%% ``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.
%%
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%%
%% $Id$
%%
-module(erl_id_trans).
%% A identity transformer of Erlang abstract syntax.
%% This module only traverses legal Erlang code. This is most noticeable
%% in guards where only a limited number of expressions are allowed.
%% N.B. if this module is to be used as a basis for tranforms then
%% all the error cases must be handled otherwise this module just crashes!
-export([parse_transform/2]).
parse_transform(Forms, _Options) ->
forms(Forms).
%% forms(Fs) -> lists:map(fun (F) -> form(F) end, Fs).
forms([F0|Fs0]) ->
F1 = form(F0),
Fs1 = forms(Fs0),
[F1|Fs1];
forms([]) -> [].
%% -type form(Form) -> Form.
%% Here we show every known form and valid internal structure. We do not
%% that the ordering is correct!
%% First the various attributes.
form({attribute,Line,module,Mod}) ->
{attribute,Line,module,Mod};
form({attribute,Line,file,{File,Line}}) -> %This is valid anywhere.
{attribute,Line,file,{File,Line}};
form({attribute,Line,export,Es0}) ->
Es1 = farity_list(Es0),
{attribute,Line,export,Es1};
form({attribute,Line,import,{Mod,Is0}}) ->
Is1 = farity_list(Is0),
{attribute,Line,import,{Mod,Is1}};
form({attribute,Line,compile,C}) ->
{attribute,Line,compile,C};
form({attribute,Line,record,{Name,Defs0}}) ->
Defs1 = record_defs(Defs0),
{attribute,Line,record,{Name,Defs1}};
form({attribute,Line,asm,{function,N,A,Code}}) ->
{attribute,Line,asm,{function,N,A,Code}};
form({attribute,Line,Attr,Val}) -> %The general attribute.
{attribute,Line,Attr,Val};
form({function,Line,Name0,Arity0,Clauses0}) ->
{Name,Arity,Clauses} = function(Name0, Arity0, Clauses0),
{function,Line,Name,Arity,Clauses};
% Mnemosyne, ignore...
form({rule,Line,Name,Arity,Body}) ->
{rule,Line,Name,Arity,Body}; % Dont dig into this
%% Extra forms from the parser.
form({error,E}) -> {error,E};
form({warning,W}) -> {warning,W};
form({eof,Line}) -> {eof,Line}.
%% -type farity_list([Farity]) -> [Farity] when Farity <= {atom(),integer()}.
farity_list([{Name,Arity}|Fas]) ->
[{Name,Arity}|farity_list(Fas)];
farity_list([]) -> [].
%% -type record_defs([RecDef]) -> [RecDef].
%% N.B. Field names are full expressions here but only atoms are allowed
%% by the *parser*!
record_defs([{record_field,Line,{atom,La,A},Val0}|Is]) ->
Val1 = expr(Val0),
[{record_field,Line,{atom,La,A},Val1}|record_defs(Is)];
record_defs([{record_field,Line,{atom,La,A}}|Is]) ->
[{record_field,Line,{atom,La,A}}|record_defs(Is)];
record_defs([]) -> [].
%% -type function(atom(), integer(), [Clause]) -> {atom(),integer(),[Clause]}.
function(Name, Arity, Clauses0) ->
Clauses1 = clauses(Clauses0),
{Name,Arity,Clauses1}.
%% -type clauses([Clause]) -> [Clause].
clauses([C0|Cs]) ->
C1 = clause(C0),
[C1|clauses(Cs)];
clauses([]) -> [].
%% -type clause(Clause) -> Clause.
clause({clause,Line,H0,G0,B0}) ->
H1 = head(H0),
G1 = guard(G0),
B1 = exprs(B0),
{clause,Line,H1,G1,B1}.
%% -type head([Pattern]) -> [Pattern].
head(Ps) -> patterns(Ps).
%% -type patterns([Pattern]) -> [Pattern].
%% These patterns are processed "sequentially" for purposes of variable
%% definition etc.
patterns([P0|Ps]) ->
P1 = pattern(P0),
[P1|patterns(Ps)];
patterns([]) -> [].
%% -type pattern(Pattern) -> Pattern.
%% N.B. Only valid patterns are included here.
pattern({var,Line,V}) -> {var,Line,V};
pattern({match,Line,L0,R0}) ->
L1 = pattern(L0),
R1 = pattern(R0),
{match,Line,L1,R1};
pattern({integer,Line,I}) -> {integer,Line,I};
pattern({char,Line,C}) -> {char,Line,C};
pattern({float,Line,F}) -> {float,Line,F};
pattern({atom,Line,A}) -> {atom,Line,A};
pattern({string,Line,S}) -> {string,Line,S};
pattern({nil,Line}) -> {nil,Line};
pattern({cons,Line,H0,T0}) ->
H1 = pattern(H0),
T1 = pattern(T0),
{cons,Line,H1,T1};
pattern({tuple,Line,Ps0}) ->
Ps1 = pattern_list(Ps0),
{tuple,Line,Ps1};
pattern({map,Line,Ps0}) ->
Ps1 = pattern_list(Ps0),
{map,Line,Ps1};
pattern({map_field_exact,Line,K,V}) ->
Ke = expr(K),
Ve = pattern(V),
{map_field_exact,Line,Ke,Ve};
%%pattern({struct,Line,Tag,Ps0}) ->
%% Ps1 = pattern_list(Ps0),
%% {struct,Line,Tag,Ps1};
pattern({record,Line,Name,Pfs0}) ->
Pfs1 = pattern_fields(Pfs0),
{record,Line,Name,Pfs1};
pattern({record_index,Line,Name,Field0}) ->
Field1 = pattern(Field0),
{record_index,Line,Name,Field1};
pattern({record_field,Line,Rec0,Name,Field0}) ->
Rec1 = expr(Rec0),
Field1 = expr(Field0),
{record_field,Line,Rec1,Name,Field1};
pattern({record_field,Line,Rec0,Field0}) ->
Rec1 = expr(Rec0),
Field1 = expr(Field0),
{record_field,Line,Rec1,Field1};
pattern({bin,Line,Fs}) ->
Fs2 = pattern_grp(Fs),
{bin,Line,Fs2};
pattern({op,Line,Op,A}) ->
{op,Line,Op,A};
pattern({op,Line,Op,L,R}) ->
{op,Line,Op,L,R}.
pattern_grp([{bin_element,L1,E1,S1,T1} | Fs]) ->
S2 = case S1 of
default ->
default;
_ ->
expr(S1)
end,
T2 = case T1 of
default ->
default;
_ ->
bit_types(T1)
end,
[{bin_element,L1,expr(E1),S2,T2} | pattern_grp(Fs)];
pattern_grp([]) ->
[].
bit_types([]) ->
[];
bit_types([Atom | Rest]) when atom(Atom) ->
[Atom | bit_types(Rest)];
bit_types([{Atom, Integer} | Rest]) when atom(Atom), integer(Integer) ->
[{Atom, Integer} | bit_types(Rest)].
%% -type pattern_list([Pattern]) -> [Pattern].
%% These patterns are processed "in parallel" for purposes of variable
%% definition etc.
pattern_list([P0|Ps]) ->
P1 = pattern(P0),
[P1|pattern_list(Ps)];
pattern_list([]) -> [].
%% -type pattern_fields([Field]) -> [Field].
%% N.B. Field names are full expressions here but only atoms are allowed
%% by the *linter*!.
pattern_fields([{record_field,Lf,{atom,La,F},P0}|Pfs]) ->
P1 = pattern(P0),
[{record_field,Lf,{atom,La,F},P1}|pattern_fields(Pfs)];
pattern_fields([{record_field,Lf,{var,La,'_'},P0}|Pfs]) ->
P1 = pattern(P0),
[{record_field,Lf,{var,La,'_'},P1}|pattern_fields(Pfs)];
pattern_fields([]) -> [].
%% -type guard([GuardTest]) -> [GuardTest].
guard([G0|Gs]) when list(G0) ->
[guard0(G0) | guard(Gs)];
guard(L) ->
guard0(L).
guard0([G0|Gs]) ->
G1 = guard_test(G0),
[G1|guard0(Gs)];
guard0([]) -> [].
guard_test(Expr={call,Line,{atom,La,F},As0}) ->
case erl_internal:type_test(F, length(As0)) of
true ->
As1 = gexpr_list(As0),
{call,Line,{atom,La,F},As1};
_ ->
gexpr(Expr)
end;
guard_test(Any) ->
gexpr(Any).
%% Before R9, there were special rules regarding the expressions on
%% top level in guards. Those limitations are now lifted - therefore
%% there is no need for a special clause for the toplevel expressions.
%% -type gexpr(GuardExpr) -> GuardExpr.
gexpr({var,Line,V}) -> {var,Line,V};
gexpr({integer,Line,I}) -> {integer,Line,I};
gexpr({char,Line,C}) -> {char,Line,C};
gexpr({float,Line,F}) -> {float,Line,F};
gexpr({atom,Line,A}) -> {atom,Line,A};
gexpr({string,Line,S}) -> {string,Line,S};
gexpr({nil,Line}) -> {nil,Line};
gexpr({map,Line,Map0,Es0}) ->
[Map1|Es1] = gexpr_list([Map0|Es0]),
{map,Line,Map1,Es1};
gexpr({map,Line,Es0}) ->
Es1 = gexpr_list(Es0),
{map,Line,Es1};
gexpr({map_field_assoc,Line,K,V}) ->
Ke = gexpr(K),
Ve = gexpr(V),
{map_field_assoc,Line,Ke,Ve};
gexpr({map_field_exact,Line,K,V}) ->
Ke = gexpr(K),
Ve = gexpr(V),
{map_field_exact,Line,Ke,Ve};
gexpr({cons,Line,H0,T0}) ->
H1 = gexpr(H0),
T1 = gexpr(T0), %They see the same variables
{cons,Line,H1,T1};
gexpr({tuple,Line,Es0}) ->
Es1 = gexpr_list(Es0),
{tuple,Line,Es1};
gexpr({record_index,Line,Name,Field0}) ->
Field1 = gexpr(Field0),
{record_index,Line,Name,Field1};
gexpr({record_field,Line,Rec0,Name,Field0}) ->
Rec1 = gexpr(Rec0),
Field1 = gexpr(Field0),
{record_field,Line,Rec1,Name,Field1};
gexpr({record,Line,Name,Inits0}) ->
Inits1 = grecord_inits(Inits0),
{record,Line,Name,Inits1};
gexpr({call,Line,{atom,La,F},As0}) ->
case erl_internal:guard_bif(F, length(As0)) of
true -> As1 = gexpr_list(As0),
{call,Line,{atom,La,F},As1}
end;
% Guard bif's can be remote, but only in the module erlang...
gexpr({call,Line,{remote,La,{atom,Lb,erlang},{atom,Lc,F}},As0}) ->
case erl_internal:guard_bif(F, length(As0)) or
erl_internal:arith_op(F, length(As0)) or
erl_internal:comp_op(F, length(As0)) or
erl_internal:bool_op(F, length(As0)) of
true -> As1 = gexpr_list(As0),
{call,Line,{remote,La,{atom,Lb,erlang},{atom,Lc,F}},As1}
end;
gexpr({bin,Line,Fs}) ->
Fs2 = pattern_grp(Fs),
{bin,Line,Fs2};
gexpr({op,Line,Op,A0}) ->
case erl_internal:arith_op(Op, 1) or
erl_internal:bool_op(Op, 1) of
true -> A1 = gexpr(A0),
{op,Line,Op,A1}
end;
gexpr({op,Line,Op,L0,R0}) when Op =:= 'andalso'; Op =:= 'orelse' ->
%% R11B: andalso/orelse are now allowed in guards.
L1 = gexpr(L0),
R1 = gexpr(R0), %They see the same variables
{op,Line,Op,L1,R1};
gexpr({op,Line,Op,L0,R0}) ->
case erl_internal:arith_op(Op, 2) or
erl_internal:bool_op(Op, 2) or
erl_internal:comp_op(Op, 2) of
true ->
L1 = gexpr(L0),
R1 = gexpr(R0), %They see the same variables
{op,Line,Op,L1,R1}
end.
%% -type gexpr_list([GuardExpr]) -> [GuardExpr].
%% These expressions are processed "in parallel" for purposes of variable
%% definition etc.
gexpr_list([E0|Es]) ->
E1 = gexpr(E0),
[E1|gexpr_list(Es)];
gexpr_list([]) -> [].
grecord_inits([{record_field,Lf,{atom,La,F},Val0}|Is]) ->
Val1 = gexpr(Val0),
[{record_field,Lf,{atom,La,F},Val1}|grecord_inits(Is)];
grecord_inits([{record_field,Lf,{var,La,'_'},Val0}|Is]) ->
Val1 = gexpr(Val0),
[{record_field,Lf,{var,La,'_'},Val1}|grecord_inits(Is)];
grecord_inits([]) -> [].
%% -type exprs([Expression]) -> [Expression].
%% These expressions are processed "sequentially" for purposes of variable
%% definition etc.
exprs([E0|Es]) ->
E1 = expr(E0),
[E1|exprs(Es)];
exprs([]) -> [].
%% -type expr(Expression) -> Expression.
expr({var,Line,V}) -> {var,Line,V};
expr({integer,Line,I}) -> {integer,Line,I};
expr({float,Line,F}) -> {float,Line,F};
expr({atom,Line,A}) -> {atom,Line,A};
expr({string,Line,S}) -> {string,Line,S};
expr({char,Line,C}) -> {char,Line,C};
expr({nil,Line}) -> {nil,Line};
expr({cons,Line,H0,T0}) ->
H1 = expr(H0),
T1 = expr(T0), %They see the same variables
{cons,Line,H1,T1};
expr({lc,Line,E0,Qs0}) ->
Qs1 = lc_bc_quals(Qs0),
E1 = expr(E0),
{lc,Line,E1,Qs1};
expr({bc,Line,E0,Qs0}) ->
Qs1 = lc_bc_quals(Qs0),
E1 = expr(E0),
{bc,Line,E1,Qs1};
expr({tuple,Line,Es0}) ->
Es1 = expr_list(Es0),
{tuple,Line,Es1};
expr({map,Line,Map0,Es0}) ->
[Map1|Es1] = exprs([Map0|Es0]),
{map,Line,Map1,Es1};
expr({map,Line,Es0}) ->
Es1 = exprs(Es0),
{map,Line,Es1};
expr({map_field_assoc,Line,K,V}) ->
Ke = expr(K),
Ve = expr(V),
{map_field_assoc,Line,Ke,Ve};
expr({map_field_exact,Line,K,V}) ->
Ke = expr(K),
Ve = expr(V),
{map_field_exact,Line,Ke,Ve};
%%expr({struct,Line,Tag,Es0}) ->
%% Es1 = pattern_list(Es0),
%% {struct,Line,Tag,Es1};
expr({record_index,Line,Name,Field0}) ->
Field1 = expr(Field0),
{record_index,Line,Name,Field1};
expr({record,Line,Name,Inits0}) ->
Inits1 = record_inits(Inits0),
{record,Line,Name,Inits1};
expr({record_field,Line,Rec0,Name,Field0}) ->
Rec1 = expr(Rec0),
Field1 = expr(Field0),
{record_field,Line,Rec1,Name,Field1};
expr({record,Line,Rec0,Name,Upds0}) ->
Rec1 = expr(Rec0),
Upds1 = record_updates(Upds0),
{record,Line,Rec1,Name,Upds1};
expr({record_field,Line,Rec0,Field0}) ->
Rec1 = expr(Rec0),
Field1 = expr(Field0),
{record_field,Line,Rec1,Field1};
expr({block,Line,Es0}) ->
%% Unfold block into a sequence.
Es1 = exprs(Es0),
{block,Line,Es1};
expr({'if',Line,Cs0}) ->
Cs1 = icr_clauses(Cs0),
{'if',Line,Cs1};
expr({'case',Line,E0,Cs0}) ->
E1 = expr(E0),
Cs1 = icr_clauses(Cs0),
{'case',Line,E1,Cs1};
expr({'receive',Line,Cs0}) ->
Cs1 = icr_clauses(Cs0),
{'receive',Line,Cs1};
expr({'receive',Line,Cs0,To0,ToEs0}) ->
To1 = expr(To0),
ToEs1 = exprs(ToEs0),
Cs1 = icr_clauses(Cs0),
{'receive',Line,Cs1,To1,ToEs1};
expr({'try',Line,Es0,Scs0,Ccs0,As0}) ->
Es1 = exprs(Es0),
Scs1 = icr_clauses(Scs0),
Ccs1 = icr_clauses(Ccs0),
As1 = exprs(As0),
{'try',Line,Es1,Scs1,Ccs1,As1};
expr({'fun',Line,Body}) ->
case Body of
{clauses,Cs0} ->
Cs1 = fun_clauses(Cs0),
{'fun',Line,{clauses,Cs1}};
{function,F,A} ->
{'fun',Line,{function,F,A}};
{function,M,F,A} when is_atom(M), is_atom(F), is_integer(A) ->
%% R10B-6: fun M:F/A. (Backward compatibility)
{'fun',Line,{function,M,F,A}};
{function,M0,F0,A0} ->
%% R15: fun M:F/A with variables.
M = expr(M0),
F = expr(F0),
A = expr(A0),
{'fun',Line,{function,M,F,A}}
end;
expr({named_fun,Loc,Name,Cs}) ->
{named_fun,Loc,Name,fun_clauses(Cs)};
expr({call,Line,F0,As0}) ->
%% N.B. If F an atom then call to local function or BIF, if F a
%% remote structure (see below) then call to other module,
%% otherwise apply to "function".
F1 = expr(F0),
As1 = expr_list(As0),
{call,Line,F1,As1};
expr({'catch',Line,E0}) ->
%% No new variables added.
E1 = expr(E0),
{'catch',Line,E1};
expr({match,Line,P0,E0}) ->
E1 = expr(E0),
P1 = pattern(P0),
{match,Line,P1,E1};
expr({bin,Line,Fs}) ->
Fs2 = pattern_grp(Fs),
{bin,Line,Fs2};
expr({op,Line,Op,A0}) ->
A1 = expr(A0),
{op,Line,Op,A1};
expr({op,Line,Op,L0,R0}) ->
L1 = expr(L0),
R1 = expr(R0), %They see the same variables
{op,Line,Op,L1,R1};
%% The following are not allowed to occur anywhere!
expr({remote,Line,M0,F0}) ->
M1 = expr(M0),
F1 = expr(F0),
{remote,Line,M1,F1}.
%% -type expr_list([Expression]) -> [Expression].
%% These expressions are processed "in parallel" for purposes of variable
%% definition etc.
expr_list([E0|Es]) ->
E1 = expr(E0),
[E1|expr_list(Es)];
expr_list([]) -> [].
%% -type record_inits([RecordInit]) -> [RecordInit].
%% N.B. Field names are full expressions here but only atoms are allowed
%% by the *linter*!.
record_inits([{record_field,Lf,{atom,La,F},Val0}|Is]) ->
Val1 = expr(Val0),
[{record_field,Lf,{atom,La,F},Val1}|record_inits(Is)];
record_inits([{record_field,Lf,{var,La,'_'},Val0}|Is]) ->
Val1 = expr(Val0),
[{record_field,Lf,{var,La,'_'},Val1}|record_inits(Is)];
record_inits([]) -> [].
%% -type record_updates([RecordUpd]) -> [RecordUpd].
%% N.B. Field names are full expressions here but only atoms are allowed
%% by the *linter*!.
record_updates([{record_field,Lf,{atom,La,F},Val0}|Us]) ->
Val1 = expr(Val0),
[{record_field,Lf,{atom,La,F},Val1}|record_updates(Us)];
record_updates([]) -> [].
%% -type icr_clauses([Clause]) -> [Clause].
icr_clauses([C0|Cs]) ->
C1 = clause(C0),
[C1|icr_clauses(Cs)];
icr_clauses([]) -> [].
%% -type lc_bc_quals([Qualifier]) -> [Qualifier].
%% Allow filters to be both guard tests and general expressions.
lc_bc_quals([{generate,Line,P0,E0}|Qs]) ->
E1 = expr(E0),
P1 = pattern(P0),
[{generate,Line,P1,E1}|lc_bc_quals(Qs)];
lc_bc_quals([{b_generate,Line,P0,E0}|Qs]) ->
E1 = expr(E0),
P1 = pattern(P0),
[{b_generate,Line,P1,E1}|lc_bc_quals(Qs)];
lc_bc_quals([E0|Qs]) ->
E1 = expr(E0),
[E1|lc_bc_quals(Qs)];
lc_bc_quals([]) -> [].
%% -type fun_clauses([Clause]) -> [Clause].
fun_clauses([C0|Cs]) ->
C1 = clause(C0),
[C1|fun_clauses(Cs)];
fun_clauses([]) -> [].
