun},FunC},
{call,L,{var,L,Fun},As0}]}]}},
{ok, OrigE0} = dict:find(Id, Source),
OrigE = undo_no_shadows(OrigE0, State),
QCode = qcode(OrigE, XQCs, Source, L, State),
Qdata = qdata(XQCs, L),
TemplateInfo =
template_columns(Qs, E, AllIVs, Dependencies, State),
%% ExtraConsts should be used by match_spec_quals.
MSQs = match_spec_quals(E, Dependencies, Qs, State),
Opt = opt_info(TemplateInfo, SizeInfo, JoinInfo, MSQs, L,
EqColumnConstants, EqualColumnConstants),
LCTuple =
case qlc_kind(OrigE, Qs, State) of
qlc ->
{tuple,L,[?A(qlc_v1),FunW,QCode,Qdata,Opt]};
{simple, PL, LE, V} ->
Init = closure(LE, L),
simple(L, V, Init, PL)
end,
LCFun = {'fun',L,{clauses,[{clause,L,[],[],[LCTuple]}]}},
{tuple,_,Fs0} = abstr(#qlc_lc{}, L),
Fs = set_field(#qlc_lc.lc, Fs0, LCFun),
{{tuple,L,Fs},{RestIntroVs,FWarn++XWarn++XWarn0}}
end,
{NForms,{[],XW}} = qlc_mapfold(F2, {IntroVars,[]}, ModifiedForms1, State),
display_forms(NForms),
{NForms, State#state{xwarnings = XW}}.
join_kind(Qs, LcL, AllIVs, Dependencies, State) ->
{EqualCols2, EqualColsN} = equal_columns(Qs, AllIVs, Dependencies, State),
{MatchCols2, MatchColsN} = eq_columns(Qs, AllIVs, Dependencies, State),
Tables = lists:usort
([T || {C,_Skip} <- EqualCols2, {T,_} <- C]
++ [T || {C,_Skip} <- EqualCols2, T <- C, is_integer(T)]),
if
EqualColsN =/= []; MatchColsN =/= [] ->
{[],
[{get(?QLC_FILE),[{LcL,?APIMOD,too_complex_join}]}]};
EqualCols2 =:= [], MatchCols2 =:= [] ->
{[], []};
length(Tables) > 2 ->
{[],
[{get(?QLC_FILE),[{LcL,?APIMOD,too_many_joins}]}]};
EqualCols2 =:= MatchCols2 ->
{EqualCols2, []};
true ->
{{EqualCols2, MatchCols2}, []}
end.
qlc_kind(OrigE, Qs, State) ->
{OrigFilterData, OrigGeneratorData} =
qual_data(undo_no_shadows(Qs, State)),
OrigAllFilters = filters_as_one(OrigFilterData),
{_FilterData, GeneratorData} = qual_data(Qs),
case {OrigE, OrigAllFilters, OrigGeneratorData} of
{{var,_,V}, {atom,_,true}, [{_,{gen,{var,PatternL,V},_LE}}]} ->
[{_,{gen,_,LE}}] = GeneratorData,
{simple, PatternL, LE, V}; % V is for info()
_ ->
qlc
end.
%% Finds filters and patterns that cannot match any values at all.
%% Nothing but the patterns and the filters themselves is analyzed.
%% A much weaker analysis than the one of Dialyzer's.
warn_failing_qualifiers(Qualifiers, AllIVs, Dependencies, State) ->
{FilterData, GeneratorData} = qual_data(Qualifiers),
Anon = 1,
BindFun = fun(_Op, Value) -> is_bindable(Value) end,
{PFrame, _PatternVars} =
pattern_frame(GeneratorData, BindFun, Anon, State),
{_, _, Imported} =
filter_info(FilterData, AllIVs, Dependencies, State),
PFrames = frame2frames(PFrame),
{_, Warnings} =
lists:foldl(fun({_QId,{fil,_Filter}}, {[]=Frames,Warnings}) ->
{Frames,Warnings};
({_QId,{fil,Filter}}, {Frames,Warnings}) ->
case filter(reset_anno(Filter), Frames, BindFun,
State, Imported) of
[] ->
{[],
[{get(?QLC_FILE),
[{loc(element(2, Filter)),?APIMOD,
nomatch_filter}]} | Warnings]};
Frames1 ->
{Frames1,Warnings}
end;
({_QId,{gen,Pattern,_}}, {Frames,Warnings}) ->
case pattern(Pattern, Anon, [], BindFun, State) of
{failed, _, _} ->
{Frames,
[{get(?QLC_FILE),
[{loc(element(2, Pattern)),?APIMOD,
nomatch_pattern}]} | Warnings]};
_ ->
{Frames,Warnings}
end
end, {PFrames,[]}, FilterData++GeneratorData),
Warnings.
-define(TNO, 0).
-define(TID, #qid{lcid = template, no = ?TNO}).
opt_info(TemplateInfo, Sizes, JoinInfo, MSQs, L,
EqColumnConstants0, EqualColumnConstants0) ->
SzCls = [{clause,L,[?I(C)],[],[?I(Sz)]} || {C,Sz} <- lists:sort(Sizes)]
++ [{clause,L,[?V('_')],[],[?A(undefined)]}],
S = [{size, {'fun', L, {clauses, SzCls}}}],
J = case JoinInfo of [] -> []; _ -> [{join, abstr(JoinInfo, L)}] end,
%% Superfluous clauses may be emitted:
TCls0 = lists:append(
[[{clause,L,[abstr(Col, L),EqType],[],
[abstr(TemplCols, L)]} ||
{Col,TemplCols} <- TemplateColumns]
|| {EqType, TemplateColumns} <- TemplateInfo]),
TCls = lists:sort(TCls0) ++ [{clause,L,[?V('_'),?V('_')],[],[{nil,L}]}],
T = [{template, {'fun', L, {clauses, TCls}}}],
%% The template may also have a constant function (IdNo = 0).
%% Only constant template columns are interesting.
EqColumnConstants = opt_column_constants(EqColumnConstants0),
CCs = opt_constants(L, EqColumnConstants),
EqC = {constants,{'fun',L,{clauses,CCs}}},
EqualColumnConstants = opt_column_constants(EqualColumnConstants0),
ECCs = opt_constants(L, EqualColumnConstants),
EqualC = {equal_constants,{'fun',L,{clauses,ECCs}}},
C = [EqC | [EqualC || true <- [CCs =/= ECCs]]],
%% Comparisons yield more constant columns than matchings.
ConstCols = [{IdNo,Col} ||
{{IdNo,Col},[_],_FilNs} <- EqualColumnConstants],
ConstColsFamily = family_list(ConstCols),
NSortedCols0 = [{IdNo,hd(lists:seq(1, length(Cols)+1)--Cols)} ||
{IdNo,Cols} <- ConstColsFamily],
NCls = [{clause,L,[?I(IdNo)],[],[?I(N-1)]} ||
{IdNo,N} <- NSortedCols0, N > 0]
++ [{clause,L,[?V('_')],[],[?I(0)]}],
N = [{n_leading_constant_columns,{'fun',L,{clauses,NCls}}}],
ConstCls = [{clause,L,[?I(IdNo)],[],[abstr(Cols,L)]} ||
{IdNo,Cols} <- ConstColsFamily]
++ [{clause,L,[?V('_')],[],[{nil,L}]}],
CC = [{constant_columns,{'fun',L,{clauses,ConstCls}}}],
MSCls = [{clause,L,[?I(G)],[],[{tuple,L,[MS,abstr(Fs,L)]}]} ||
{G,MS,Fs} <- MSQs]
++ [{clause,L,[?V('_')],[],[?A(undefined)]}],
MS = [{match_specs, {'fun',L,{clauses,MSCls}}}],
Cls = [{clause,L,[?A(Tag)],[],[V]} ||
{Tag,V} <- lists:append([J, S, T, C, N, CC, MS])]
++ [{clause,L,[?V('_')],[],[?A(undefined)]}],
{'fun', L, {clauses, Cls}}.
opt_column_constants(ColumnConstants0) ->
[CC || {{IdNo,_Col},Const,_FilNs}=CC <- ColumnConstants0,
(IdNo =/= ?TNO) or (length(Const) =:= 1)].
opt_constants(L, ColumnConstants) ->
Ns = lists:usort([IdNo || {{IdNo,_Col},_Const,_FilNs} <- ColumnConstants]),
[{clause,L,[?I(IdNo)],[],[column_fun(ColumnConstants, IdNo, L)]}
|| IdNo <- Ns]
++ [{clause,L,[?V('_')],[],[?A(no_column_fun)]}].
abstr(Term, Anno) ->
erl_parse:abstract(Term, loc(Anno)).
%% Extra generators are introduced for join.
join_quals(JoinInfo, QCs, L, LcNo, ExtraConstants, AllVars) ->
{LastGoI, LastSI} =
lists:foldl(fun({_QId,{_QIVs,{{fil,_},GoI,SI}}},
{GoI0, _SI0}) when GoI >= GoI0 ->
{GoI + 2, SI + 1};
({_QId,{_QIVs,{{gen,_,_,_},GoI,SI}}},
{GoI0, _SI0}) when GoI >= GoI0 ->
{GoI + 3, SI + 2};
(_, A) ->
A
end, {0, 0}, QCs),
LastQId = lists:max([QId || {QId,{_QIVs,{_Q,_GoI,_SI}}} <- QCs]),
%% Only two tables for the time being.
%% The join generator re-uses the generator variable assigned to
%% the first of the two joined generators. Its introduced variables
%% are the variables introduced by any of the two joined generators.
%% Its abstract code is a pair of the joined generators' patterns.
QNums = case JoinInfo of
{EqualCols, MatchCols} ->
EQs = join_qnums(EqualCols),
MQs = join_qnums(MatchCols),
[{Q1,Q2,'=:='} || {Q1,Q2} <- MQs] ++
[{Q1,Q2,'=='} || {Q1,Q2} <- EQs -- MQs];
EqualCols ->
[{Q1,Q2,'=='} || {Q1,Q2} <- join_qnums(EqualCols)]
end,
LD = [begin
[{QId1,P1,GV1,QIVs1}] =
[{QId,P,GV,QIVs} ||
{QId,{QIVs,{{gen,P,_,GV},_GoI,_SI}}} <- QCs,
QId#qid.no =:= Q1],
[{QId2,P2,QIVs2}] =
[{QId,P,QIVs--[GV]} ||
{QId,{QIVs,{{gen,P,_,GV},_,_}}} <- QCs,
QId#qid.no =:= Q2],
{QId1,Op,P1,GV1,QIVs1++QIVs2,QId2,P2}
end || {Q1, Q2, Op} <- lists:usort(QNums)],
Aux = abst_vars(aux_vars(['F','H','O','C'], LcNo, AllVars), L),
F = fun({QId1,Op,P1,GV1,QIVs,QId2,P2}, {QId,GoI,SI}) ->
AP1 = anon_pattern(P1),
AP2 = anon_pattern(P2),
Cs1 = join_handle_constants(QId1, ExtraConstants),
Cs2 = join_handle_constants(QId2, ExtraConstants),
H1 = join_handle(AP1, L, Aux, Cs1),
H2 = join_handle(AP2, L, Aux, Cs2),
%% Op is not used.
Join = {join,Op,QId1#qid.no,QId2#qid.no,H1,H2,Cs1,Cs2},
G = {NQId=QId#qid{no = QId#qid.no + 1},
{QIVs,{{gen,{cons,L,P1,P2},Join,GV1},GoI,SI}}},
A = {NQId, GoI + 3, SI + 2},
{G, A}
end,
{Qs, _} = lists:mapfoldl(F, {LastQId, LastGoI, LastSI}, LD),
Qs.
join_qnums(Cols) ->
lists:usort([{Q1, Q2} || {[{Q1,_C1}, {Q2,_C2}], _Skip} <- Cols]).
%% Variables occurring only once are replaced by '_'.
anon_pattern(P) ->
MoreThanOnce = lists:usort(occ_vars(P) -- qlc:vars(P)),
{AP, foo} = var_mapfold(fun({var, L, V}, A) ->
case lists:member(V, MoreThanOnce) of
true ->
{{var, L, V}, A};
false ->
{{var, L, '_'}, A}
end
end, foo, P),
AP.
%% Creates a handle that filters the operands of merge join using the
%% pattern. It is important that objects that do not pass the pattern
%% are filtered out because the columns of the pattern are inspected
%% in order to determine if key-sorting the operands can be avoided.
%%
%% No objects will be filtered out if the pattern is just a variable.
join_handle(AP, L, [F, H, O, C], Constants) ->
case {AP, Constants} of
{{var, _, _}, []} ->
{'fun',L,{clauses,[{clause,L,[H],[],[H]}]}};
_ ->
A = anno0(),
G0 = [begin
Call = {call,A,{atom,A,element},[{integer,A,Col},O]},
list2op([{op,A,Op,Con,Call} || {Con,Op} <- Cs], 'or')
end || {Col,Cs} <- Constants],
G = if G0 =:= [] -> G0; true -> [G0] end,
CC1 = {clause,L,[AP],G,[{cons,L,O,closure({call,L,F,[F,C]},L)}]},
CC2 = {clause,L,[?V('_')],[],[{call,L,F,[F,C]}]},
Case = {'case',L,O,[CC1,CC2]},
Cls = [{clause,L,[?V('_'),{nil,L}],[],[{nil,L}]},
{clause,L,[F,{cons,L,O,C}],[],[Case]},
{clause,L,[F,C],[[{call,L,?A(is_function),[C]}]],
[{call,L,F,[F,{call,L,C,[]}]}]},
{clause,L,[?V('_'),C],[],[C]}],
Fun = {'fun', L, {clauses, Cls}},
{'fun',L,{clauses,[{clause,L,[H],[],[{match,L,F,Fun},
closure({call,L,F,[F,H]},
L)]}]}}
end.
join_handle_constants(QId, ExtraConstants) ->
IdNo = QId#qid.no,
case lists:keyfind(IdNo, 1, ExtraConstants) of
{IdNo, ConstOps} ->
ConstOps;
false ->
[]
end.
%%% By the term "imported variable" is meant a variable that is bound
%%% outside (before) the QLC. Perhaps "parameter" would be a more
%%% suitable name.
%% The column fun is to be used when there is a known key column or
%% indices. The argument is a column number and the return value is a
%% list of the values to look up to get all objects needed to evaluate
%% the filter. The order of the objects need not be the same as the
%% order the traverse fun would return them.
column_fun(Columns, QualifierNumber, LcL) ->
A = anno0(),
ColCls0 =
[begin
true = Vs0 =/= [], % at least one value to look up
Vs1 = list2cons(Vs0),
Fils1 = {tuple,A,[{atom,A,FTag},
lists:foldr
(fun(F, Ac) -> {cons,A,{integer,A,F},Ac}
end, {nil,A}, Fils)]},
Tag = case ordsets:to_list(qlc:vars(Vs1)) of
Imp when length(Imp) > 0, % imported vars
length(Vs0) > 1 ->
usort_needed;
_ ->
values
end,
Vs = {tuple,A,[{atom,A,Tag},Vs1,Fils1]},
{clause,A,[erl_parse:abstract(Col)],[],[Vs]}
end ||
{{CIdNo,Col}, Vs0, {FTag,Fils}} <- Columns,
CIdNo =:= QualifierNumber]
++ [{clause,A,[{var,A,'_'}],[],[{atom,A,false}]}],
ColCls = set_anno(ColCls0, LcL),
{'fun', LcL, {clauses, ColCls}}.
%% Tries to find columns of the template that (1) are equal to (or
%% match) or (2) match columns of the patterns of the generators. The
%% results are to be used only for determining which columns are
%% sorted. The template can be handled very much like a generator
%% pattern (the variables are not fresh, though). As in filters calls
%% like element(I, T) are recognized.
%% -> [{EqType,Equal | Match}]
%% Equal = Match = TemplateColumns
%% EqType = abstract code for {_ | '==' | '=:='}
%% TemplateColumns = [{Column,Integers}] % integer is position in template
%% Column = {QualifierNumber,ColumnNumber}} % column is position in pattern
template_columns(Qs0, E0, AllIVs, Dependencies, State) ->
E = expand_expr_records(pre_expand(E0), State),
TemplateAsPattern = template_as_pattern(E),
Qs = [TemplateAsPattern | Qs0],
EqualColumns = equal_columns2(Qs, AllIVs, Dependencies, State),
MatchColumns = eq_columns2(Qs, AllIVs, Dependencies, State),
Equal = template_cols(EqualColumns),
Match = template_cols(MatchColumns),
L = anno0(),
if
Match =:= Equal ->
[{?V('_'), Match}];
true ->
[{?A('=='), Equal}, {?A('=:='), Match}]
end.
equal_columns2(Qualifiers, AllIVs, Dependencies, State) ->
{JI, _Skip} =
join_info(Qualifiers, AllIVs, Dependencies, State,_JoinOp = '=='),
JI.
eq_columns2(Qualifiers, AllIVs, Dependencies, State) ->
{JI, _SKip} =
join_info(Qualifiers, AllIVs, Dependencies, State, _JoinOp = '=:='),
JI.
template_cols(ColumnClasses) ->
lists:sort([{{IdNo,Col}, lists:usort(Cs)} ||
Class <- ColumnClasses,
{IdNo,Col} <- Class,
IdNo =/= ?TNO,
[] =/= (Cs = [C || {?TNO,C} <- Class])]).
template_as_pattern(E) ->
P = simple_template(E),
{?TID,foo,foo,{gen,P,{nil,anno0()}}}.
simple_template({call,L,{remote,_,{atom,_,erlang},{atom,_,element}}=Call,
[{integer,_,I}=A1,A2]}) when I > 0 ->
%% This kludge is known by pattern/5 below.
{call, L, Call, [A1, simple_template(A2)]};
simple_template({var, _, _}=E) ->
E;
simple_template({tuple, L, Es}) ->
{tuple, L, [simple_template(E) || E <- Es]};
simple_template({cons, L, H, T}) ->
{cons, L, simple_template(H), simple_template(T)};
simple_template(E) ->
case catch erl_parse:normalise(E) of
{'EXIT', _} -> unique_var();
_ -> E
end.
%% -> [{QId,[QId']}].
%% Qualifier QId (a filter) uses variables introduced in QId'.
qualifier_dependencies(Qualifiers, IntroVs) ->
Intro = sofs:relation([{IV,QId} || {QId,IVs} <- IntroVs, IV <- IVs]),
{FilterData, _} = qual_data(Qualifiers),
Used = sofs:relation([{QId,UV} ||
{QId,{fil,F}} <- FilterData,
UV <- qlc:vars(F)]),
Depend = sofs:strict_relation(sofs:relative_product(Used, Intro)),
G = sofs:family_to_digraph(sofs:relation_to_family(Depend)),
Dep0 = [{V,digraph_utils:reachable_neighbours([V], G)} ||
V <- digraph:vertices(G)],
true = digraph:delete(G),
FilterIds = sofs:set(filter_ids(Qualifiers)),
Dep1 = sofs:restriction(sofs:family(Dep0), FilterIds),
NoDep = sofs:constant_function(FilterIds, sofs:empty_set()),
sofs:to_external(sofs:family_union(Dep1, NoDep)).
filter_ids(Qualifiers) ->
{FilterData, _} = qual_data(Qualifiers),
[QId || {QId,_} <- FilterData].
%% -> [{QualifierNumber,MatchSpec,[QualifierNumber']}
%% The qualifiers [QualifierNumber'] are filters (F1, ..., Fn) that
%% depend on QualifierNumber (a generator Pattern <- LE) only.
%% MatchSpec is the match specification for [Pattern' || Pattern <- LE,
%% F1, ..., Fn], where Pattern' is Template if all qualifiers can be
%% replaced by one match specification, otherwise a modified Pattern.
match_spec_quals(Template, Dependencies, Qualifiers, State) ->
{FilterData, GeneratorData} = qual_data(Qualifiers),
NoFilterGIds = [GId || {GId,_} <- GeneratorData]
-- lists:flatmap(fun({_,GIds}) -> GIds end, Dependencies),
Filters = filter_list(FilterData, Dependencies, State),
Candidates = [{QId2#qid.no,Pattern,[Filter],F} ||
{QId,[QId2]} <- Dependencies,
{GQId,{gen,Pattern,_}} <- GeneratorData,
GQId =:= QId2,
{FQId,{fil,F}}=Filter <- Filters, % guard filters only
FQId =:= QId]
++ [{GId#qid.no,Pattern,[],{atom,anno0(),true}} ||
{GId,{gen,Pattern,_}} <- GeneratorData,
lists:member(GId, NoFilterGIds)],
E = {nil, anno0()},
GF = [{{GNum,Pattern},Filter} ||
{GNum,Pattern,Filter,F} <- Candidates,
no =/= try_ms(E, Pattern, F, State)],
GFF = sofs:relation_to_family(sofs:relation(GF,
[{gnum_pattern,[filter]}])),
GFFL = sofs:to_external(sofs:family_union(GFF)),
try
[{{GNum,Pattern}, GFilterData}] = GFFL,
true = length(GFilterData) =:= length(FilterData),
[_] = GeneratorData,
AbstrMS = gen_ms(Template, Pattern, GFilterData, State),
%% There is one generator and every filter uses some of the
%% variables introduced by the generator. The whole qlc
%% expressione can be replaced by a match specification.
[{GNum, AbstrMS, all}]
catch _:_ ->
{TemplVar, _} = anon_var({var,anno0(),'_'}, 0),
[one_gen_match_spec(GNum, Pattern, GFilterData, State, TemplVar) ||
{{GNum,Pattern},GFilterData} <- GFFL]
end.
one_gen_match_spec(GNum, Pattern0, GFilterData, State, TemplVar) ->
{E, Pattern} = pattern_as_template(Pattern0, TemplVar),
AbstrMS = gen_ms(E, Pattern, GFilterData, State),
{GNum, AbstrMS, [FId#qid.no || {FId,_} <- GFilterData]}.
gen_ms(E, Pattern, GFilterData, State) ->
{ok, MS, AMS} = try_ms(E, Pattern, filters_as_one(GFilterData), State),
case MS of
[{'$1',[true],['$1']}] ->
{atom, anno0(), no_match_spec};
_ ->
AMS
end.
%% -> {Template, Pattern'}
%% The pattern is accepted by ets:fun2ms/1, that is, =/2 can only
%% occur at top level. Introduce or reuse a top-level variable as
%% template
pattern_as_template({var,_,'_'}, TemplVar) ->
{TemplVar, TemplVar};
pattern_as_template({var,_,_}=V, _TemplVar) ->
{V, V};
pattern_as_template({match,L,E,{var,_,'_'}}, TemplVar) ->
{TemplVar, {match,L,E,TemplVar}};
pattern_as_template({match,L,{var,_,'_'},E}, TemplVar) ->
{TemplVar, {match,L,E,TemplVar}};
pattern_as_template({match,_,_E,{var,_,_}=V}=P, _TemplVar) ->
{V, P};
pattern_as_template({match,_,{var,_,_}=V,_E}=P, _TemplVar) ->
{V, P};
pattern_as_template(E, TemplVar) ->
L = anno0(),
{TemplVar, {match, L, E, TemplVar}}.
%% Tries to find columns which are compared or matched against
%% constant values or other columns. To that end unification is used.
%% A frame is a list of bindings created by unification.
%% Also tries to find the number of columns of patterns.
%% Note that the template is handled more or less as a pattern.
%% -> {ColumnConstants, SizeInfo, ExtraConstants}
%% ColumnConstants = [{Column,[Constant],[FilterNo]}]
%% SizeInfo = [{QualifierNumber,NumberOfColumns}]
%% Column = {QualifierNumber,ColumnNumber}}
%% FilterNo is a filter that can be skipped at runtime provided constants
%% are looked up.
%% ExtraConstants =
%% [{GeneratorNumber,[{ColumnNumber,
%% [{AbstractConstant,AbstractOperator}]}]}]
%% For every generator such that the unification binds value(s) to
%% some column(s), extra constants are returned. These constants are
%% the results of the unification, and do not occur in the pattern of
%% the generator.
constants_and_sizes(Qualifiers0, E, Dependencies, AllIVs, State) ->
TemplateAsPattern = template_as_pattern(E),
Qualifiers = [TemplateAsPattern | Qualifiers0],
{FilterData, GeneratorData} = qual_data(Qualifiers),
{Filter, Anon1, Imported} =
filter_info(FilterData, AllIVs, Dependencies, State),
PatBindFun = fun(_Op, Value) -> is_bindable(Value) end,
{PatternFrame, PatternVars} =
pattern_frame(GeneratorData, PatBindFun, Anon1, State),
PatternFrames = frame2frames(PatternFrame),
FilterFun =
fun(BindFun) ->
filter(Filter, PatternFrames, BindFun, State, Imported)
end,
SzFs = FilterFun(PatBindFun),
SizeInfo = pattern_sizes(PatternVars, SzFs),
SelectorFun = const_selector(Imported),
PatternConstants =
lists:flatten(frames_to_columns(PatternFrames, PatternVars,
deref_pattern(Imported),
SelectorFun, Imported,
'=:=')),
{EqColumnConstants, _EqExtraConsts} =
constants(FilterFun, PatternVars, PatternConstants, PatternFrame,
FilterData, Dependencies, _LookupOp1 = '=:=',
Imported, State),
{EqualColumnConstants, EqualExtraConsts} =
constants(FilterFun, PatternVars, PatternConstants, PatternFrame,
FilterData, Dependencies, _LookupOp2 = '==',
Imported, State),
%% Use compared extra constants only because:
%% - merge join compares terms;
%% - the constants from the matching unification is a subset of the
%% constants from the comparing unification.
%% Using constants from the matching unification would make it
%% possible to skip some (more) objects when joining.
ExtraCon1 =
[{{GId,Col},{Val,Op}} ||
{Consts,Op} <- [{EqualExtraConsts,'=='}],
{{GId,Col},Val} <- Consts],
ExtraConstants =
family_list([{GId, {Col,ValOps}} ||
{{GId,Col},ValOps} <- family_list(ExtraCon1)]),
{EqColumnConstants, EqualColumnConstants, ExtraConstants, SizeInfo}.
constants(FilterFun, PatternVars, PatternConstants, PatternFrame,
FilterData, Dependencies, LookupOp, Imported, State) ->
BindFun = fun(_Op, Value) -> is_bindable(Value) end,
Fs = FilterFun(BindFun),
SelectorFun = const_selector(Imported),
ColumnConstants0 = frames_to_columns(Fs, PatternVars,
deref_lookup(Imported, LookupOp),
SelectorFun, Imported, LookupOp),
ColumnConstants1 = lists:flatten(ColumnConstants0),
ExtraConstants =
[{{GId,Col},Val} ||
{{GId,Col},Vals} <- ColumnConstants1 -- PatternConstants,
GId =/= ?TNO,
Val <- Vals],
ColumnConstants = lu_skip(ColumnConstants1, FilterData, PatternFrame,
PatternVars, Dependencies, State,
Imported, LookupOp),
{ColumnConstants, ExtraConstants}.
%%% ** Comparing Terms **
%%% When comparing the key against a term where some integer (or float
%%% comparing equal to an integer) occurs, one has to be careful if the
%%% table matches keys. One way would be to look up the term both with
%%% the integer and with the float comparing equal to the integer--then
%%% all objects that could possibly be answers are filtered (with
%%% reasonable assumptions). But if integers occur several times in the
%%% term all combinations have to be looked up, and that could be just
%%% too many.
%%% If imported variables occur in the term one could assume at compile
%%% time that they are not integers and check that assumption at
%%% runtime. However, this would probably be bad design since some keys
%%% can be looked up, but others cannot.
%%% However, the current implementation is simple: do not bind a
%%% variable to a term if imported variables or integers occur in the
%%% term.
deref_lookup(Imported, '==') ->
%% Comparing table. Every value can be looked up.
fun(PV, F) -> deref_values(PV, F, Imported) end;
deref_lookup(Imported, '=:=') ->
%% Matching table. Ignore comparisons unless the value is free of
%% integers. See also Comparing Terms.
BFun = fun(DV, Op) ->
Op =:= '=:=' orelse free_of_integers(DV, Imported)
end,
fun(PV, F) -> deref_values(PV, F, BFun, Imported) end.
%% Augment ColConstants with filters that do not need to be run
%% provided that constants are looked up.
%% Does not find all filters that can be removed.
lu_skip(ColConstants, FilterData, PatternFrame, PatternVars,
Dependencies, State, Imported, LookupOp) ->
%% If there is a test that does not compare or match, then the
%% filter cannot be skipped.
FailSelector = fun(_Frame) -> fun(Value) -> {yes, Value} end end,
%% In runtime, constants are looked up and matched against a pattern
%% (the pattern acts like a filter), then the filters are run.
PatternFrames = frame2frames(PatternFrame),
PatternColumns =
lists:flatten(frames_to_columns(PatternFrames, PatternVars,
deref_pattern(Imported), FailSelector,
Imported, LookupOp)),
%% Note: ColFil can contain filters for columns that cannot be
%% looked up. Such (possibly bogus) elements are however not used.
%% Note: one filter at a time is tested; only the pattern is
%% assumed to have been run when the filter is run. Sometimes it
%% would be advantageously to assume some filter(s) occurring
%% before the filter had been run as well
%% (an example: {{X,Y}} <- LE, X =:= 1, Y =:= a).
BindFun = fun(_Op, Value) -> is_bindable(Value) end,
ColFil = [{Column, FId#qid.no} ||
{FId,{fil,Fil}} <-
filter_list(FilterData, Dependencies, State),
[] =/= (SFs = safe_filter(reset_anno(Fil), PatternFrames,
BindFun, State, Imported)),
{GId,PV} <- PatternVars,
[] =/=
(Cols = hd(frames_to_columns(SFs, [{GId, PV}],
deref_lu_skip(LookupOp,
Imported),
const_selector(Imported),
Imported, LookupOp))),
%% The filter must not test more than one column (unless the
%% pattern has already done the test):
%% Note: if the pattern and the filter test the same
%% column, the filter will not be skipped.
%% (an example: {X=1} <- ..., X =:= 1).
length(D = Cols -- PatternColumns) =:= 1,
{{_,Col} = Column, Constants} <- D,
%% Check that the following holds for all frames.
lists:all(
fun(Frame) ->
%% The column is compared/matched against a constant.
%% If there are no more comparisons/matches then
%% the filter can be replaced by the lookup of
%% the constant.
{VarI, FrameI} = unify_column(Frame, PV, Col, BindFun,
Imported),
VarValues = deref_skip(VarI, FrameI, LookupOp, Imported),
{NV, F1} = unify_column(PatternFrame, PV, Col, BindFun,
Imported),
F2 = unify_var_bindings(VarValues, '=:=', NV, F1,
BindFun, Imported, false),
%% F2: the pattern has been matched and the
%% constant has been looked up. If Frame has no
%% more bindings than F2 (modulo unique
%% variables), then the filter can be skipped.
%%
%% Under rare circumstances (for instance:
%% "X =:= 1, X =:= U", U imported; only 1 is looked up),
%% not all constants mentioned in a filter are looked up.
%% The filter can only be skipped if all constants
%% are looked up.
LookedUpConstants =
case lists:keyfind(Column, 1, ColConstants) of
false -> [];
{Column, LUCs} -> LUCs
end,
%% Don't try to handle filters that compare several
%% values equal. See also frames_to_columns().
length(VarValues) =< 1 andalso
(Constants -- LookedUpConstants =:= []) andalso
bindings_is_subset(Frame, F2, Imported)
end, SFs)],
ColFils = family_list(ColFil),
%% The skip tag 'all' means that all filters are covered by the lookup.
%% It does not imply that there is only one generator as is the case
%% for match specifications (see match_spec_quals above).
[{Col, Constants, skip_tag(Col, ColFils, FilterData)} ||
{Col,Constants} <- ColConstants].
deref_skip(E, F, _LookupOp, Imported) ->
deref(E, F, Imported).
deref_lu_skip('==', Imported) ->
%% Comparing table. Cannot skip filters that match integers.
BFun = fun(DV, Op) ->
Op =:= '==' orelse free_of_integers(DV, Imported)
end,
fun(PV, F) -> deref_values(PV, F, BFun, Imported) end;
deref_lu_skip('=:=', Imported) ->
%% Matching table. Skip filters regardless of operator.
fun(PV, F) -> deref_values(PV, F, Imported) end.
equal_columns(Qualifiers, AllIVs, Dependencies, State) ->
{Cs, Skip} =
join_info(Qualifiers, AllIVs, Dependencies, State, _JoinOp = '=='),
join_gens(Cs, Qualifiers, Skip).
eq_columns(Qualifiers, AllIVs, Dependencies, State) ->
{Cs, Skip} =
join_info(Qualifiers, AllIVs, Dependencies, State, _JoinOp = '=:='),
join_gens(Cs, Qualifiers, Skip).
%% -> {TwoGens, ManyGens}
join_gens(Cs0, Qs, Skip) ->
Cs = [family_list(C) || C <- Cs0],
{FD, _GeneratorData} = qual_data(Qs),
{join_gens2(lists:filter(fun(C) -> length(C) =:= 2 end, Cs), FD, Skip),
join_gens2(lists:filter(fun(C) -> length(C) > 2 end, Cs), FD, Skip)}.
join_gens2(Cs0, FilterData, Skip) ->
[{J, skip_tag(case lists:keyfind(J, 1, Skip) of
{J, FilL} ->
FilL;
false ->
[]
end, FilterData)} ||
J <- lists:append([qlc:all_selections(C) || C <- Cs0])].
skip_tag(FilList, FilterData) ->
{if
length(FilterData) =:= length(FilList) ->
all;
true ->
some
end, FilList}.
skip_tag(Col, ColFils, FilterData) ->
case lists:keyfind(Col, 1, ColFils) of
{Col, FilL} ->
Tag = if
length(FilterData) =:= length(FilL) ->
all;
true ->
some
end,
{Tag, FilL};
false ->
{some,[]}
end.
%% Tries to find columns (possibly in the same table) that are equal.
%% If LookupOp is '=:=' then "equal" means that the columns are matched;
%% if LookupOp is '==' then "equal" means that the columns are matched or
%% compared.
%% -> [[{QualifierNumber,ColumnNumber}]] % Eq.classes.
join_info(Qualifiers, AllIVs, Dependencies, State, JoinOp) ->
{FilterData, GeneratorData} = qual_data(Qualifiers),
{Filter, Anon1, Imported} =
filter_info(FilterData, AllIVs, Dependencies, State),
BindFun = fun(_Op, V) -> bind_no_const(V, Imported) end,
{PatternFrame, PatternVars} =
pattern_frame(GeneratorData, BindFun, Anon1, State),
PatternFrames = frame2frames(PatternFrame),
Fs = filter(Filter, PatternFrames, BindFun, State, Imported),
SelectorFun = no_const_selector(Imported),
Cols = frames_to_columns(Fs, PatternVars,
fun(PV1, F) -> deref_join(PV1, F, JoinOp) end,
SelectorFun, Imported, '=:='),
JC = join_classes(Cols),
Skip = join_skip(JC, FilterData, PatternFrame,
PatternVars, Dependencies, State, Imported, JoinOp),
{JC, Skip}.
deref_join(E, Frame, '==') ->
deref_values(E, Frame, _Imp = []);
deref_join(E, Frame, '=:=') ->
%% Matching table. It is possible that some objects read from the
%% other table (the one with the objects to look up) contain
%% integers. By making all variables imported it is ensured that
%% comparisons are kept. See also Comparing Terms.
deref_values(E, Frame, fun(_DV, Op) -> Op =:= '=:=' end, all).
join_classes(Cols0) ->
ColVar = sofs:relation(lists:append(Cols0)),
Cols = sofs:partition(2, ColVar),
[[C || {C,_} <- Cs] || Cs <- sofs:to_external(Cols), length(Cs) > 1].
join_skip(JoinClasses, FilterData, PatternFrame, PatternVars, Dependencies,
State, Imported, JoinOp) ->
PatternFrames = frame2frames(PatternFrame),
ColFil = [{JoinClass,FId#qid.no} ||
[{Q1,C1}, {Q2,C2}]=JoinClass <- JoinClasses,
{GId1, PV1} <- PatternVars,
GId1#qid.no =:= Q1,
{GId2, PV2} <- PatternVars,
GId2#qid.no =:= Q2,
%% Select a filter that depends on the two generators:
{FId,{fil,Fil}} <-
filter_list(FilterData, Dependencies, State),
{value,{_,GIds}} <-
[lists:keysearch(FId, 1, Dependencies)],
GIds =:= lists:sort([GId1,GId2]),
begin
%% Do what the join does:
%% element(C1, G1) JoinOp element(C2, G2).
%% As for lu_skip: sometimes it would be
%% advantageously to assume some filter(s)
%% occurring before the join filter had been run
%% as well.
BindFun = fun(_Op, V) -> is_bindable(V) end,
{V1, JF1} =
unify_column(PatternFrame, PV1, C1, BindFun, Imported),
{V2, JF2} =
unify_column(JF1, PV2, C2, BindFun, Imported),
JF = unify(JoinOp, V1, V2, JF2, BindFun, Imported),
%% "Run" the filter:
SFs = safe_filter(reset_anno(Fil), PatternFrames,
BindFun, State, Imported),
JImp = qlc:vars([SFs, JF]), % kludge
lists:all(fun(Frame) ->
bindings_is_subset(Frame, JF, JImp)
end, SFs) andalso SFs =/= []
end],
family_list(ColFil).
filter_info(FilterData, AllIVs, Dependencies, State) ->
FilterList = filter_list(FilterData, Dependencies, State),
Filter0 = reset_anno(filters_as_one(FilterList)),
Anon0 = 0,
{Filter, Anon1} = anon_var(Filter0, Anon0),
Imported = ordsets:subtract(qlc:vars(Filter), % anonymous too
ordsets:from_list(AllIVs)),
{Filter, Anon1, Imported}.
%% Selects the guard filters. Other filters than guard filters are
%% ignored when trying to find constants and join columns. Note: there
%% must not occur any non-guard filter between a guard filter and the
%% generator(s) the guard filter depends on. The reason is that such a
%% filter could fail for some object(s) excluded by lookup or join. If
%% the failing filter is placed _after_ the guard filter, the failing
%% objects have already been filtered out by the guard filter.
%% Note: guard filters using variables from one generator are allowed
%% to be placed after further generators (the docs states otherwise, but
%% this seems to be common practice).
filter_list(FilterData, Dependencies, State) ->
RDs = State#state.records,
sel_gf(FilterData, 1, Dependencies, RDs, [], []).
sel_gf([], _N, _Deps, _RDs, _Gens, _Gens1) ->
[];
sel_gf([{#qid{no = N}=Id,{fil,F}}=Fil | FData], N, Deps, RDs, Gens, Gens1) ->
case erl_lint:is_guard_test(F, RDs) of
true ->
{Id,GIds} = lists:keyfind(Id, 1, Deps),
case length(GIds) =< 1 of
true ->
case generators_in_scope(GIds, Gens1) of
true ->
[Fil|sel_gf(FData, N+1, Deps, RDs, Gens, Gens1)];
false ->
sel_gf(FData, N + 1, Deps, RDs, [], [])
end;
false ->
case generators_in_scope(GIds, Gens) of
true ->
[Fil | sel_gf(FData, N + 1, Deps, RDs, Gens, [])];
false ->
sel_gf(FData, N + 1, Deps, RDs, [], [])
end
end;
false ->
sel_gf(FData, N + 1, Deps, RDs, [], [])
end;
sel_gf(FData, N, Deps, RDs, Gens, Gens1) ->
sel_gf(FData, N + 1, Deps, RDs, [N | Gens], [N | Gens1]).
generators_in_scope(GenIds, GenNumbers) ->
lists:all(fun(#qid{no=N}) -> lists:member(N, GenNumbers) end, GenIds).
pattern_frame(GeneratorData, BindFun, Anon1, State) ->
Frame0 = [],
{PatternFrame, _Anon2, PatternVars} =
lists:foldl(fun({QId,{gen,Pattern,_}}, {F0,An0,PVs}) ->
{F1, An1, PV} =
pattern(Pattern, An0, F0, BindFun, State),
{F1, An1, [{QId,PV} | PVs]}
end, {Frame0, Anon1, []}, GeneratorData),
{PatternFrame, PatternVars}.
const_selector(Imported) ->
selector(Imported, fun is_const/2).
no_const_selector(Imported) ->
selector(Imported, fun(V, I) -> not is_const(V, I) end).
selector(Imported, TestFun) ->
fun(_Frame) ->
fun(Value) ->
case TestFun(Value, Imported) of
true ->
{yes, Value};
false ->
no
end
end
end.
bind_no_const(Value, Imported) ->
case is_const(Value, Imported) of
true ->
false;
false ->
is_bindable(Value)
end.
%% Tuple tails are variables, never constants.
is_const(Value, Imported) ->
%% is_bindable() has checked that E is normalisable.
[] =:= ordsets:to_list(ordsets:subtract(qlc:vars(Value), Imported)).
is_bindable(Value) ->
case normalise(Value) of
{ok, _C} ->
true;
not_ok ->
false
end.
pattern(P0, AnonI, Frame0, BindFun, State) ->
P1 = try
expand_pattern_records(P0, State)
catch _:_ -> P0 % template, records already expanded
end,
%% Makes test for equality simple:
P2 = reset_anno(P1),
{P3, AnonN} = anon_var(P2, AnonI),
{P4, F1} = match_in_pattern(tuple2cons(P3), Frame0, BindFun),
{P, F2} = element_calls(P4, F1, BindFun, _Imp=[]), % kludge for templates
{var, _, PatternVar} = UniqueVar = unique_var(),
F = unify('=:=', UniqueVar, P, F2, BindFun, _Imported = []),
{F, AnonN, PatternVar}.
frame2frames(failed) ->
[];
frame2frames(F) ->
[F].
match_in_pattern({match, _, E10, E20}, F0, BF) ->
{E1, F1} = match_in_pattern(E10, F0, BF),
{E2, F} = match_in_pattern(E20, F1, BF),
%% This is for join: chosing a constant could "hide" a variable.
E = case BF('=:=', E1) of
true -> E1;
false -> E2
end,
{E, unify('=:=', E1, E2, F, BF, _Imported = [])};
match_in_pattern(T, F0, BF) when is_tuple(T) ->
{L, F} = match_in_pattern(tuple_to_list(T), F0, BF),
{list_to_tuple(L), F};
match_in_pattern([E0 | Es0], F0, BF) ->
{E, F1} = match_in_pattern(E0, F0, BF),
{Es, F} = match_in_pattern(Es0, F1, BF),
{[E | Es], F};
match_in_pattern(E, F, _BF) ->
{E, F}.
-define(ANON_VAR(N), N).
anon_var(E, AnonI) ->
var_mapfold(fun({var, L, '_'}, N) ->
{{var, L, ?ANON_VAR(N)}, N+1};
(Var, N) -> {Var, N}
end, AnonI, E).
reset_anno(T) ->
set_anno(T, anno0()).
set_anno(T, A) ->
map_anno(fun(_L) -> A end, T).
-record(fstate, {state, bind_fun, imported}).
filter(_E, []=Frames0, _BF, _State, _Imported) ->
Frames0;
filter(E0, Frames0, BF, State, Imported) ->
E = pre_expand(E0),
FState = #fstate{state = State, bind_fun = BF, imported = Imported},
filter1(E, Frames0, FState).
%% One frame for each path through the and/or expression.
%%
%% "A xor B" is equal to "(A and not B) or (not A and B)".
%% Ignoring "not B" and "not A" this is the same as "A or B";
%% "xor" can be handled just as "or".
%%
%% One must handle filters with care, both when joining and when
%% looking up values. The reference is a nested loop: if the filter
%% fails for some combination of values, it must fail also when
%% looking up values or joining. In other words, the excluded
%% combinations of values must not evaluate to anything but 'false'.
%% Filters looking like guards are allowed to fail since for such
%% filter the so called guard semantics ensures that the value is
%% 'false' if it is not 'true'. This behavior was inherited from the
%% ordinary list comprehension, where it has been considered a bug
%% kept for backward compatibility. Now it has become part of the QLC
%% semantics, and hard to change (at least in the qlc module).
%%
%% A special case is =/2. If there is a chance that the =/2 fails
%% (badmatch) for some combination of values, that combination cannot
%% be excluded. If the variable is bound only once, it is OK, but not
%% twice (or more). The current implementation does not handle =/2 at
%% all (except in generator patterns).
filter1({op, _, Op, L0, R0}, Fs, FS) when Op =:= '=:='; Op =:= '==' ->
#fstate{state = S, bind_fun = BF, imported = Imported} = FS,
%% In the transformed code there are no records in lookup values
%% because records are expanded away in prep_expr.
lists:flatmap(fun(F0) ->
{L, F1} = prep_expr(L0, F0, S, BF, Imported),
{R, F2} = prep_expr(R0, F1, S, BF, Imported),
case unify(Op, L, R, F2, BF, Imported) of
failed -> [];
F -> [F]
end
end, Fs);
filter1({op, _, Op, L, R}, Fs, FS) when Op =:= 'and'; Op =:= 'andalso' ->
filter1(R, filter1(L, Fs, FS), FS);
filter1({op, _, Op, L, R}, Fs, FS) when Op =:= 'or';
Op =:= 'orelse';
Op =:= 'xor' ->
filter1(L, Fs, FS) ++ filter1(R, Fs, FS);
filter1({atom,_,Atom}, _Fs, _FS) when Atom =/= true ->
[];
filter1({call,L,{remote,_,{atom,_,erlang},{atom,_,is_record}},[T,R]},
Fs, FS) ->
filter1({op,L,'=:=',{call,L,{remote,L,{atom,L,erlang},{atom,L,element}},
[{integer,L,1},T]},R},
Fs, FS);
%% erlang:is_record/3 (the size information is ignored):
filter1({call,L,{remote,L1,{atom,_,erlang}=M,{atom,L2,is_record}},[T,R,_Sz]},
Fs, FS) ->
filter1({call,L,{remote,L1,M,{atom,L2,is_record}},[T,R]}, Fs, FS);
filter1(_E, Fs, _FS) ->
Fs.
%% filter() tries to extract as much information about constant
%% columns as possible. It ignores those parts of the filter that are
%% uninteresting. safe_filter() on the other hand ensures that the
%% bindings returned capture _all_ aspects of the filter (wrt BF).
safe_filter(_E, []=Frames0, _BF, _State, _Imported) ->
Frames0;
safe_filter(E0, Frames0, BF, State, Imported) ->
E = pre_expand(E0),
FState = #fstate{state = State, bind_fun = BF, imported = Imported},
safe_filter1(E, Frames0, FState).
safe_filter1({op, _, Op, L0, R0}, Fs, FS) when Op =:= '=:='; Op =:= '==' ->
#fstate{state = S, bind_fun = BF, imported = Imported} = FS,
lists:flatmap(fun(F0) ->
{L, F1} = prep_expr(L0, F0, S, BF, Imported),
{R, F2} = prep_expr(R0, F1, S, BF, Imported),
case safe_unify(Op, L, R, F2, BF, Imported) of
failed -> [];
F -> [F]
end
end, Fs);
safe_filter1({op, _, Op, L, R}, Fs, FS) when Op =:= 'and'; Op =:= 'andalso' ->
safe_filter1(R, safe_filter1(L, Fs, FS), FS);
safe_filter1({op, _, Op, L, R}, Fs, FS) when Op =:= 'or'; Op =:= 'orelse' ->
safe_filter1(L, Fs, FS) ++ safe_filter1(R, Fs, FS);
safe_filter1({atom,_,true}, Fs, _FS) ->
Fs;
safe_filter1(_E, _Fs, _FS) ->
[].
%% Substitutions:
%% M:F() for {M,F}(); erlang:F() for F(); is_record() for record().
pre_expand({call,L1,{atom,L2,record},As}) ->
pre_expand({call,L1,{atom,L2,is_record},As});
pre_expand({call,L,{atom,_,_}=F,As}) ->
pre_expand({call,L,{remote,L,{atom,L,erlang},F},As});
pre_expand({call,L,{tuple,_,[M,F]},As}) ->
pre_expand({call,L,{remote,L,M,F},As});
pre_expand(T) when is_tuple(T) ->
list_to_tuple(pre_expand(tuple_to_list(T)));
pre_expand([E | Es]) ->
[pre_expand(E) | pre_expand(Es)];
pre_expand(T) ->
T.
%% -> [ [{{QualifierNumber,ColumnNumber}, [Value]}] ]
frames_to_columns([], _PatternVars, _DerefFun, _SelectorFun, _Imp, _CompOp) ->
[];
frames_to_columns(Fs, PatternVars, DerefFun, SelectorFun, Imp, CompOp) ->
%% It is important that *the same* variables are introduced for
%% columns in every frame. (When trying to find constant columns
%% it doesn't matter, but when trying to find joined columns, the
%% same variables have to be the representatives in every frame.)
SizesVarsL =
[begin
PatVar = {var,anno0(),PV},
PatternSizes = [pattern_size([F], PatVar, false) ||
F <- Fs],
MaxPZ = lists:max([0 | PatternSizes -- [undefined]]),
Vars = pat_vars(MaxPZ),
{PatternId#qid.no, PatVar, PatternSizes, Vars}
end || {PatternId, PV} <- PatternVars],
BF = fun(_Op, Value) -> is_bindable(Value) end,
Fun = fun({_PatN, PatVar, PatSizes, Vars}, Frames) ->
[unify('=:=', pat_tuple(Sz, Vars), PatVar, Frame, BF, Imp) ||
{Sz, Frame} <- lists:zip(PatSizes, Frames)]
end,
NFs = lists:foldl(Fun, Fs, SizesVarsL),
[frames2cols(NFs, PatN, PatSizes, Vars, DerefFun, SelectorFun, CompOp) ||
{PatN, _PatVar, PatSizes, Vars} <- SizesVarsL].
frames2cols(Fs, PatN, PatSizes, Vars, DerefFun, SelectorFun, CompOp) ->
Rs = [ begin
RL = [{{PatN,Col},cons2tuple(element(2, Const))} ||
{V, Col} <- lists:zip(lists:sublist(Vars, PatSz),
lists:seq(1, PatSz)),
%% Do not handle the case where several
%% values compare equal, e.g. "X =:= 1
%% andalso X == 1.0". Looking up both
%% values or one of them won't always do
%% because it is more or less undefined
%% whether the table returns the given key
%% or the one stored in the table. Or
%% rather, it would be strange if the table
%% did not return the stored key upon
%% request, but the 'lookup_fun' function
%% may have to add the given key (see also
%% gb_table in qlc(3)). (Not a very strong
%% argument. "X =:= 1" could (should?) be
%% seen as a bug.) Note: matching tables
%% cannot skip the filter, but looking up
%% one of the values should be OK.
tl(Consts = DerefFun(V, F)) =:= [],
(Const = (SelectorFun(F))(hd(Consts))) =/= no],
sofs:relation(RL) % possibly empty
end || {F,PatSz} <- lists:zip(Fs, PatSizes)],
Ss = sofs:from_sets(Rs),
%% D: columns occurring in every frame (path).
D = sofs:intersection(sofs:projection(fun(S) -> sofs:projection(1, S) end,
Ss)),
Cs = sofs:restriction(sofs:relation_to_family(sofs:union(Ss)), D),
[C || {_,Vs}=C <- sofs:to_external(Cs), not col_ignore(Vs, CompOp)].
pat_vars(N) ->
[unique_var() || _ <- lists:seq(1, N)].
pat_tuple(Sz, Vars) when is_integer(Sz), Sz > 0 ->
TupleTail = unique_var(),
{cons_tuple, list2cons(lists:sublist(Vars, Sz) ++ TupleTail)};
pat_tuple(_, _Vars) ->
unique_var().
%% Do not handle tests as "X =:= 1.0 orelse X == 1" either.
%% Similar problems as described above.
col_ignore(_Vs, '=:=') ->
false;
col_ignore(Vs, '==') ->
length(Vs) =/= length(lists:usort([element(2, normalise(V)) || V <- Vs])).
pattern_sizes(PatternVars, Fs) ->
[{QId#qid.no, Size} ||
{QId,PV} <- PatternVars,
undefined =/= (Size = pattern_size(Fs, {var,anno0(),PV}, true))].
pattern_size(Fs, PatternVar, Exact) ->
Fun = fun(F) -> (deref_pattern(_Imported = []))(PatternVar, F) end,
Derefs = lists:flatmap(Fun, Fs),
Szs = [pattern_sz(Cs, 0, Exact) || {cons_tuple, Cs} <- Derefs],
case lists:usort(Szs) of
[Sz] when is_integer(Sz), Sz >= 0 -> Sz;
[] when not Exact -> 0;
_ -> undefined
end.
pattern_sz({cons,_,_C,E}, Col, Exact) ->
pattern_sz(E, Col+1, Exact);
pattern_sz({nil,_}, Sz, _Exact) ->
Sz;
pattern_sz(_, _Sz, true) ->
undefined;
pattern_sz(_, Sz, false) ->
Sz.
deref_pattern(Imported) ->
fun(PV, F) -> deref_values(PV, F, Imported) end.
prep_expr(E, F, S, BF, Imported) ->
element_calls(tuple2cons(expand_expr_records(E, S)), F, BF, Imported).
unify_column(Frame, Var, Col, BindFun, Imported) ->
A = anno0(),
Call = {call,A,{remote,A,{atom,A,erlang},{atom,A,element}},
[{integer,A,Col}, {var,A,Var}]},
element_calls(Call, Frame, BindFun, Imported).
%% cons_tuple is used for representing {V1, ..., Vi | TupleTail}.
%%
%% Tests like "element(2, X) =:= a" are represented by "tuple tails":
%% {_, a | _}. The tail may be unified later, when more information
%% about the size of the tuple is known.
element_calls({call,_,{remote,_,{atom,_,erlang},{atom,_,element}},
[{integer,_,I},Term0]}, F0, BF, Imported) when I > 0 ->
%% Note: erl_expand_records ensures that all calls to element/2
%% have an explicit "erlang:" prefix.
TupleTail = unique_var(),
VarsL = [unique_var() || _ <- lists:seq(1, I)],
Vars = VarsL ++ TupleTail,
Tuple = {cons_tuple, list2cons(Vars)},
VarI = lists:nth(I, VarsL),
{Term, F} = element_calls(Term0, F0, BF, Imported),
{VarI, unify('=:=', Tuple, Term, F, BF, Imported)};
element_calls(T, F0, BF, Imported) when is_tuple(T) ->
{L, F} = element_calls(tuple_to_list(T), F0, BF, Imported),
{list_to_tuple(L), F};
element_calls([E0 | Es0], F0, BF, Imported) ->
{E, F1} = element_calls(E0, F0, BF, Imported),
{Es, F} = element_calls(Es0, F1, BF, Imported),
{[E | Es], F};
element_calls(E, F, _BF, _Imported) ->
{E, F}.
unique_var() ->
{var, anno0(), make_ref()}.
is_unique_var({var, _L, V}) ->
is_reference(V).
expand_pattern_records(P, State) ->
A = anno0(),
E = {'case',A,{atom,A,true},[{clause,A,[P],[],[{atom,A,true}]}]},
{'case',_,_,[{clause,A,[NP],_,_}]} = expand_expr_records(E, State),
NP.
expand_expr_records(E, State) ->
RecordDefs = State#state.records,
A = anno1(),
Forms0 = RecordDefs ++ [{function,A,foo,0,[{clause,A,[],[],[pe(E)]}]}],
Forms = erl_expand_records:module(Forms0, [no_strict_record_tests]),
{function,_,foo,0,[{clause,_,[],[],[NE]}]} = lists:last(Forms),
NE.
%% Partial evaluation.
pe({op,Line,Op,A}) ->
erl_eval:partial_eval({op,Line,Op,pe(A)});
pe({op,Line,Op,L,R}) ->
erl_eval:partial_eval({op,Line,Op,pe(L),pe(R)});
pe(T) when is_tuple(T) ->
list_to_tuple(pe(tuple_to_list(T)));
pe([E | Es]) ->
[pe(E) | pe(Es)];
pe(E) ->
E.
unify(Op, E1, E2, F, BF, Imported) ->
unify(Op, E1, E2, F, BF, Imported, false).
safe_unify(Op, E1, E2, F, BF, Imported) ->
unify(Op, E1, E2, F, BF, Imported, true).
unify(_Op, _E1, _E2, failed, _BF, _Imported, _Safe) -> % contradiction
failed;
unify(_Op, E, E, F, _BF, _Imported, _Safe) ->
F;
unify(Op, {var, _, _}=Var, E2, F, BF, Imported, Safe) ->
extend_frame(Op, Var, E2, F, BF, Imported, Safe);
unify(Op, E1, {var, _, _}=Var, F, BF, Imported, Safe) ->
extend_frame(Op, Var, E1, F, BF, Imported, Safe);
unify(Op, {cons_tuple, Es1}, {cons_tuple, Es2}, F, BF, Imported, Safe) ->
unify(Op, Es1, Es2, F, BF, Imported, Safe);
unify(Op, {cons, _, L1, R1}, {cons, _, L2, R2}, F, BF, Imported, Safe) ->
E = unify(Op, L1, L2, F, BF, Imported, Safe),
unify(Op, R1, R2, E, BF, Imported, Safe);
unify(Op, E1, E2, F, _BF, _Imported, Safe) ->
try
{ok, C1} = normalise(E1),
{ok, C2} = normalise(E2),
if
Op =:= '=:=', C1 =:= C2 ->
F;
Op =:= '==', C1 == C2 ->
F;
true ->
failed
end
catch error:_ when Safe -> failed;
error:_ when not Safe -> F % ignored
end.
%% Binaries are not handled at all (by unify).
%% Note that a variable can be bound to several values, for instance:
%% X =:= 3, X == 3.0. As a consequence, deref() returns a list of
%% values.
%% Binding a variable to several values makes the unification and
%% dereferencing more complicated. An alternative would be not to try
%% to find lookup values for such QLCs at all. That might have been a
%% better design decision.
-record(bind, {var, value, op}).
extend_frame(Op, Var, Value, F, BF, Imported, Safe) ->
case var_values(Var, F) of
[] ->
case Value of
{var, _, _} ->
case var_values(Value, F) of
[] ->
add_binding(Op, Value, Var, F, BF, Imported, Safe);
ValsOps ->
maybe_add_binding(ValsOps, Op, Value, Var, F,
BF, Imported, Safe)
end;
_ ->
add_binding(Op, Var, Value, F, BF, Imported, Safe)
end;
ValsOps ->
maybe_add_binding(ValsOps, Op, Var, Value, F, BF, Imported, Safe)
end.
maybe_add_binding(ValsOps, Op, Var, Value, F0, BF, Imported, Safe) ->
case unify_var_bindings(ValsOps, Op, Value, F0, BF, Imported, Safe) of
failed ->
failed;
F ->
case already_bound(Op, Var, Value, F) of
true ->
F;
false ->
add_binding(Op, Var, Value, F, BF, Imported, Safe)
end
end.
already_bound(Op, Var, Value, F) ->
%% Note: all variables are treated as imported. The dereferenced
%% values must not depend on Imported.
BFun = fun(_DV, BOp) -> Op =:= BOp end,
DerefValue = deref_value(Value, Op, F, BFun, all),
DerefVar = deref_var(Var, F, BFun, all),
DerefValue -- DerefVar =:= [].
unify_var_bindings([], _Op, _Value, F, _BF, _Imported, _Safe) ->
F;
unify_var_bindings([{VarValue, Op2} | Bindings],
Op1, Value, F0, BF, Imported, Safe) ->
Op = deref_op(Op1, Op2),
case unify(Op, VarValue, Value, F0, BF, Imported, Safe) of
failed ->
failed;
F ->
unify_var_bindings(Bindings, Op1, Value, F, BF, Imported, Safe)
end.
deref_op('=:=', '=:=') ->
'=:=';
deref_op(_, _) ->
'=='.
%%% Note: usort works; {integer,L,3} does not match {float,L,3.0}.
var_values(Var, Frame) ->
[{Value, Op} ||
#bind{value = Value, op = Op} <- var_bindings(Var, Frame)].
deref_var(Var, Frame, Imported) ->
deref_var(Var, Frame, fun(_DV, _Op) -> true end, Imported).
deref_var(Var, Frame, BFun, Imported) ->
lists:usort([ValOp ||
#bind{value = Value, op = Op} <- var_bindings(Var, Frame),
ValOp <- deref_value(Value, Op, Frame, BFun, Imported)]).
deref_value(Value, Op, Frame, BFun, Imported) ->
lists:usort([{Val,value_op(ValOp, Op, Imported)} ||
{Val,_Op}=ValOp <- deref(Value, Frame, BFun, Imported)]).
add_binding(Op, Var0, Value0, F, BF, Imported, Safe) ->
{Var, Value} = maybe_swap_var_value(Var0, Value0, F, Imported),
case BF(Op, Value) of
true ->
add_binding2(Var, Value, Op, F);
false when Safe ->
failed;
false when not Safe ->
F
end.
add_binding2(Var, Value, Op, F) ->
case occurs(Var, Value, F) of
true ->
failed;
false ->
[#bind{var = Var, value = Value, op = Op} | F]
end.
%% Ensure that imported variables are visible in the dereferenced
%% value by pushing them to the end of the binding chain. Be careful
%% not to introduce loops.
maybe_swap_var_value(Var, Value, Frame, Imported) ->
case do_swap_var_value(Var, Value, Frame, Imported) of
true ->
{Value, Var};
false ->
{Var, Value}
end.
do_swap_var_value({var, _, V1}=Var1, {var, _, V2}=Var2, F, Imported) ->
case swap_vv(Var1, Var2, F) of
[] ->
case swap_vv(Var2, Var1, F) of
[] ->
ordsets:is_element(V1, Imported) andalso
not ordsets:is_element(V2, Imported);
_Bs ->
true
end;
_Bs ->
false
end;
do_swap_var_value(_, _, _F, _Imp) ->
false.
swap_vv(V1, V2, F) ->
[V || #bind{value = V} <- var_bindings(V1, F), V =:= V2].
normalise(E) ->
%% Tuple tails are OK.
case catch erl_parse:normalise(var2const(cons2tuple(E))) of
{'EXIT', _} ->
not_ok;
C ->
{ok, C}
end.
occurs(V, V, _F) ->
true;
occurs(V, {var, _, _} = Var, F) ->
lists:any(fun(B) -> occurs(V, B#bind.value, F) end, var_bindings(Var, F));
occurs(V, T, F) when is_tuple(T) ->
lists:any(fun(E) -> occurs(V, E, F) end, tuple_to_list(T));
occurs(V, [E | Es], F) ->
occurs(V, E, F) orelse occurs(V, Es, F);
occurs(_V, _E, _F) ->
false.
deref_values(E, Frame, Imported) ->
deref_values(E, Frame, fun(_DV, _Op) -> true end, Imported).
deref_values(E, Frame, BFun, Imported) ->
lists:usort([V ||
{V, Op} <- deref(E, Frame, BFun, Imported),
BFun(V, Op)]).
deref(E, F, Imp) ->
BFun = fun(_DV, _Op) -> true end,
deref(E, F, BFun, Imp).
deref({var, _, _}=V, F, BFun, Imp) ->
DBs = lists:flatmap(fun(B) -> deref_binding(B, F, BFun, Imp)
end, var_bindings(V, F)),
case DBs of
[] ->
[{V, '=:='}];
_ ->
lists:usort(DBs)
end;
deref(T, F, BFun, Imp) when is_tuple(T) ->
[{list_to_tuple(DL), Op} ||
{DL, Op} <- deref(tuple_to_list(T), F, BFun, Imp)];
deref(Es, F, BFun, Imp) when is_list(Es) ->
L = [deref(C, F, BFun, Imp) || C <- Es],
lists:usort([deref_list(S) || S <- all_comb(L)]);
deref(E, _F, _BFun, _Imp) ->
[{E, '=:='}].
var_bindings(Var, F) ->
[B || #bind{var = V}=B <- F, V =:= Var].
deref_binding(Bind, Frame, BFun, Imp) ->
#bind{value = Value, op = Op0} = Bind,
[{Val, Op} ||
{Val, _Op}=ValOp <- deref(Value, Frame, BFun, Imp),
BFun(Val, Op = value_op(ValOp, Op0, Imp))].
deref_list(L) ->
Op = case lists:usort([Op || {_Val, Op} <- L]) of
['=:='] ->
'=:=';
_ ->
'=='
end,
{[V || {V, _Op} <- L], Op}.
value_op({_V, '=='}, _BindOp, _Imp) ->
'==';
value_op({_V, '=:='}, _BindOp='=:=', _Imp) ->
'=:=';
value_op({V, '=:='}, _BindOp='==', Imp) ->
case free_of_integers(V, Imp) of
true ->
'=:=';
false ->
'=='
end.
all_comb([]) ->
[[]];
all_comb([Cs | ICs]) ->
[[C | L] || C <- Cs, L <- all_comb(ICs)].
%% "Free of integers" here means that there are not imported variables
%% in V (which could take on integer values), but there may be other
%% variables in V.
free_of_integers(V, Imported) ->
not has_integer(V) andalso not has_imported_vars(V, Imported).
%% Assumes that imported variables are representatives, if Value is a
%% dereferenced value.
has_imported_vars(Value, all) ->
qlc:vars(Value) =/= [];
has_imported_vars(Value, Imported) ->
[Var || Var <- qlc:vars(Value), lists:member(Var, Imported)] =/= [].
has_integer(Abstr) ->
try
has_int(Abstr)
catch throw:true -> true
end.
has_int({integer,_,I}) when float(I) == I ->
throw(true);
has_int({float,_,F}) when round(F) == F ->
throw(true);
has_int(T) when is_tuple(T) ->
has_int(tuple_to_list(T));
has_int([E | Es]) ->
has_int(E),
has_int(Es);
has_int(_) ->
false.
tuple2cons({tuple, _, Es}) ->
{cons_tuple, list2cons(tuple2cons(Es))};
tuple2cons(T) when is_tuple(T) ->
list_to_tuple(tuple2cons(tuple_to_list(T)));
tuple2cons([E | Es]) ->
[tuple2cons(E) | tuple2cons(Es)];
tuple2cons(E) ->
E.
list2cons([E | Es]) ->
{cons, anno0(), E, list2cons(Es)};
list2cons([]) ->
{nil, anno0()};
list2cons(E) ->
E.
%% Returns {..., Variable} if Variable is a tuple tail.
cons2tuple({cons_tuple, Es}) ->
{tuple, anno0(), cons2list(Es)};
cons2tuple(T) when is_tuple(T) ->
list_to_tuple(cons2tuple(tuple_to_list(T)));
cons2tuple([E | Es]) ->
[cons2tuple(E) | cons2tuple(Es)];
cons2tuple(E) ->
E.
cons2list({cons, _, L, R}) ->
[cons2tuple(L) | cons2list(R)];
cons2list({nil, _}) ->
[];
cons2list(E) -> % tuple tail (always a variable)
[cons2tuple(E)].
%% Returns true if all bindings in F1 also occur in F2.
%% Viewing F1 and F2 as sets, the fact that F1 is a subset of F2 iff
%% F1 union F2 is equal to F2 is used. (This should take care of
%% issues with anonymous variables.)
bindings_is_subset(F1, F2, Imported) ->
BF = fun(_Op, _Value) -> true end, % don't need any test here
%% Extend F2 with the bindings in F1:
F = lists:foldl(fun(#bind{var = V, value = Value, op = Op}, Frame) ->
unify(Op, V, Value, Frame, BF, Imported)
end, F2, F1),
bindings_subset(F, F2, Imported) andalso bindings_subset(F2, F, Imported).
bindings_subset(F1, F2, Imp) ->
Vars = lists:usort([V || #bind{var = V} <- F1, not is_unique_var(V)]),
lists:all(fun(V) ->
deref_var(V, F1, Imp) =:= deref_var(V, F2, Imp)
end, Vars).
%% Recognizes all QLCs on the form [T || P <- LE, F] such that
%% ets:fun2ms(fun(P) when F -> T end) is a match spec. This is OK with
%% the guard semantics implemented in filter/_ below. If one chooses
%% not to have guard semantics, affected filters will have to be
%% recognized and excluded here as well.
try_ms(E, P, Fltr, State) ->
L = anno1(),
Fun = {'fun',L,{clauses,[{clause,L,[P],[[Fltr]],[E]}]}},
Expr = {call,L,{remote,L,{atom,L,ets},{atom,L,fun2ms}},[Fun]},
Form = {function,L,foo,0,[{clause,L,[],[],[Expr]}]},
X = ms_transform:parse_transform(State#state.records ++ [Form], []),
case catch
begin
{function,L,foo,0,[{clause,L,[],[],[MS0]}]} = lists:last(X),
MS = erl_parse:normalise(var2const(MS0)),
XMS = ets:match_spec_compile(MS),
true = ets:is_compiled_ms(XMS),
{ok, MS, MS0}
end of
{'EXIT', _Reason} ->
no;
Reply ->
Reply
end.
filters_as_one([]) ->
{atom, anno0(), true};
filters_as_one(FilterData) ->
[{_,{fil,Filter1}} | Filters] = lists:reverse(FilterData),
lists:foldr(fun({_QId,{fil,Filter}}, AbstF) ->
{op,anno0(),'andalso',Filter,AbstF}
end, Filter1, Filters).
qual_data(Qualifiers) ->
F = fun(T) ->
[{QId,Q} || {QId,_,_,Q} <- Qualifiers, element(1,Q) =:= T]
end,
{F(fil), F(gen)}.
set_field(Pos, Fs, Data) ->
lists:sublist(Fs, Pos-1) ++ [Data] ++ lists:nthtail(Pos, Fs).
qdata([{#qid{no = QIdNo},{_QIVs,{{gen,_P,LE,_GV},GoI,SI}}} | QCs], L) ->
Init = case LE of
{join, Op, Q1, Q2, H1, H2, Cs1_0, Cs2_0} ->
Cs1 = qcon(Cs1_0),
Cs2 = qcon(Cs2_0),
%% -- R12B-3: {nil,L}
%% R12B-4 --: {atom,L,v1}
Compat = {atom,L,v1}, % meant for redundant match spec
CF = closure({tuple,L,[Cs1,Cs2,Compat]}, L),
{tuple,L,[?A(join),?A(Op),?I(Q1),?I(Q2),H1,H2,CF]};
_ ->
closure(LE, L)
end,
%% Create qual_data (see qlc.erl):
{cons,L,{tuple,L,[?I(QIdNo),?I(GoI),?I(SI),{tuple,L,[?A(gen),Init]}]},
qdata(QCs, L)};
qdata([{#qid{no = QIdNo},{_QIVs,{{fil,_F},GoI,SI}}} | QCs], L) ->
%% Create qual_data (see qlc.erl):
{cons,L,{tuple,L,[?I(QIdNo),?I(GoI),?I(SI),?A(fil)]},qdata(QCs, L)};
qdata([], L) ->
{nil,L}.
qcon(Cs) ->
A = anno0(),
list2cons([{tuple,A,[{integer,A,Col},list2cons(qcon1(ConstOps))]} ||
{Col,ConstOps} <- Cs]).
qcon1(ConstOps) ->
A = anno0(),
[{tuple,A,[Const,abstr(Op, A)]} || {Const,Op} <- ConstOps].
%% The original code (in Source) is used for filters and the template
%% since the translated code can have QLCs and we don't want them to
%% be visible.
qcode(E, QCs, Source, L, State) ->
CL = [begin
Bin = term_to_binary(C, [compressed]),
{bin, L, [{bin_element, L,
{string, L, binary_to_list(Bin)},
default, default}]}
end || {_,C} <- lists:keysort(1, [{qlc:template_state(),E} |
qcode(QCs, Source, State)])],
{'fun', L, {clauses, [{clause, L, [], [], [{tuple, L, CL}]}]}}.
qcode([{_QId, {_QIvs, {{gen,P,_LE,_GV}, GoI, _SI}}} | QCs], Source, State) ->
[{GoI,undo_no_shadows(P, State)} | qcode(QCs, Source, State)];
qcode([{QId, {_QIVs, {{fil,_F}, GoI, _SI}}} | QCs], Source, State) ->
{ok,OrigF} = dict:find(QId, Source),
[{GoI,undo_no_shadows(OrigF, State)} | qcode(QCs, Source, State)];
qcode([], _Source, _State) ->
[].
closure(Code, L) ->
{'fun',L,{clauses,[{clause,L,[],[],[Code]}]}}.
simple(L, Var, Init, Anno) ->
{tuple,L,[?A(simple_v1),?A(Var),Init,abstr(loc(Anno), Anno)]}.
clauses([{QId,{QIVs,{QualData,GoI,S}}} | QCs], RL, Fun, Go, NGV, E, IVs,St) ->
?DEBUG("QIVs = ~p~n", [QIVs]),
?DEBUG("IVs = ~p~n", [IVs]),
?DEBUG("GoI = ~p, S = ~p~n", [GoI, S]),
L = no_compiler_warning(get_lcid_line(QId#qid.lcid)),
Cs = case QualData of
{gen,P,_LE,GV} ->
generator(S, QIVs, P, GV, NGV, E, IVs, RL, Fun, Go,GoI,L,St);
{fil,F} ->
filter(F, L, QIVs, S, RL, Fun, Go, GoI, IVs, St)
end,
Cs ++ clauses(QCs, RL, Fun, Go, NGV, E, IVs, St);
clauses([], _RL, _Fun, _Go, _NGV, _IVs, _E, _St) ->
[].
final(RL, IVs, L, State) ->
IAs = replace(IVs, IVs, '_'),
AsL = pack_args([?I(0) | abst_vars([RL, '_', '_'] ++ IAs, L)], L, State),
Grd = [is_list_c(RL, L)],
Rev = {call,L,{remote,L,?A(lists),?A(reverse)},[?V(RL)]},
CL = {clause,L,AsL,[Grd],[Rev]},
AsF = pack_args([?I(0) | abst_vars(['_', '_', '_'] ++ IAs, L)], L, State),
CF = {clause,L,AsF,[],[?ABST_NO_MORE]},
[CL, CF].
template(E, RL, Fun, Go, AT, L, IVs, State) ->
I = qlc:template_state(), GoI = qlc:template_state(),
ARL = {cons,L,E,abst_vars(RL, L)},
Next = next(Go, GoI, L),
As0 = abst_vars([RL, Fun, Go] ++ IVs, L),
As = pack_args([?I(I) | As0], L, State),
NAs = pack_args([Next, ARL] ++ abst_vars([Fun, Go] ++ IVs, L), L, State),
Grd = [is_list_c(RL, L)],
CL = {clause,L,As,[Grd],[{call,L,?V(Fun),NAs}]},
%% Extra careful here or arguments will be lifted into a wide fun.
F = case split_args([Next | As0], L, State) of
{ArgsL, ArgsT} ->
Call = {call,L,?V(Fun),ArgsL++[{var,L,AT}]},
{block,L,
[{match,L,{var,L,AT},ArgsT},
{'fun',L,{clauses,[{clause,L,[],[],[Call]}]}}]};
FNAs ->
{'fun',L,{clauses,[{clause,L,[],[],[{call,L,?V(Fun),FNAs}]}]}}
end,
CF = {clause,L,As,[],[?ABST_MORE(E, F)]},
[CL,CF].
generator(S, QIVs, P, GV, NGV, E, IVs, RL, Fun, Go, GoI, L, State) ->
ComAs = abst_vars([RL, Fun, Go], L),
InitC = generator_init(S, L, GV, RL, Fun, Go, GoI, IVs, State),
As = [?I(S + 1)| ComAs ++ abst_vars(replace(QIVs -- [GV], IVs, '_'), L)],
MatchS = next(Go, GoI + 1, L),
AsM0 = [MatchS | ComAs ++ abst_vars(replace([GV], IVs, NGV), L)],
AsM = pack_args(AsM0, L, State),
ContS = ?I(S + 1),
QIVs__GV = QIVs -- [GV],
Tmp = replace([GV], replace(QIVs__GV, IVs, nil), NGV),
AsC = pack_args([ContS | ComAs ++ abst_vars(Tmp, L)], L, State),
DoneS = next(Go, GoI, L),
AsD0 = [DoneS | ComAs ++ abst_vars(replace(QIVs, IVs, nil), L)],
AsD = pack_args(AsD0, L, State),
CsL = generator_list(P, GV, NGV, As, AsM, AsC, AsD, Fun, L, State),
CsF = generator_cont(P, GV, NGV, E, As, AsM, AsC, AsD, Fun, L, State),
[InitC | CsL ++ CsF].
generator_init(S, L, GV, RL, Fun, Go, GoI, IVs, State) ->
As0 = abst_vars([RL, Fun, Go] ++ replace([GV], IVs, '_'), L),
As = pack_args([?I(S) | As0], L, State),
Next = next(Go, GoI + 2, L),
NAs = pack_args([?I(S + 1) | replace([?V('_')], As0, Next)], L, State),
{clause,L,As,[],[{call,L,?V(Fun),NAs}]}.
generator_list(P, GV, NGV, As, AsM, AsC, AsD, Fun, L, State) ->
As1 = pack_args(replace([?V(GV)], As, {cons,L,P,?V(NGV)}), L, State),
As2 = pack_args(replace([?V(GV)], As, {cons,L,?V('_'),?V(NGV)}), L,State),
As3 = pack_args(replace([?V(GV)], As, {nil,L}), L, State),
CM = {clause,L,As1,[],[{call,L,?V(Fun),AsM}]},
CC = {clause,L,As2,[],[{call,L,?V(Fun),AsC}]},
CD = {clause,L,As3,[],[{call,L,?V(Fun),AsD}]},
[CM, CC, CD].
%% The clause 'CE' was added in R11B. The version of the generated was
%% however not incremented.
generator_cont(P, GV, NGV, E, As0, AsM, AsC, AsD, Fun, L, State) ->
As = pack_args(As0, L, State),
CF1 = ?ABST_MORE(P, ?V(NGV)),
CF2 = ?ABST_MORE(?V('_'), ?V(NGV)),
CF3 = ?ABST_NO_MORE,
CF4 = ?V(E),
CM = {clause,L,[CF1],[],[{call,L,?V(Fun),AsM}]},
CC = {clause,L,[CF2],[],[{call,L,?V(Fun),AsC}]},
CD = {clause,L,[CF3],[],[{call,L,?V(Fun),AsD}]},
CE = {clause,L,[CF4],[],[CF4]},
Cls = [CM, CC, CD, CE],
B = {'case',L,{call,L,?V(GV),[]},Cls},
[{clause,L,As,[],[B]}].
filter(E, L, QIVs, S, RL, Fun, Go, GoI, IVs, State) ->
IAs = replace(QIVs, IVs, '_'),
As = pack_args([?I(S) | abst_vars([RL, Fun, Go] ++ IAs, L)], L, State),
NAs = abst_vars([RL, Fun, Go] ++ IVs, L),
TNext = next(Go, GoI + 1, L),
FNext = next(Go, GoI, L),
NAsT = pack_args([TNext | NAs], L, State),
NAsF = pack_args([FNext | NAs], L, State),
%% This is the "guard semantics" used in ordinary list
%% comprehension: if a filter looks like a guard test, it returns
%% 'false' rather than fails.
Body = case erl_lint:is_guard_test(E, State#state.records) of
true ->
CT = {clause,L,[],[[E]],[{call,L,?V(Fun),NAsT}]},
CF = {clause,L,[],[[?A(true)]],[{call,L,?V(Fun),NAsF}]},
[{'if',L,[CT,CF]}];
false ->
CT = {clause,L,[?A(true)],[],[{call,L,?V(Fun),NAsT}]},
CF = {clause,L,[?A(false)],[],[{call,L,?V(Fun),NAsF}]},
[{'case',L,E,[CT,CF]}]
end,
[{clause,L,As,[],Body}].
pack_args(Args, L, State) ->
case split_args(Args, L, State) of
{ArgsL, ArgsT} ->
ArgsL ++ [ArgsT];
_ ->
Args
end.
split_args(Args, L, State) when length(Args) > State#state.maxargs ->
{lists:sublist(Args, State#state.maxargs-1),
{tuple,L,lists:nthtail(State#state.maxargs-1, Args)}};
split_args(Args, _L, _State) ->
Args.
%% Replace every element in IEs that is a member of Es by R, keep all
%% other elements as they are.
replace(Es, IEs, R) ->
[case lists:member(E, Es) of
true -> R;
false -> E
end || E <- IEs].
is_list_c(V, L) ->
{call,L,?A(is_list),[?V(V)]}.
next(Go, GoI, L) ->
{call,L,?A(element),[?I(GoI),?V(Go)]}.
aux_vars(Vars, LcN, AllVars) ->
[aux_var(Name, LcN, 0, 1, AllVars) || Name <- Vars].
aux_var(Name, LcN, QN, N, AllVars) ->
qlc:aux_name(lists:concat([Name, LcN, '_', QN, '_']), N, AllVars).
no_compiler_warning(L) ->
Anno = erl_anno:new(L),
erl_anno:set_generated(true, Anno).
loc(A) ->
erl_anno:location(A).
list2op([E], _Op) ->
E;
list2op([E | Es], Op) ->
{op,anno0(),Op,E,list2op(Es, Op)}.
anno0() ->
erl_anno:new(0).
anno1() ->
erl_anno:new(1).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
qual_fold(Fun, GlobAcc0, Acc0, Forms, State) ->
F = fun(Id, {lc,L,E,Qs0}, GA0) ->
{Qs,GA,_NA} = qual_fold(Qs0, Fun, GA0, Acc0, Id, 1, []),
{{lc,L,E,Qs},GA};
(_Id, Expr, GA) ->
{Expr,GA}
end,
qlc_mapfold(F, GlobAcc0, Forms, State).
qual_fold([Q0 | Qs], F, GA0, A0, Id, No, NQs) ->
QId = qid(Id, No),
{Q,GA,A} = F(QId, Q0, GA0, A0),
qual_fold(Qs, F, GA, A, Id, No + 1, [Q | NQs]);
qual_fold([], _F, GA, A, _Id, _No, NQs) ->
{lists:reverse(NQs),GA,A}.
qlc_mapfold(Fun, Acc0, Forms0, State) ->
{Forms, A, _NNo} = qlcmf(Forms0, Fun, State#state.imp, Acc0, 1),
erase(?QLC_FILE),
{Forms, A}.
qlcmf([E0 | Es0], F, Imp, A0, No0) ->
{E, A1, No1} = qlcmf(E0, F, Imp, A0, No0),
{Es, A, No} = qlcmf(Es0, F, Imp, A1, No1),
{[E | Es], A, No};
qlcmf(?QLC_Q(L1, L2, L3, L4, LC0, Os0), F, Imp, A0, No0) when length(Os0) < 2 ->
{Os, A1, No1} = qlcmf(Os0, F, Imp, A0, No0),
{LC, A2, No} = qlcmf(LC0, F, Imp, A1, No1), % nested...
NL = make_lcid(L1, No),
{T, A} = F(NL, LC, A2),
{?QLC_Q(L1, L2, L3, L4, T, Os), A, No + 1};
qlcmf(?IMP_Q(L1, L2, LC0, Os0), F, Imp=true, A0, No0) when length(Os0) < 2 ->
{Os, A1, No1} = qlcmf(Os0, F, Imp, A0, No0),
{LC, A2, No} = qlcmf(LC0, F, Imp, A1, No1), % nested...
NL = make_lcid(L, No),
{T, A} = F(NL, LC, A2),
{?IMP_Q(L1, L2, T, Os), A, No + 1};
qlcmf({attribute,_L,file,{File,_Line}}=Attr, _F, _Imp, A, No) ->
put(?QLC_FILE, File),
{Attr, A, No};
qlcmf(T, F, Imp, A0, No0) when is_tuple(T) ->
{TL, A, No} = qlcmf(tuple_to_list(T), F, Imp, A0, No0),
{list_to_tuple(TL), A, No};
qlcmf(T, _F, _Imp, A, No) ->
{T, A, No}.
occ_vars(E) ->
qlc:var_fold(fun({var,_L,V}) -> V end, [], E).
%% Every Anno is replaced by a unique number. The number is used in a
%% table that holds data about the abstract node where Anno resides.
%% In particular, the original location is kept there, so that the
%% original abstract code can be re-created.
save_anno(Abstr, NodeInfo) ->
F = fun(Anno) ->
N = next_slot(NodeInfo),
Location = erl_anno:location(Anno),
Data = {N, #{location => Location}},
true = ets:insert(NodeInfo, Data),
erl_anno:new(N)
end,
map_anno(F, Abstr).
next_slot(T) ->
I = ets:update_counter(T, var_n, 1),
case ets:lookup(T, I) of
[] ->
I;
_ ->
next_slot(T)
end.
restore_anno(Abstr, NodeInfo) ->
F = fun(Anno) ->
Location = erl_anno:location(Anno),
case ets:lookup(NodeInfo, Location) of
[{Location, Data}] ->
OrigLocation = maps:get(location, Data),
erl_anno:set_location(OrigLocation, Anno);
[{Location}] -> % generated code
Anno;
[] ->
Anno
end
end,
map_anno(F, Abstr).
restore_loc(Location, #state{node_info = NodeInfo}) ->
case ets:lookup(NodeInfo, Location) of
[{Location, #{location := OrigLocation}}] ->
OrigLocation;
[{Location}] ->
Location;
[] ->
Location
end.
no_shadows(Forms0, State) ->
%% Variables that may shadow other variables are introduced in
%% LCs and Funs. Such variables (call them SV, Shadowing
%% Variables) are now renamed. Each (new) occurrence in a pattern
%% is assigned an index (integer), unique in the file.
%%
%% The state {LastIndex,ActiveVars,UsedVars,AllVars,Singletons,State}
%% holds the last index used for each SV (LastIndex), the SVs in
%% the current scope (ActiveVars), used SVs (UsedVars, the indexed
%% name is the key), all variables occurring in the file
%% (AllVars), and all singletons. If an SV is not used (that is,
%% is a member of Singletons), it is replaced by '_' (otherwise a
%% warning for unused variable would erroneously be emitted). If
%% the indexed name of an SV occurs in the file, next index is
%% tried (to avoid mixing up introduced names with existing ones).
%%
%% The original names of variables are kept in a table in State.
%% undo_no_shadows/2 re-creates the original code.
AllVars = sets:from_list(ordsets:to_list(qlc:vars(Forms0))),
?DEBUG("nos AllVars = ~p~n", [sets:to_list(AllVars)]),
VFun = fun(_Id, LC, Vs) -> nos(LC, Vs) end,
LI = ets:new(?APIMOD,[]),
UV = ets:new(?APIMOD,[]),
D0 = dict:new(),
S1 = {LI, D0, UV, AllVars, [], State},
_ = qlc_mapfold(VFun, S1, Forms0, State),
?DEBUG("UsedIntroVars = ~p~n", [ets:match_object(UV, '_')]),
Singletons = ets:select(UV, ets:fun2ms(fun({K,0}) -> K end)),
?DEBUG("Singletons: ~p~n", [Singletons]),
true = ets:delete_all_objects(LI),
true = ets:delete_all_objects(UV),
%% Do it again, this time we know which variables are singletons.
S2 = {LI, D0, UV, AllVars, Singletons, State},
{Forms,_} = qlc_mapfold(VFun, S2, Forms0, State),
true = ets:delete(LI),
true = ets:delete(UV),
Forms.
nos([E0 | Es0], S0) ->
{E, S1} = nos(E0, S0),
{Es, S} = nos(Es0, S1),
{[E | Es], S};
nos({'fun',L,{clauses,Cs}}, S) ->
NCs = [begin
{H, S1} = nos_pattern(H0, S),
{[G, B], _} = nos([G0, B0], S1),
{clause,Ln,H,G,B}
end || {clause,Ln,H0,G0,B0} <- Cs],
{{'fun',L,{clauses,NCs}}, S};
nos({named_fun,Loc,Name,Cs}, S) ->
{{var,NLoc,NName}, S1} = case Name of
'_' ->
S;
Name ->
nos_pattern({var,Loc,Name}, S)
end,
NCs = [begin
{H, S2} = nos_pattern(H0, S1),
{[G, B], _} = nos([G0, B0], S2),
{clause,CLoc,H,G,B}
end || {clause,CLoc,H0,G0,B0} <- Cs],
{{named_fun,NLoc,NName,NCs}, S};
nos({lc,L,E0,Qs0}, S) ->
%% QLCs as well as LCs. It is OK to modify LCs as long as they
%% occur within QLCs--the warning messages have already been found
%% by compile_errors.
F = fun({T,Ln,P0,LE0}, QS0) when T =:= b_generate; T =:= generate ->
{LE, _} = nos(LE0, QS0),
{P, QS} = nos_pattern(P0, QS0),
{{T,Ln,P,LE}, QS};
(Filter, QS) ->
nos(Filter, QS)
end,
{Qs, S1} = lists:mapfoldl(F, S, Qs0),
{E, _} = nos(E0, S1),
{{lc,L,E,Qs}, S};
nos({var,L,V}=Var, {_LI,Vs,UV,_A,_Sg,State}=S) when V =/= '_' ->
case used_var(V, Vs, UV) of
{true, VN} ->
nos_var(L, V, State),
{{var,L,VN}, S};
false ->
{Var, S}
end;
nos(T, S0) when is_tuple(T) ->
{TL, S} = nos(tuple_to_list(T), S0),
{list_to_tuple(TL), S};
nos(T, S) ->
{T, S}.
nos_pattern(P, S) ->
{T, NS, _} = nos_pattern(P, S, []),
{T, NS}.
nos_pattern([P0 | Ps0], S0, PVs0) ->
{P, S1, PVs1} = nos_pattern(P0, S0, PVs0),
{Ps, S, PVs} = nos_pattern(Ps0, S1, PVs1),
{[P | Ps], S, PVs};
nos_pattern({var,L,V}, {LI,Vs0,UV,A,Sg,State}, PVs0) when V =/= '_' ->
{Name, Vs, PVs} =
case lists:keyfind(V, 1, PVs0) of
{V, VN} ->
_ = used_var(V, Vs0, UV),
{VN, Vs0, PVs0};
false ->
{VN, Vs1} = next_var(V, Vs0, A, LI, UV),
N = case lists:member(VN, Sg) of
true -> '_';
false -> VN
end,
{N, Vs1, [{V,VN} | PVs0]}
end,
nos_var(L, V, State),
{{var,L,Name}, {LI,Vs,UV,A,Sg,State}, PVs};
nos_pattern(T, S0, PVs0) when is_tuple(T) ->
{TL, S, PVs} = nos_pattern(tuple_to_list(T), S0, PVs0),
{list_to_tuple(TL), S, PVs};
nos_pattern(T, S, PVs) ->
{T, S, PVs}.
nos_var(Anno, Name, State) ->
NodeInfo = State#state.node_info,
Location = erl_anno:location(Anno),
case ets:lookup(NodeInfo, Location) of
[{Location, #{name := _}}] ->
true;
[{Location, Data}] ->
true = ets:insert(NodeInfo, {Location, Data#{name => Name}});
[] -> % cannot happen
true
end.
used_var(V, Vs, UV) ->
case dict:find(V, Vs) of
{ok,Value} ->
VN = qlc:name_suffix(V, Value),
_ = ets:update_counter(UV, VN, 1),
{true, VN};
error -> false
end.
next_var(V, Vs, AllVars, LI, UV) ->
NValue = case ets:lookup(LI, V) of
[{V, Value}] -> Value + 1;
[] -> 1
end,
true = ets:insert(LI, {V, NValue}),
VN = qlc:name_suffix(V, NValue),
case sets:is_element(VN, AllVars) of
true -> next_var(V, Vs, AllVars, LI, UV);
false -> true = ets:insert(UV, {VN, 0}),
NVs = dict:store(V, NValue, Vs),
{VN, NVs}
end.
undo_no_shadows(E, State) ->
var_map(fun(Anno) -> undo_no_shadows1(Anno, State) end, E).
undo_no_shadows1({var, Anno, _}=Var, State) ->
Location = erl_anno:location(Anno),
NodeInfo = State#state.node_info,
case ets:lookup(NodeInfo, Location) of
[{Location, #{name := Name}}] ->
{var, Anno, Name};
_ ->
Var
end.
%% QLC identifier.
%% The first one encountered in the file has No=1.
make_lcid(Anno, No) when is_integer(No), No > 0 ->
{No, erl_anno:line(Anno)}.
get_lcid_no({No, _Line}) ->
No.
get_lcid_line({_No, Line}) ->
Line.
qid(LCId, No) ->
#qid{no = No, lcid = LCId}.
abst_vars([V | Vs], L) ->
[abst_vars(V, L) | abst_vars(Vs, L)];
abst_vars([], _L) ->
[];
abst_vars(nil, L) ->
{nil,L};
abst_vars(V, L) ->
{var,L,V}.
embed_vars(Vars, L) ->
embed_expr({tuple,L,Vars}, L).
%% -> [Expr || _ <- []] on abstract format.
embed_expr(Expr, L) ->
{lc,L,Expr,[{generate,L,{var,L,'_'},{nil,L}}]}.
%% Doesn't handle binaries very well, but don't bother for now.
var2const(E) ->
var_map(fun({var, L, V}) -> {atom, L, V} end, E).
var_map(F, {var, _, _}=V) ->
F(V);
var_map(F, {named_fun,NLoc,NName,Cs}) ->
{var,Loc,Name} = F({var,NLoc,NName}),
{named_fun,Loc,Name,var_map(F, Cs)};
var_map(F, T) when is_tuple(T) ->
list_to_tuple(var_map(F, tuple_to_list(T)));
var_map(F, [E | Es]) ->
[var_map(F, E) | var_map(F, Es)];
var_map(_F, E) ->
E.
var_mapfold(F, A, {var, _, _}=V) ->
F(V, A);
var_mapfold(F, A0, T) when is_tuple(T) ->
{L, A} = var_mapfold(F, A0, tuple_to_list(T)),
{list_to_tuple(L), A};
var_mapfold(F, A0, [E0 | Es0]) ->
{E, A1} = var_mapfold(F, A0, E0),
{Es, A} = var_mapfold(F, A1, Es0),
{[E | Es], A};
var_mapfold(_F, A, E) ->
{E, A}.
map_anno(F, AbstrList) when is_list(AbstrList) ->
[map_anno1(F, Abstr) || Abstr <- AbstrList];
map_anno(F, Abstr) ->
map_anno1(F, Abstr).
map_anno1(F, Abstr) ->
erl_parse:map_anno(F, Abstr).
family_list(L) ->
sofs:to_external(family(L)).
family(L) ->
sofs:relation_to_family(sofs:relation(L)).
-ifdef(debug).
display_forms(Forms) ->
io:format("Forms ***~n"),
lists:foreach(fun(Form) ->
io:format("~ts~n", [catch erl_pp:form(Form)])
end, Forms),
io:format("End Forms ***~n").
-else.
display_forms(_) ->
ok.
-endif.
