From acbca8379bdde12612e27f3313a5c73f4db25381 Mon Sep 17 00:00:00 2001 From: Anthony Ramine Date: Sat, 10 Nov 2012 17:06:01 +0100 Subject: EEP 37: Funs with names This adds optional names to fun expressions. A named fun expression is parsed as a tuple `{named_fun,Loc,Name,Clauses}` in erl_parse. If a fun expression has a name, it must be present and be the same in every of its clauses. The function name shadows the environment of the expression shadowing the environment and it is shadowed by the environment of the clauses' arguments. An unused function name triggers a warning unless it is prefixed by _, just as every variable. Variable _ is allowed as a function name. It is not an error to put a named function in a record field default value. When transforming to Core Erlang, the named fun Fun is changed into the following expression: letrec 'Fun'/Arity = fun (Args) -> let = 'Fun'/Arity in Case in 'Fun'/Arity where Args is the list of arguments of 'Fun'/Arity and Case the Core Erlang expression corresponding to the clauses of Fun. This transformation allows us to entirely skip any k_var to k_local transformation in the fun's clauses bodies. --- lib/compiler/src/sys_pre_expand.erl | 14 ++++++-- lib/compiler/src/v3_core.erl | 68 ++++++++++++++++++++++++++----------- 2 files changed, 60 insertions(+), 22 deletions(-) (limited to 'lib/compiler/src') diff --git a/lib/compiler/src/sys_pre_expand.erl b/lib/compiler/src/sys_pre_expand.erl index 7d918a55ed..48d9c16718 100644 --- a/lib/compiler/src/sys_pre_expand.erl +++ b/lib/compiler/src/sys_pre_expand.erl @@ -344,6 +344,8 @@ expr({'receive',Line,Cs0,To0,ToEs0}, St0) -> {{'receive',Line,Cs,To,ToEs},St3}; expr({'fun',Line,Body}, St) -> fun_tq(Line, Body, St); +expr({named_fun,Line,Name,Cs}, St) -> + fun_tq(Line, Cs, St, Name); expr({call,Line,{atom,La,N}=Atom,As0}, St0) -> {As,St1} = expr_list(As0, St0), Ar = length(As), @@ -475,6 +477,11 @@ fun_tq(Lf, {clauses,Cs0}, St0) -> Index = Uniq = 0, {{'fun',Lf,{clauses,Cs1},{Index,Uniq,Fname}},St2}. +fun_tq(Line, Cs0, St0, Name) -> + {Cs1,St1} = fun_clauses(Cs0, St0), + {Fname,St2} = new_fun_name(St1, Name), + {{named_fun,Line,Name,Cs1,{0,0,Fname}},St2}. + fun_clauses([{clause,L,H0,G0,B0}|Cs0], St0) -> {H,St1} = head(H0, St0), {G,St2} = guard(G0, St1), @@ -485,9 +492,12 @@ fun_clauses([], St) -> {[],St}. %% new_fun_name(State) -> {FunName,State}. -new_fun_name(#expand{func=F,arity=A,fcount=I}=St) -> +new_fun_name(St) -> + new_fun_name(St, 'fun'). + +new_fun_name(#expand{func=F,arity=A,fcount=I}=St, FName) -> Name = "-" ++ atom_to_list(F) ++ "/" ++ integer_to_list(A) - ++ "-fun-" ++ integer_to_list(I) ++ "-", + ++ "-" ++ atom_to_list(FName) ++ "-" ++ integer_to_list(I) ++ "-", {list_to_atom(Name),St#expand{fcount=I+1}}. %% pattern_bin([Element], State) -> {[Element],[Variable],[UsedVar],State}. diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl index 33f5015e0b..321cf7af1c 100644 --- a/lib/compiler/src/v3_core.erl +++ b/lib/compiler/src/v3_core.erl @@ -92,7 +92,7 @@ -record(icase, {anno=#a{},args,clauses,fc}). -record(icatch, {anno=#a{},body}). -record(iclause, {anno=#a{},pats,pguard=[],guard,body}). --record(ifun, {anno=#a{},id,vars,clauses,fc}). +-record(ifun, {anno=#a{},id,vars,clauses,fc,name=unnamed}). -record(iletrec, {anno=#a{},defs,body}). -record(imatch, {anno=#a{},pat,guard=[],arg,fc}). -record(iprimop, {anno=#a{},name,args}). @@ -587,7 +587,11 @@ expr({'fun',L,{function,M,F,A}}, St0) -> name=#c_literal{val=make_fun}, args=As},Aps,St1}; expr({'fun',L,{clauses,Cs},Id}, St) -> - fun_tq(Id, Cs, L, St); + fun_tq(Id, Cs, L, St, unnamed); +expr({named_fun,L,'_',Cs,Id}, St) -> + fun_tq(Id, Cs, L, St, unnamed); +expr({named_fun,L,Name,Cs,{Index,Uniq,_Fname}}, St) -> + fun_tq({Index,Uniq,Name}, Cs, L, St, {named, Name}); expr({call,L,{remote,_,M,F},As0}, #core{wanted=Wanted}=St0) -> {[M1,F1|As1],Aps,St1} = safe_list([M,F|As0], St0), Lanno = lineno_anno(L, St1), @@ -842,9 +846,9 @@ bitstr({bin_element,_,E0,Size0,[Type,{unit,Unit}|Flags]}, St0) -> flags=#c_literal{val=Flags}}, Eps ++ Eps2,St2}. -%% fun_tq(Id, [Clauses], Line, State) -> {Fun,[PreExp],State}. +%% fun_tq(Id, [Clauses], Line, State, NameInfo) -> {Fun,[PreExp],State}. -fun_tq({_,_,Name}=Id, Cs0, L, St0) -> +fun_tq({_,_,Name}=Id, Cs0, L, St0, NameInfo) -> Arity = clause_arity(hd(Cs0)), {Cs1,St1} = clauses(Cs0, St0), {Args,St2} = new_vars(Arity, St1), @@ -853,7 +857,7 @@ fun_tq({_,_,Name}=Id, Cs0, L, St0) -> Fc = function_clause(Ps, Anno, {Name,Arity}), Fun = #ifun{anno=#a{anno=Anno}, id=[{id,Id}], %We KNOW! - vars=Args,clauses=Cs1,fc=Fc}, + vars=Args,clauses=Cs1,fc=Fc,name=NameInfo}, {Fun,[],St3}. %% lc_tq(Line, Exp, [Qualifier], Mc, State) -> {LetRec,[PreExp],State}. @@ -1711,13 +1715,18 @@ uexpr(#icase{anno=A,args=As0,clauses=Cs0,fc=Fc0}, Ks, St0) -> Used = union(used_in_any(As1), used_in_any(Cs1)), New = new_in_all(Cs1), {#icase{anno=A#a{us=Used,ns=New},args=As1,clauses=Cs1,fc=Fc1},St3}; -uexpr(#ifun{anno=A,id=Id,vars=As,clauses=Cs0,fc=Fc0}, Ks0, St0) -> +uexpr(#ifun{anno=A0,id=Id,vars=As,clauses=Cs0,fc=Fc0,name=Name}, Ks0, St0) -> Avs = lit_list_vars(As), - Ks1 = union(Avs, Ks0), - {Cs1,St1} = ufun_clauses(Cs0, Ks1, St0), - {Fc1,St2} = ufun_clause(Fc0, Ks1, St1), - Used = subtract(intersection(used_in_any(Cs1), Ks0), Avs), - {#ifun{anno=A#a{us=Used,ns=[]},id=Id,vars=As,clauses=Cs1,fc=Fc1},St2}; + Ks1 = case Name of + unnamed -> Ks0; + {named,FName} -> union(subtract([FName], Avs), Ks0) + end, + Ks2 = union(Avs, Ks1), + {Cs1,St1} = ufun_clauses(Cs0, Ks2, St0), + {Fc1,St2} = ufun_clause(Fc0, Ks2, St1), + Used = subtract(intersection(used_in_any(Cs1), Ks1), Avs), + A1 = A0#a{us=Used,ns=[]}, + {#ifun{anno=A1,id=Id,vars=As,clauses=Cs1,fc=Fc1,name=Name},St2}; uexpr(#iapply{anno=A,op=Op,args=As}, _, St) -> Used = union(lit_vars(Op), lit_list_vars(As)), {#iapply{anno=A#a{us=Used},op=Op,args=As},St}; @@ -2012,15 +2021,24 @@ cexpr(#itry{anno=A,args=La,vars=Vs,body=Lb,evars=Evs,handler=Lh}, As, St0) -> cexpr(#icatch{anno=A,body=Les}, _As, St0) -> {Ces,_Us1,St1} = cexprs(Les, [], St0), %Never export! {#c_catch{body=Ces},[],A#a.us,St1}; -cexpr(#ifun{anno=A,id=Id,vars=Args,clauses=Lcs,fc=Lfc}, _As, St0) -> - {Ccs,St1} = cclauses(Lcs, [], St0), %NEVER export! - {Cfc,St2} = cclause(Lfc, [], St1), - Anno = A#a.anno, - {#c_fun{anno=Id++Anno,vars=Args, - body=#c_case{anno=Anno, - arg=set_anno(core_lib:make_values(Args), Anno), - clauses=Ccs ++ [Cfc]}}, - [],A#a.us,St2}; +cexpr(#ifun{name=unnamed}=Fun, As, St0) -> + cfun(Fun, As, St0); +cexpr(#ifun{anno=#a{us=Us0}=A0,name={named,Name},fc=#iclause{pats=Ps}}=Fun0, + As, St0) -> + case is_element(Name, Us0) of + false -> + cfun(Fun0, As, St0); + true -> + A1 = A0#a{us=del_element(Name, Us0)}, + Fun1 = Fun0#ifun{anno=A1}, + {#c_fun{body=Body}=CFun0,[],Us1,St1} = cfun(Fun1, As, St0), + RecVar = #c_var{name={Name,length(Ps)}}, + Let = #c_let{vars=[#c_var{name=Name}],arg=RecVar,body=Body}, + CFun1 = CFun0#c_fun{body=Let}, + Letrec = #c_letrec{defs=[{RecVar,CFun1}], + body=RecVar}, + {Letrec,[],Us1,St1} + end; cexpr(#iapply{anno=A,op=Op,args=Args}, _As, St) -> {#c_apply{anno=A#a.anno,op=Op,args=Args},[],A#a.us,St}; cexpr(#icall{anno=A,module=Mod,name=Name,args=Args}, _As, St) -> @@ -2047,6 +2065,16 @@ cexpr(Lit, _As, St) -> %%Vs = lit_vars(Lit), {set_anno(Lit, Anno#a.anno),[],Vs,St}. +cfun(#ifun{anno=A,id=Id,vars=Args,clauses=Lcs,fc=Lfc}, _As, St0) -> + {Ccs,St1} = cclauses(Lcs, [], St0), %NEVER export! + {Cfc,St2} = cclause(Lfc, [], St1), + Anno = A#a.anno, + {#c_fun{anno=Id++Anno,vars=Args, + body=#c_case{anno=Anno, + arg=set_anno(core_lib:make_values(Args), Anno), + clauses=Ccs ++ [Cfc]}}, + [],A#a.us,St2}. + %% lit_vars(Literal) -> [Var]. lit_vars(Lit) -> lit_vars(Lit, []). -- cgit v1.2.3