%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 2004-2014. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in %% compliance with the License. You should have received a copy of the %% Erlang Public License along with this software. If not, it can be %% retrieved online at http://www.erlang.org/. %% %% Software distributed under the License is distributed on an "AS IS" %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See %% the License for the specific language governing rights 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 = []}). %-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()], Forms2 :: [erl_parse:abstract_form()], Options :: [Option], Option :: type_checker | compile:option()). parse_transform(Forms, Options) -> ?DEBUG("qlc Parse Transform~n", []), State = #state{imp = is_qlc_q_imported(Forms), maxargs = ?COMPILE_MAX_NUM_OF_ARGS, records = record_attributes(Forms)}, case called_from_type_checker(Options) of true -> %% The returned value should conform to the types, but %% need not evaluate to anything meaningful. L = 0, {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 -> FormsNoShadows = no_shadows(Forms, State), case compile_messages(Forms, FormsNoShadows, Options, State) of {[],[],Warnings} -> {NewForms, State1} = transform(FormsNoShadows, State), ExtraWs = State1#state.xwarnings, {[],WForms} = no_duplicates(NewForms, [], Warnings, ExtraWs, Options), WForms ++ NewForms; {E0,Errors,Warnings} -> {EForms,WForms} = no_duplicates(Forms, E0++Errors, Warnings, [], Options), EForms ++ WForms ++ Forms end end. -spec(transform_from_evaluator(LC, Bs) -> Expr when LC :: erl_parse:abstract_expr(), Expr :: erl_parse:abstract_expr(), Bs :: erl_eval:binding_struct()). transform_from_evaluator(LC, Bindings) -> ?DEBUG("qlc Parse Transform (Evaluator Version)~n", []), transform_expression(LC, Bindings, false). -spec(transform_expression(LC, Bs) -> Expr when LC :: erl_parse:abstract_expr(), Expr :: erl_parse:abstract_expr(), Bs :: erl_eval:binding_struct()). 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 = 1, 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, [])]}]}, Forms = [{attribute,L,file,{"foo",L}}, {attribute,L,module,foo}, F], State = #state{imp = false, maxargs = ?EVAL_MAX_NUM_OF_ARGS, records = record_attributes(Forms)}, Options = [], FormsNoShadows = no_shadows(Forms, State), case compile_messages(Forms, FormsNoShadows, Options, State) of {[],[],_Warnings} -> {NewForms,_State1} = transform(FormsNoShadows, State), {function,L,bar,Ar,[{clause,L,As,[],[NF]}]} = lists:last(NewForms), {ok,NF}; {E0,Errors,_Warnings} when WithLintErrors -> {not_ok,mforms(error, E0 ++ Errors)}; {E0,Errors0,_Warnings} -> [{error,Reason} | _] = mforms(error, E0++Errors0), {not_ok, {error, ?APIMOD, Reason}} end. -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, ExtraWarnings, Options) -> %% Some mistakes such as "{X} =:= {}" are found by strong %% validation as well as by qlc. Prefer the warnings from qlc: 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 = 0, ML = lists:flatmap(fun({File,Ms}) -> [[{attribute,Line,file,{File,Line}}, {Tag,M}] || M <- Ms] end, lists:sort(L)), lists:flatten(lists:sort(ML)). 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, [], [], FormsNoShadows, State), GenForm = used_genvar_check(FormsNoShadows, State), ?DEBUG("GenForm = ~ts~n", [catch erl_pp:form(GenForm)]), WarnFun = fun(Id, LC, A) -> {tag_lines(LC, get_lcid_no(Id)), A} end, {WForms,ok} = qlc_mapfold(WarnFun, ok, Forms, State), {Es,Ws} = compile_forms(WForms ++ [GenForm], Options), {badarg(Forms, State),tagged_messages(Es)++BGens,tagged_messages(Ws)}. 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. tag_lines(E, No) -> map_lines(fun(Id) -> case is_lcid(Id) of true -> Id; false -> make_lcid(Id, No) end end, E). map_lines(F, E) -> erl_lint:modify_line(E, F). tagged_messages(MsL) -> [{File, [{Loc,Mod,untag(T)} || {Loc0,Mod,T} <- Ms, {true,Loc} <- [tloc(Loc0)]]} || {File,Ms} <- MsL] ++ [{File,[{Loc,?APIMOD,{used_generator_variable,V}}]} || {_, Ms} <- MsL, {XLoc,erl_lint,{unbound_var,_}} <- Ms, {Loc,File,V} <- [extra(XLoc)]]. tloc({Id,Column}) -> {IsLcid,T} = tloc(Id), {IsLcid,{T,Column}}; tloc(Id) -> IsLcid = is_lcid(Id), {IsLcid,case IsLcid of true -> get_lcid_line(Id); false -> any end}. extra({extra,Line,File,V}) -> {Line,File,V}; extra({Line,Column}) -> case extra(Line) of {L,File,V} -> {{L,Column},File,V}; Else -> Else end; extra(Else) -> Else. untag([E | Es]) -> [untag(E) | untag(Es)]; untag(T) when is_tuple(T) -> list_to_tuple(untag(tuple_to_list(T))); untag(E) -> case is_lcid(E) of true -> get_lcid_line(E); false -> E 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) -> 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)), Id = QId#qid.lcid, LC1 = embed_vars(intro_set_line({QId,f1}, Vs), Id), LC2 = embed_vars(intro_set_line({QId,f2}, Vs), Id), AnyLine = -1, 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} || {{QId,f1},erl_lint,{unbound_var,V}} <- Es0], After = [{QId,V} || {{QId,f2},erl_lint,{unbound_var,V}} <- Es0], Unsafe = [{QId,V} || {{QId,f2},erl_lint,{unsafe_var,V,_Where}} <- Es0], ?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_set_line(Tag, Vars) -> L = erl_parse:set_line(1, fun(_) -> Tag end), [{var,L,V} || V <- Vars]. 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. -define(MAX_NUM_OF_LINES, 23). % assume max 1^23 lines (> 8 millions) compile_forms(Forms0, Options) -> Forms = [F || F <- Forms0, element(1, F) =/= eof] ++ [{eof,1 bsl ?MAX_NUM_OF_LINES}], 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. %% The messages have the form %% {{extra,LineNo,File,Var},Module,{unbound_var,V}}, where Var is the %% original variable name and V is the name invented by no_shadows/2. %% used_genvar_check(FormsNoShadows, State) -> F = fun(QId, {T, Ln, _P, LE}=Q, {QsIVs0, Exprs0}, IVsSoFar0) when T =:= b_generate; T =:= generate -> F = fun({var, _, V}=Var) -> {var, L, OrigVar} = undo_no_shadows(Var), AF = fun(Line) -> {extra, Line, get(?QLC_FILE), OrigVar} end, L2 = erl_parse:set_line(L, AF), {var, L2, V} 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, IntroVars = intro_variables(FormsNoShadows, State), Acc0 = {IntroVars, [{atom, 0, true}]}, {_, {[], Exprs}} = qual_fold(F, Acc0, [], FormsNoShadows, State), FunctionNames = [Name || {function, _, Name, _, _} <- FormsNoShadows], UniqueFName = qlc:aux_name(used_genvar, 1, sets:from_list(FunctionNames)), {function,0,UniqueFName,0,[{clause,0,[],[],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) -> IntroVars = intro_variables(FormsNoShadows, State), 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), QCode = qcode(OrigE, XQCs, Source, L), 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) 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), {restore_line_numbers(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),[{abs(LcL),?APIMOD,too_complex_join}]}]}; EqualCols2 =:= [], MatchCols2 =:= [] -> {[], []}; length(Tables) > 2 -> {[], [{get(?QLC_FILE),[{abs(LcL),?APIMOD,too_many_joins}]}]}; EqualCols2 =:= MatchCols2 -> {EqualCols2, []}; true -> {{EqualCols2, MatchCols2}, []} end. qlc_kind(OrigE, Qs) -> {OrigFilterData, OrigGeneratorData} = qual_data(undo_no_shadows(Qs)), 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(set_line(Filter, 0), Frames, BindFun, State, Imported) of [] -> {[], [{get(?QLC_FILE), [{abs_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), [{abs_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, Line) -> erl_parse:abstract(Term, Line). %% 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]}]}}; _ -> G0 = [begin Call = {call,0,{atom,0,element},[{integer,0,Col},O]}, list2op([{op,0,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) -> ColCls0 = [begin true = Vs0 =/= [], % at least one value to look up Vs1 = list2cons(Vs0), Fils1 = {tuple,0,[{atom,0,FTag}, lists:foldr (fun(F, A) -> {cons,0,{integer,0,F},A} end, {nil,0}, 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,0,[{atom,0,Tag},Vs1,Fils1]}, {clause,0,[erl_parse:abstract(Col)],[],[Vs]} end || {{CIdNo,Col}, Vs0, {FTag,Fils}} <- Columns, CIdNo =:= QualifierNumber] ++ [{clause,0,[{var,0,'_'}],[],[{atom,0,false}]}], ColCls = set_line(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 = 0, 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,0}}}. 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,0,true}} || {GId,{gen,Pattern,_}} <- GeneratorData, lists:member(GId, NoFilterGIds)], E = {nil, 0}, 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,0,'_'}, 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, 0, 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 = 0, {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(set_line(Fil, 0), 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(set_line(Fil, 0), 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 = set_line(filters_as_one(FilterList), 0), 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 = set_line(P1, 0), {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). set_line(T, L) -> map_lines(fun(_L) -> L 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,0,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(sublist(Vars, PatSz), 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() || _ <- seq(1, N)]. pat_tuple(Sz, Vars) when is_integer(Sz), Sz > 0 -> TupleTail = unique_var(), {cons_tuple, list2cons(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,0,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) -> Call = {call,0,{atom,0,element},[{integer,0,Col}, {var,0,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 -> 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({call,L1,{atom,_,element}=E,As}, F0, BF, Imported) -> %% erl_expand_records should add "erlang:"... element_calls({call,L1,{remote,L1,{atom,L1,erlang},E}, As}, F0, 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, 0, make_ref()}. is_unique_var({var, _L, V}) -> is_reference(V). expand_pattern_records(P, State) -> E = {'case',0,{atom,0,true},[{clause,0,[P],[],[{atom,0,true}]}]}, {'case',_,_,[{clause,0,[NP],_,_}]} = expand_expr_records(E, State), NP. expand_expr_records(E, State) -> RecordDefs = State#state.records, Forms = RecordDefs ++ [{function,1,foo,0,[{clause,1,[],[],[pe(E)]}]}], [{function,_,foo,0,[{clause,_,[],[],[NE]}]}] = erl_expand_records:module(Forms, [no_strict_record_tests]), 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, 0, E, list2cons(Es)}; list2cons([]) -> {nil, 0}; list2cons(E) -> E. %% Returns {..., Variable} if Variable is a tuple tail. cons2tuple({cons_tuple, Es}) -> {tuple, 0, 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 = 1, Fun = {'fun',L,{clauses,[{clause,L,[P],[[Fltr]],[E]}]}}, Expr = {call,L,{remote,L,{atom,L,ets},{atom,L,fun2ms}},[Fun]}, Form0 = {function,L,foo,0,[{clause,L,[],[],[Expr]}]}, Form = restore_line_numbers(Form0), 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, 0, true}; filters_as_one(FilterData) -> [{_,{fil,Filter1}} | Filters] = lists:reverse(FilterData), lists:foldr(fun({_QId,{fil,Filter}}, AbstF) -> {op,0,'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) -> list2cons([{tuple,0,[{integer,0,Col},list2cons(qcon1(ConstOps))]} || {Col,ConstOps} <- Cs]). qcon1(ConstOps) -> [{tuple,0,[Const,abstr(Op, 0)]} || {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) -> 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)])], {'fun', L, {clauses, [{clause, L, [], [], [{tuple, L, CL}]}]}}. qcode([{_QId, {_QIvs, {{gen,P,_LE,_GV}, GoI, _SI}}} | QCs], Source) -> [{GoI,undo_no_shadows(P)} | qcode(QCs, Source)]; qcode([{QId, {_QIVs, {{fil,_F}, GoI, _SI}}} | QCs], Source) -> {ok,OrigF} = dict:find(QId, Source), [{GoI,undo_no_shadows(OrigF)} | qcode(QCs, Source)]; qcode([], _Source) -> []. closure(Code, L) -> {'fun',L,{clauses,[{clause,L,[],[],[Code]}]}}. simple(L, Var, Init, Line) -> {tuple,L,[?A(simple_v1),?A(Var),Init,?I(Line)]}. 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) -> erl_parse:set_line(L, fun(Line) -> -abs(Line) end). abs_loc(L) -> loc(erl_parse:set_line(L, fun(Line) -> abs(Line) end)). loc(L) -> {location,Location} = erl_parse:get_attribute(L, location), Location. list2op([E], _Op) -> E; list2op([E | Es], Op) -> {op,0,Op,E,list2op(Es, Op)}. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 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). 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} %% 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 the line number %% position of the abstract code: {var, {nos, OriginalName, L}, %% NewName}. undo_no_shadows/1 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, []}, _ = 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}, {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}=S) when V =/= '_' -> case used_var(V, Vs, UV) of {true, VN} -> NL = nos_var(L, V), {{var,NL,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}, 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, NL = nos_var(L, V), {{var,NL,Name}, {LI,Vs,UV,A,Sg}, 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(L, Name) -> erl_parse:set_line(L, fun(Line) -> {nos,Name,Line} 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) -> var_map(fun undo_no_shadows1/1, E). undo_no_shadows1({var, L, _}=Var) -> case erl_parse:get_attribute(L, line) of {line,{nos,V,_VL}} -> NL = erl_parse:set_line(L, fun({nos,_V,VL}) -> VL end), undo_no_shadows1({var, NL, V}); _Else -> Var end. restore_line_numbers(E) -> var_map(fun restore_line_numbers1/1, E). restore_line_numbers1({var, L, V}=Var) -> case erl_parse:get_attribute(L, line) of {line,{nos,_,_}} -> NL = erl_parse:set_line(L, fun({nos,_V,VL}) -> VL end), restore_line_numbers1({var, NL, V}); _Else -> Var end. %% QLC identifier. %% The first one encountered in the file has No=1. make_lcid(Attrs, No) when is_integer(No), No > 0 -> F = fun(Line) when is_integer(Line), Line < (1 bsl ?MAX_NUM_OF_LINES) -> sgn(Line) * ((No bsl ?MAX_NUM_OF_LINES) + sgn(Line) * Line) end, erl_parse:set_line(Attrs, F). is_lcid(Attrs) -> try {line,Id} = erl_parse:get_attribute(Attrs, line), is_integer(Id) andalso (abs(Id) > (1 bsl ?MAX_NUM_OF_LINES)) catch _:_ -> false end. get_lcid_no(IdAttrs) -> {line,Id} = erl_parse:get_attribute(IdAttrs, line), abs(Id) bsr ?MAX_NUM_OF_LINES. get_lcid_line(IdAttrs) -> {line,Id} = erl_parse:get_attribute(IdAttrs, line), sgn(Id) * (abs(Id) band ((1 bsl ?MAX_NUM_OF_LINES) - 1)). sgn(X) when X >= 0 -> 1; sgn(X) when X < 0 -> -1. seq(S, E) when S - E =:= 1 -> []; seq(S, E) -> lists:seq(S, E). sublist(_, 0) -> []; sublist(L, N) -> lists:sublist(L, N). 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}. 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.