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Richard Carlsson
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%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2013. 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(pmod_pt).
-export([parse_transform/2,
format_error/1]).
%% Expand function definition forms of parameterized module.
%% The code is based on the code in sys_expand_pmod which used to be
%% included in the compiler, but details are different because
%% sys_pre_expand has not been run. In particular:
%%
%% * Record definitions are still present and must be handled.
%%
%% * (Syntatic) local calls may actually be calls to an imported
%% funtion or a BIF. It is a local call if and only if there
%% is a definition for the function in the module.
%%
%% * When we introduce the module parameters and 'THIS' in each
%% function, we must artificially use it to avoid a warning for
%% unused variables.
%%
%% * On the other hand, we don't have to worry about module_info/0,1
%% because they have not been added yet.
-record(pmod, {parameters,
defined
}).
parse_transform(Forms0, _Options) ->
put(?MODULE, []),
Forms = transform(Forms0),
case erase(?MODULE) of
[] ->
Forms;
[_|_]=Errors ->
File = get_file(Forms),
{error,[{File,Errors}],[]}
end.
format_error(extends_self) ->
"cannot extend from self";
format_error(define_instance) ->
"defining instance function not allowed in parameterized module".
add_error(Line, Error) ->
put(?MODULE, get(?MODULE) ++ [{Line,?MODULE,Error}]).
get_file([{attribute,_,file,{File,_}}|_]) -> File;
get_file([_|T]) -> get_file(T).
transform(Forms0) ->
Def = collect_defined(Forms0),
{Base,ModAs,Forms1} = attribs(Forms0, [], undefined, []),
{Mod,Ps0} = case ModAs of
{M0,P0} -> {M0,P0};
M0 -> {M0,undefined}
end,
Forms2 = case Ps0 of
undefined ->
Forms1;
_ ->
pmod_expand(Forms1, Mod, Base, Ps0, Def)
end,
%% Add new functions.
NewFs0 = maybe_extend(Base, Mod, Ps0),
NewExps = collect_defined(NewFs0),
Forms3 = add_attributes(Forms2, [{attribute,0,export,NewExps}]),
add_new_funcs(Forms3, NewFs0).
pmod_expand(Forms0, Mod, Base, Ps0, Def) ->
Ps = if is_atom(Base) ->
['BASE' | Ps0];
true ->
Ps0
end,
St0 = #pmod{parameters=Ps,defined=gb_sets:from_list(Def)},
{Forms1,_} = forms(Forms0, St0),
Forms2 = update_exps(Forms1),
Forms3 = update_forms(Forms2),
NewFs0 = add_instance(Mod, Ps, []),
NewFs = ensure_new(Base, Ps0, NewFs0),
Forms = add_new_funcs(Forms3, NewFs),
NewExps = collect_defined(NewFs),
add_attributes(Forms, [{attribute,0,export,NewExps}]).
add_attributes([{attribute,_,module,_}=F|Fs], Attrs) ->
[F|Attrs++Fs];
add_attributes([F|Fs], Attrs) ->
[F|add_attributes(Fs, Attrs)].
add_new_funcs([{eof,_}|_]=Fs, NewFs) ->
NewFs ++ Fs;
add_new_funcs([F|Fs], Es) ->
[F|add_new_funcs(Fs, Es)];
add_new_funcs([], NewFs) ->
NewFs.
maybe_extend([], _, _) ->
%% No 'extends' attribute.
[];
maybe_extend(Base, _Mod, undefined) ->
%% There is a an 'extends' attribute; the module is not parameterized.
Name = '$handle_undefined_function',
Args = [{var,0,'Func'},{var,0,'Args'}],
Body = [make_apply({atom,0,Base}, {var,0,'Func'}, {var,0,'Args'})],
F = {function,0,Name,2,[{clause,0,Args,[],Body}]},
[F];
maybe_extend(Base, Mod, Ps) ->
%% There is a an 'extends' attribute; the module is parameterized.
Name = '$handle_undefined_function',
Args = [{var,0,'Func'},{var,0,'Args'}],
DontCares = [{var,0,'_'} || _ <- Ps],
TuplePs = {tuple,0,[{atom,0,Mod},{var,0,'BaseVars'}|DontCares]},
G = [{call,0,{atom,0,is_atom},
[{call,0,{atom,0,element},
[{integer,0,1},{var,0,'BaseVars'}]}]}],
FixedArgs = make_lists_rev([{var,0,'Rs'},
{cons,0,{var,0,'BaseVars'},{nil,0}}]),
Body = [{'case',0,make_lists_rev([{var,0,'Args'}]),
[{clause,0,[{cons,0,TuplePs,{var,0,'Rs'}}],[G],
[make_apply({atom,0,Base}, {var,0,'Func'}, FixedArgs)]},
{clause,0,[{var,0,'_'}],[],
[make_apply({atom,0,Base}, {var,0,'Func'}, {var,0,'Args'})]}
]}],
F = {function,0,Name,2,[{clause,0,Args,[],Body}]},
[F].
make_apply(M, F, A) ->
{call,0,{remote,0,{atom,0,erlang},{atom,0,apply}},[M,F,A]}.
make_lists_rev(As) ->
{call,0,{remote,0,{atom,0,lists},{atom,0,reverse}},As}.
ensure_new(Base, Ps, Fs) ->
case has_new(Fs) of
true ->
Fs;
false ->
add_new(Base, Ps, Fs)
end.
has_new([{function,_L,new,_A,_Cs} | _Fs]) ->
true;
has_new([_ | Fs]) ->
has_new(Fs);
has_new([]) ->
false.
add_new(Base, Ps, Fs) ->
Vs = [{var,0,V} || V <- Ps],
As = if is_atom(Base) ->
[{call,0,{remote,0,{atom,0,Base},{atom,0,new}},Vs} | Vs];
true ->
Vs
end,
Body = [{call,0,{atom,0,instance},As}],
add_func(new, Vs, Body, Fs).
add_instance(Mod, Ps, Fs) ->
Vs = [{var,0,V} || V <- Ps],
AbsMod = [{tuple,0,[{atom,0,Mod}|Vs]}],
add_func(instance, Vs, AbsMod, Fs).
add_func(Name, Args, Body, Fs) ->
A = length(Args),
F = {function,0,Name,A,[{clause,0,Args,[],Body}]},
[F|Fs].
collect_defined(Fs) ->
[{N,A} || {function,_,N,A,_} <- Fs].
attribs([{attribute,Line,module,{Mod,_}=ModAs}|T], Base, _, Acc) ->
attribs(T, Base, ModAs, [{attribute,Line,module,Mod}|Acc]);
attribs([{attribute,_,module,Mod}=H|T], Base, _, Acc) ->
attribs(T, Base, Mod, [H|Acc]);
attribs([{attribute,Line,extends,Base}|T], Base0, Ps, Acc) when is_atom(Base) ->
Mod = case Ps of
{Mod0,_} -> Mod0;
Mod0 -> Mod0
end,
case Mod of
Base ->
add_error(Line, extends_self),
attribs(T, Base0, Ps, Acc);
_ ->
attribs(T, Base, Ps, Acc)
end;
attribs([H|T], Base, Ps, Acc) ->
attribs(T, Base, Ps, [H|Acc]);
attribs([], Base, Ps, Acc) ->
{Base,Ps,lists:reverse(Acc)}.
%% This is extremely simplistic for now; all functions get an extra
%% parameter, whether they need it or not, except for static functions.
update_function_name({F,A}) when F =/= new ->
{F,A+1};
update_function_name(E) ->
E.
update_forms([{function,L,N,A,Cs}|Fs]) when N =/= new ->
[{function,L,N,A+1,Cs}|update_forms(Fs)];
update_forms([F|Fs]) ->
[F|update_forms(Fs)];
update_forms([]) ->
[].
update_exps([{attribute,Line,export,Es0}|T]) ->
Es = [update_function_name(E) || E <- Es0],
[{attribute,Line,export,Es}|update_exps(T)];
update_exps([H|T]) ->
[H|update_exps(T)];
update_exps([]) ->
[].
%% Process the program forms.
forms([F0|Fs0],St0) ->
{F1,St1} = form(F0,St0),
{Fs1,St2} = forms(Fs0,St1),
{[F1|Fs1],St2};
forms([], St0) ->
{[], St0}.
%% Only function definitions are of interest here. State is not updated.
form({function,Line,instance,_Arity,_Clauses}=F,St) ->
add_error(Line, define_instance),
{F,St};
form({function,Line,Name0,Arity0,Clauses0},St) when Name0 =/= new ->
{Name,Arity,Clauses} = function(Name0, Arity0, Clauses0, St),
{{function,Line,Name,Arity,Clauses},St};
%% Pass anything else through
form(F,St) -> {F,St}.
function(Name, Arity, Clauses0, St) ->
Clauses1 = clauses(Clauses0,St),
{Name,Arity,Clauses1}.
clauses([C|Cs],#pmod{parameters=Ps}=St) ->
{clause,L,H,G,B0} = clause(C,St),
T = {tuple,L,[{var,L,V} || V <- ['_'|Ps]]},
B = [{match,L,{var,L,'_'},{var,L,V}} || V <- ['THIS'|Ps]] ++ B0,
[{clause,L,H++[{match,L,T,{var,L,'THIS'}}],G,B}|clauses(Cs,St)];
clauses([],_St) -> [].
clause({clause,Line,H,G,B0},St) ->
%% We never update H and G, so we will just copy them.
B1 = exprs(B0,St),
{clause,Line,H,G,B1}.
pattern_grp([{bin_element,L1,E1,S1,T1} | Fs],St) ->
S2 = case S1 of
default ->
default;
_ ->
expr(S1,St)
end,
T2 = case T1 of
default ->
default;
_ ->
bit_types(T1)
end,
[{bin_element,L1,expr(E1,St),S2,T2} | pattern_grp(Fs,St)];
pattern_grp([],_St) ->
[].
bit_types([]) ->
[];
bit_types([Atom | Rest]) when is_atom(Atom) ->
[Atom | bit_types(Rest)];
bit_types([{Atom, Integer} | Rest]) when is_atom(Atom), is_integer(Integer) ->
[{Atom, Integer} | bit_types(Rest)].
exprs([E0|Es],St) ->
E1 = expr(E0,St),
[E1|exprs(Es,St)];
exprs([],_St) -> [].
expr({var,_L,_V}=Var,_St) ->
Var;
expr({integer,_Line,_I}=Integer,_St) -> Integer;
expr({float,_Line,_F}=Float,_St) -> Float;
expr({atom,_Line,_A}=Atom,_St) -> Atom;
expr({string,_Line,_S}=String,_St) -> String;
expr({char,_Line,_C}=Char,_St) -> Char;
expr({nil,_Line}=Nil,_St) -> Nil;
expr({cons,Line,H0,T0},St) ->
H1 = expr(H0,St),
T1 = expr(T0,St),
{cons,Line,H1,T1};
expr({lc,Line,E0,Qs0},St) ->
Qs1 = lc_bc_quals(Qs0,St),
E1 = expr(E0,St),
{lc,Line,E1,Qs1};
expr({bc,Line,E0,Qs0},St) ->
Qs1 = lc_bc_quals(Qs0,St),
E1 = expr(E0,St),
{bc,Line,E1,Qs1};
expr({tuple,Line,Es0},St) ->
Es1 = expr_list(Es0,St),
{tuple,Line,Es1};
expr({record_index,_,_,_}=RI, _St) ->
RI;
expr({record,Line,Name,Is0},St) ->
Is = record_fields(Is0,St),
{record,Line,Name,Is};
expr({record,Line,E0,Name,Is0},St) ->
E = expr(E0,St),
Is = record_fields(Is0,St),
{record,Line,E,Name,Is};
expr({record_field,Line,E0,Name,Key},St) ->
E = expr(E0,St),
{record_field,Line,E,Name,Key};
expr({block,Line,Es0},St) ->
Es1 = exprs(Es0,St),
{block,Line,Es1};
expr({'if',Line,Cs0},St) ->
Cs1 = icr_clauses(Cs0,St),
{'if',Line,Cs1};
expr({'case',Line,E0,Cs0},St) ->
E1 = expr(E0,St),
Cs1 = icr_clauses(Cs0,St),
{'case',Line,E1,Cs1};
expr({'receive',Line,Cs0},St) ->
Cs1 = icr_clauses(Cs0,St),
{'receive',Line,Cs1};
expr({'receive',Line,Cs0,To0,ToEs0},St) ->
To1 = expr(To0,St),
ToEs1 = exprs(ToEs0,St),
Cs1 = icr_clauses(Cs0,St),
{'receive',Line,Cs1,To1,ToEs1};
expr({'try',Line,Es0,Scs0,Ccs0,As0},St) ->
Es1 = exprs(Es0,St),
Scs1 = icr_clauses(Scs0,St),
Ccs1 = icr_clauses(Ccs0,St),
As1 = exprs(As0,St),
{'try',Line,Es1,Scs1,Ccs1,As1};
expr({'fun',_,{function,_,_,_}}=ExtFun,_St) ->
ExtFun;
expr({'fun',Line,Body},St) ->
case Body of
{clauses,Cs0} ->
Cs1 = fun_clauses(Cs0,St),
{'fun',Line,{clauses,Cs1}};
{function,F,A} = Function ->
{F1,A1} = update_function_name({F,A}),
if A1 =:= A ->
{'fun',Line,Function};
true ->
%% Must rewrite local fun-name to a fun that does a
%% call with the extra THIS parameter.
As = make_vars(A, Line),
As1 = As ++ [{var,Line,'THIS'}],
Call = {call,Line,{atom,Line,F1},As1},
Cs = [{clause,Line,As,[],[Call]}],
{'fun',Line,{clauses,Cs}}
end;
{function,_M,_F,_A} = Fun4 -> %This is an error in lint!
{'fun',Line,Fun4}
end;
expr({call,Lc,{atom,_,instance}=Name,As0},St) ->
%% All local functions 'instance(...)' are static by definition,
%% so they do not take a 'THIS' argument when called
As1 = expr_list(As0,St),
{call,Lc,Name,As1};
expr({call,Lc,{atom,_,new}=Name,As0},St) ->
%% All local functions 'new(...)' are static by definition,
%% so they do not take a 'THIS' argument when called
As1 = expr_list(As0,St),
{call,Lc,Name,As1};
expr({call,Lc,{atom,_Lf,F}=Atom,As0}, #pmod{defined=Def}=St) ->
As1 = expr_list(As0,St),
case gb_sets:is_member({F,length(As0)}, Def) of
false ->
%% BIF or imported function.
{call,Lc,Atom,As1};
true ->
%% Local function call - needs THIS parameter.
{call,Lc,Atom,As1 ++ [{var,0,'THIS'}]}
end;
expr({call,Line,F0,As0},St) ->
%% Other function call
F1 = expr(F0,St),
As1 = expr_list(As0,St),
{call,Line,F1,As1};
expr({'catch',Line,E0},St) ->
E1 = expr(E0,St),
{'catch',Line,E1};
expr({match,Line,P,E0},St) ->
E1 = expr(E0,St),
{match,Line,P,E1};
expr({bin,Line,Fs},St) ->
Fs2 = pattern_grp(Fs,St),
{bin,Line,Fs2};
expr({op,Line,Op,A0},St) ->
A1 = expr(A0,St),
{op,Line,Op,A1};
expr({op,Line,Op,L0,R0},St) ->
L1 = expr(L0,St),
R1 = expr(R0,St),
{op,Line,Op,L1,R1};
%% The following are not allowed to occur anywhere!
expr({remote,Line,M0,F0},St) ->
M1 = expr(M0,St),
F1 = expr(F0,St),
{remote,Line,M1,F1}.
expr_list([E0|Es],St) ->
E1 = expr(E0,St),
[E1|expr_list(Es,St)];
expr_list([],_St) -> [].
record_fields([{record_field,L,K,E0}|T],St) ->
E = expr(E0,St),
[{record_field,L,K,E}|record_fields(T,St)];
record_fields([],_) -> [].
icr_clauses([C0|Cs],St) ->
C1 = clause(C0,St),
[C1|icr_clauses(Cs,St)];
icr_clauses([],_St) -> [].
lc_bc_quals([{generate,Line,P,E0}|Qs],St) ->
E1 = expr(E0,St),
[{generate,Line,P,E1}|lc_bc_quals(Qs,St)];
lc_bc_quals([{b_generate,Line,P,E0}|Qs],St) ->
E1 = expr(E0,St),
[{b_generate,Line,P,E1}|lc_bc_quals(Qs,St)];
lc_bc_quals([E0|Qs],St) ->
E1 = expr(E0,St),
[E1|lc_bc_quals(Qs,St)];
lc_bc_quals([],_St) -> [].
fun_clauses([C0|Cs],St) ->
C1 = clause(C0,St),
[C1|fun_clauses(Cs,St)];
fun_clauses([],_St) -> [].
make_vars(N, L) ->
make_vars(1, N, L).
make_vars(N, M, L) when N =< M ->
V = list_to_atom("X"++integer_to_list(N)),
[{var,L,V} | make_vars(N + 1, M, L)];
make_vars(_, _, _) ->
[].
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