aboutsummaryrefslogtreecommitdiffstats
path: root/lib/stdlib/examples/erl_id_trans.erl
diff options
context:
space:
mode:
Diffstat (limited to 'lib/stdlib/examples/erl_id_trans.erl')
-rw-r--r--lib/stdlib/examples/erl_id_trans.erl518
1 files changed, 518 insertions, 0 deletions
diff --git a/lib/stdlib/examples/erl_id_trans.erl b/lib/stdlib/examples/erl_id_trans.erl
new file mode 100644
index 0000000000..b63acdd40a
--- /dev/null
+++ b/lib/stdlib/examples/erl_id_trans.erl
@@ -0,0 +1,518 @@
+%% ``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 via the world wide web 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.
+%%
+%% 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({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};
+%% record_field occurs in query expressions
+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({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;
+% Unfortunately, writing calls as {M,F}(...) is also allowed.
+gexpr({call,Line,{tuple,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,{tuple,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({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} -> %R10B-6: fun M:F/A.
+ {'fun',Line,{function,M,F,A}}
+ end;
+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({'query', Line, E0}) ->
+ %% lc expression
+ E = expr(E0),
+ {'query', Line, E};
+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([]) -> [].
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-10 20:03:30 +0000