%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2010. 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(erl_pp).
%%% Pretty printer for Erlang code in the same format as returned from
%%% the parser. It does not always produce pretty code.
-export([form/1,form/2,
attribute/1,attribute/2,function/1,function/2,rule/1,rule/2,
guard/1,guard/2,exprs/1,exprs/2,exprs/3,expr/1,expr/2,expr/3,expr/4]).
-import(lists, [append/1,foldr/3,mapfoldl/3,reverse/1,reverse/2]).
-import(io_lib, [write/1,format/2,write_char/1,write_string/1]).
-import(erl_parse, [inop_prec/1,preop_prec/1,func_prec/0,max_prec/0]).
-define(MAXLINE, 72).
%%%
%%% Exported functions
%%%
form(Thing) ->
form(Thing, none).
form(Thing, Hook) ->
frmt(lform(Thing, Hook)).
attribute(Thing) ->
attribute(Thing, none).
attribute(Thing, Hook) ->
frmt(lattribute(Thing, Hook)).
function(F) ->
function(F, none).
function(F, Hook) ->
frmt(lfunction(F, Hook)).
rule(R) ->
rule(R, none).
rule(R, Hook) ->
frmt(lrule(R, Hook)).
guard(Gs) ->
guard(Gs, none).
guard(Gs, Hook) ->
frmt(lguard(Gs, Hook)).
exprs(Es) ->
exprs(Es, 0, none).
exprs(Es, Hook) ->
exprs(Es, 0, Hook).
exprs(Es, I, Hook) ->
frmt({seq,[],[],[$,],lexprs(Es, Hook)}, I).
expr(E) ->
frmt(lexpr(E, 0, none)).
expr(E, Hook) ->
frmt(lexpr(E, 0, Hook)).
expr(E, I, Hook) ->
frmt(lexpr(E, 0, Hook), I).
expr(E, I, P, Hook) ->
frmt(lexpr(E, P, Hook), I).
%%%
%%% Local functions
%%%
lform({attribute,Line,Name,Arg}, Hook) ->
lattribute({attribute,Line,Name,Arg}, Hook);
lform({function,Line,Name,Arity,Clauses}, Hook) ->
lfunction({function,Line,Name,Arity,Clauses}, Hook);
lform({rule,Line,Name,Arity,Clauses}, Hook) ->
lrule({rule,Line,Name,Arity,Clauses}, Hook);
%% These are specials to make it easier for the compiler.
lform({error,E}, _Hook) ->
leaf(format("~p\n", [{error,E}]));
lform({warning,W}, _Hook) ->
leaf(format("~p\n", [{warning,W}]));
lform({eof,_Line}, _Hook) ->
$\n.
lattribute({attribute,_Line,type,Type}, Hook) ->
[typeattr(type, Type, Hook),leaf(".\n")];
lattribute({attribute,_Line,opaque,Type}, Hook) ->
[typeattr(opaque, Type, Hook),leaf(".\n")];
lattribute({attribute,_Line,spec,Arg}, _Hook) ->
[specattr(Arg),leaf(".\n")];
lattribute({attribute,_Line,Name,Arg}, Hook) ->
[lattribute(Name, Arg, Hook),leaf(".\n")].
lattribute(module, {M,Vs}, _Hook) ->
attr("module",[{var,0,pname(M)},
foldr(fun(V, C) -> {cons,0,{var,0,V},C}
end, {nil,0}, Vs)]);
lattribute(module, M, _Hook) ->
attr("module", [{var,0,pname(M)}]);
lattribute(export, Falist, _Hook) ->
call({var,0,"-export"}, [falist(Falist)], 0, none);
lattribute(import, Name, _Hook) when is_list(Name) ->
attr("import", [{var,0,pname(Name)}]);
lattribute(import, {From,Falist}, _Hook) ->
attr("import",[{var,0,pname(From)},falist(Falist)]);
lattribute(file, {Name,Line}, _Hook) ->
attr("file", [{var,0,format("~p", [Name])},{integer,0,Line}]);
lattribute(record, {Name,Is}, Hook) ->
Nl = leaf(format("-record(~w,", [Name])),
[{first,Nl,record_fields(Is, Hook)},$)];
lattribute(Name, Arg, _Hook) ->
attr(write(Name), [erl_parse:abstract(Arg)]).
typeattr(Tag, {TypeName,Type,Args}, _Hook) ->
{first,leaf("-"++atom_to_list(Tag)++" "),
typed(call({atom,0,TypeName}, Args, 0, none), Type)}.
ltype({ann_type,_Line,[V,T]}) ->
typed(lexpr(V, none), T);
ltype({paren_type,_Line,[T]}) ->
[$(,ltype(T),$)];
ltype({type,_Line,union,Ts}) ->
{seq,[],[],[' |'],ltypes(Ts)};
ltype({type,_Line,list,[T]}) ->
{seq,$[,$],$,,[ltype(T)]};
ltype({type,_Line,nonempty_list,[T]}) ->
{seq,$[,$],[$,],[ltype(T),leaf("...")]};
ltype({type,Line,nil,[]}) ->
lexpr({nil,Line}, 0, none);
ltype({type,Line,tuple,any}) ->
simple_type({atom,Line,tuple}, []);
ltype({type,_Line,tuple,Ts}) ->
tuple_type(Ts, fun ltype/1);
ltype({type,_Line,record,[{atom,_,N}|Fs]}) ->
record_type(N, Fs);
ltype({type,_Line,range,[_I1,_I2]=Es}) ->
expr_list(Es, '..', fun lexpr/2, none);
ltype({type,_Line,binary,[I1,I2]}) ->
binary_type(I1, I2); % except binary()
ltype({type,_Line,'fun',[]}) ->
leaf("fun()");
ltype({type,_,'fun',[{type,_,any},_]}=FunType) ->
[fun_type(['fun',$(], FunType),$)];
ltype({type,_Line,'fun',[{type,_,product,_},_]}=FunType) ->
[fun_type(['fun',$(], FunType),$)];
ltype({type,Line,T,Ts}) ->
simple_type({atom,Line,T}, Ts);
ltype({remote_type,Line,[M,F,Ts]}) ->
simple_type({remote,Line,M,F}, Ts);
ltype({atom,_,T}) ->
leaf(write(T));
ltype(E) ->
lexpr(E, 0, none).
binary_type(I1, I2) ->
B = [[] || {integer,_,0} <- [I1]] =:= [],
U = [[] || {integer,_,0} <- [I2]] =:= [],
P = max_prec(),
E1 = [[leaf("_:"),lexpr(I1, P, none)] || B],
E2 = [[leaf("_:_*"),lexpr(I2, P, none)] || U],
{seq,'<<','>>',[$,],E1++E2}.
record_type(Name, Fields) ->
{first,[record_name(Name)],field_types(Fields)}.
field_types(Fs) ->
tuple_type(Fs, fun field_type/1).
field_type({type,_Line,field_type,[Name,Type]}) ->
typed(lexpr(Name, none), Type).
typed(B, {type,_,union,Ts}) ->
%% Special layout for :: followed by union.
{first,[B,$\s],{seq,[],[],[],union_type(Ts)}};
typed(B, Type) ->
{list,[{cstep,[B,' ::'],ltype(Type)}]}.
union_type([T|Ts]) ->
[[leaf(":: "),ltype(T)] | ltypes(Ts, fun union_elem/1)].
union_elem(T) ->
[leaf(" | "),ltype(T)].
tuple_type(Ts, F) ->
{seq,${,$},[$,],ltypes(Ts, F)}.
specattr({FuncSpec,TypeSpecs}) ->
Func = case FuncSpec of
{F,_A} ->
format("~w", [F]);
{M,F,_A} ->
format("~w:~w", [M, F])
end,
{first,leaf("-spec "),
{list,[{first,leaf(Func),spec_clauses(TypeSpecs)}]}}.
spec_clauses(TypeSpecs) ->
{prefer_nl,[$;],[sig_type(T) || T <- TypeSpecs]}.
sig_type({type,_Line,bounded_fun,[T,Gs]}) ->
guard_type(fun_type([], T), Gs);
sig_type(FunType) ->
fun_type([], FunType).
guard_type(Before, Gs) ->
Gl = {list,[{step,'when',expr_list(Gs, [$,], fun constraint/2, none)}]},
{list,[{step,Before,Gl}]}.
constraint({type,_Line,constraint,[Tag,As]}, _Hook) ->
simple_type(Tag, As).
fun_type(Before, {type,_,'fun',[FType,Ret]}) ->
{first,Before,{step,[type_args(FType),' ->'],ltype(Ret)}}.
type_args({type,_Line,any}) ->
leaf("(...)");
type_args({type,_line,product,Ts}) ->
targs(Ts).
simple_type(Tag, Types) ->
{first,lexpr(Tag, 0, none),targs(Types)}.
targs(Ts) ->
{seq,$(,$),[$,],ltypes(Ts)}.
ltypes(Ts) ->
ltypes(Ts, fun ltype/1).
ltypes(Ts, F) ->
[F(T) || T <- Ts].
attr(Name, Args) ->
call({var,0,format("-~s", [Name])}, Args, 0, none).
pname(['' | As]) ->
[$. | pname(As)];
pname([A]) ->
write(A);
pname([A | As]) ->
[write(A),$.|pname(As)];
pname(A) when is_atom(A) ->
write(A).
falist([]) ->
{nil,0};
falist([{Name,Arity}|Falist]) ->
{cons,0,{var,0,format("~w/~w", [Name,Arity])},falist(Falist)}.
lfunction({function,_Line,Name,_Arity,Cs}, Hook) ->
Cll = nl_clauses(fun (C, H) -> func_clause(Name, C, H) end, $;, Hook, Cs),
[Cll,leaf(".\n")].
func_clause(Name, {clause,Line,Head,Guard,Body}, Hook) ->
Hl = call({atom,Line,Name}, Head, 0, Hook),
Gl = guard_when(Hl, Guard, Hook),
Bl = body(Body, Hook),
{step,Gl,Bl}.
lrule({rule,_Line,Name,_Arity,Cs}, Hook) ->
Cll = nl_clauses(fun (C, H) -> rule_clause(Name, C, H) end, $;, Hook, Cs),
[Cll,leaf(".\n")].
rule_clause(Name, {clause,Line,Head,Guard,Body}, Hook) ->
Hl = call({atom,Line,Name}, Head, 0, Hook),
Gl = guard_when(Hl, Guard, Hook, leaf(" :-")),
Bl = rule_body(Body, Hook),
{step,Gl,Bl}.
rule_body(Es, Hook) ->
lc_quals(Es, Hook).
guard_when(Before, Guard, Hook) ->
guard_when(Before, Guard, Hook, ' ->').
guard_when(Before, Guard, Hook, After) ->
Gl = lguard(Guard, Hook),
[{list,[{step,Before,Gl}]},After].
lguard([E|Es], Hook) when is_list(E) ->
{list,[{step,'when',expr_list([E|Es], [$;], fun guard0/2, Hook)}]};
lguard([E|Es], Hook) -> % before R6
lguard([[E|Es]], Hook);
lguard([], _) ->
[].
guard0(Es, Hook) ->
expr_list(Es, [$,], fun lexpr/2, Hook).
%% body(Before, Es, Hook) -> [Char].
body([E], Hook) ->
lexpr(E, Hook);
body(Es, Hook) ->
{prefer_nl,[$,],lexprs(Es, Hook)}.
lexpr(E, Hook) ->
lexpr(E, 0, Hook).
lexpr({var,_,V}, _, _) when is_integer(V) -> %Special hack for Robert
leaf(format("_~w", [V]));
lexpr({var,_,V}, _, _) -> leaf(format("~s", [V]));
lexpr({char,_,C}, _, _) -> leaf(write_char(C));
lexpr({integer,_,N}, _, _) -> leaf(write(N));
lexpr({float,_,F}, _, _) -> leaf(write(F));
lexpr({atom,_,A}, _, _) -> leaf(write(A));
lexpr({string,_,S}, _, _) -> {string,S};
lexpr({nil,_}, _, _) -> '[]';
lexpr({cons,_,H,T}, _, Hook) ->
list(T, [H], Hook);
lexpr({lc,_,E,Qs}, _Prec, Hook) ->
Lcl = {list,[{step,[lexpr(E, Hook),leaf(" ||")],lc_quals(Qs, Hook)}]},
{list,[{seq,$[,[],[[]],[{force_nl,leaf(" "),[Lcl]}]},$]]};
%% {list,[{step,$[,Lcl},$]]};
lexpr({bc,_,E,Qs}, _Prec, Hook) ->
Lcl = {list,[{step,[lexpr(E, Hook),leaf(" ||")],lc_quals(Qs, Hook)}]},
{list,[{seq,'<<',[],[[]],[{force_nl,leaf(" "),[Lcl]}]},'>>']};
%% {list,[{step,'<<',Lcl},'>>']};
lexpr({tuple,_,Elts}, _, Hook) ->
tuple(Elts, Hook);
%%lexpr({struct,_,Tag,Elts}, _, Hook) ->
%% {first,format("~w", [Tag]),tuple(Elts, Hook)};
lexpr({record_index, _, Name, F}, Prec, Hook) ->
{P,R} = preop_prec('#'),
Nl = record_name(Name),
El = [Nl,$.,lexpr(F, R, Hook)],
maybe_paren(P, Prec, El);
lexpr({record, _, Name, Fs}, Prec, Hook) ->
{P,_R} = preop_prec('#'),
Nl = record_name(Name),
El = {first,Nl,record_fields(Fs, Hook)},
maybe_paren(P, Prec, El);
lexpr({record_field, _, Rec, Name, F}, Prec, Hook) ->
{L,P,R} = inop_prec('#'),
Rl = lexpr(Rec, L, Hook),
Nl = leaf(format("#~w.", [Name])),
El = [Rl,Nl,lexpr(F, R, Hook)],
maybe_paren(P, Prec, El);
lexpr({record, _, Rec, Name, Fs}, Prec, Hook) ->
{L,P,_R} = inop_prec('#'),
Rl = lexpr(Rec, L, Hook),
Nl = record_name(Name),
El = {first,[Rl,Nl],record_fields(Fs, Hook)},
maybe_paren(P, Prec, El);
lexpr({record_field, _, {atom,_,''}, F}, Prec, Hook) ->
{_L,P,R} = inop_prec('.'),
El = [$.,lexpr(F, R, Hook)],
maybe_paren(P, Prec, El);
lexpr({record_field, _, Rec, F}, Prec, Hook) ->
{L,P,R} = inop_prec('.'),
El = [lexpr(Rec, L, Hook),$.,lexpr(F, R, Hook)],
maybe_paren(P, Prec, El);
lexpr({block,_,Es}, _, Hook) ->
{list,[{step,'begin',body(Es, Hook)},'end']};
lexpr({'if',_,Cs}, _, Hook) ->
{list,[{step,'if',if_clauses(Cs, Hook)},'end']};
lexpr({'case',_,Expr,Cs}, _, Hook) ->
{list,[{step,{list,[{step,'case',lexpr(Expr, Hook)},'of']},
cr_clauses(Cs, Hook)},
'end']};
lexpr({'cond',_,Cs}, _, Hook) ->
{list,[{step,leaf("cond"),cond_clauses(Cs, Hook)},'end']};
lexpr({'receive',_,Cs}, _, Hook) ->
{list,[{step,'receive',cr_clauses(Cs, Hook)},'end']};
lexpr({'receive',_,Cs,To,ToOpt}, _, Hook) ->
Al = {list,[{step,[lexpr(To, Hook),' ->'],body(ToOpt, Hook)}]},
{list,[{step,'receive',cr_clauses(Cs, Hook)},
{step,'after',Al},
'end']};
lexpr({'fun',_,{function,F,A}}, _Prec, _Hook) ->
leaf(format("fun ~w/~w", [F,A]));
lexpr({'fun',_,{function,F,A},Extra}, _Prec, _Hook) ->
{force_nl,fun_info(Extra),leaf(format("fun ~w/~w", [F,A]))};
lexpr({'fun',_,{function,M,F,A}}, _Prec, _Hook) ->
leaf(format("fun ~w:~w/~w", [M,F,A]));
lexpr({'fun',_,{clauses,Cs}}, _Prec, Hook) ->
{list,[{first,'fun',fun_clauses(Cs, Hook)},'end']};
lexpr({'fun',_,{clauses,Cs},Extra}, _Prec, Hook) ->
{force_nl,fun_info(Extra),
{list,[{first,'fun',fun_clauses(Cs, Hook)},'end']}};
lexpr({'query',_,Lc}, _Prec, Hook) ->
{list,[{step,leaf("query"),lexpr(Lc, 0, Hook)},'end']};
lexpr({call,_,{remote,_,{atom,_,M},{atom,_,F}=N}=Name,Args}, Prec, Hook) ->
case erl_internal:bif(M, F, length(Args)) of
true ->
call(N, Args, Prec, Hook);
false ->
call(Name, Args, Prec, Hook)
end;
lexpr({call,_,Name,Args}, Prec, Hook) ->
call(Name, Args, Prec, Hook);
lexpr({'try',_,Es,Scs,Ccs,As}, _, Hook) ->
{list,[if
Scs =:= [] ->
{step,'try',body(Es, Hook)};
true ->
{step,{list,[{step,'try',body(Es, Hook)},'of']},
cr_clauses(Scs, Hook)}
end,
if
Ccs =:= [] ->
[];
true ->
{step,'catch',try_clauses(Ccs, Hook)}
end,
if
As =:= [] ->
[];
true ->
{step,'after',body(As, Hook)}
end,
'end']};
lexpr({'catch',_,Expr}, Prec, Hook) ->
{P,R} = preop_prec('catch'),
El = {list,[{step,'catch',lexpr(Expr, R, Hook)}]},
maybe_paren(P, Prec, El);
lexpr({match,_,Lhs,Rhs}, Prec, Hook) ->
{L,P,R} = inop_prec('='),
Pl = lexpr(Lhs, L, Hook),
Rl = lexpr(Rhs, R, Hook),
El = {list,[{cstep,[Pl,' ='],Rl}]},
maybe_paren(P, Prec, El);
lexpr({op,_,Op,Arg}, Prec, Hook) ->
{P,R} = preop_prec(Op),
Ol = leaf(format("~s ", [Op])),
El = [Ol,lexpr(Arg, R, Hook)],
maybe_paren(P, Prec, El);
lexpr({op,_,Op,Larg,Rarg}, Prec, Hook) when Op =:= 'orelse';
Op =:= 'andalso' ->
%% Breaks lines since R12B.
{L,P,R} = inop_prec(Op),
Ll = lexpr(Larg, L, Hook),
Ol = leaf(format("~s", [Op])),
Lr = lexpr(Rarg, R, Hook),
El = {prefer_nl,[[]],[Ll,Ol,Lr]},
maybe_paren(P, Prec, El);
lexpr({op,_,Op,Larg,Rarg}, Prec, Hook) ->
{L,P,R} = inop_prec(Op),
Ll = lexpr(Larg, L, Hook),
Ol = leaf(format("~s", [Op])),
Lr = lexpr(Rarg, R, Hook),
El = {list,[Ll,Ol,Lr]},
maybe_paren(P, Prec, El);
%% Special expressions which are not really legal everywhere.
lexpr({remote,_,M,F}, Prec, Hook) ->
{L,P,R} = inop_prec(':'),
NameItem = lexpr(M, L, Hook),
CallItem = lexpr(F, R, Hook),
maybe_paren(P, Prec, [NameItem,$:,CallItem]);
%% BIT SYNTAX:
lexpr({bin,_,Fs}, _, Hook) ->
bit_grp(Fs, Hook);
%% Special case for straight values.
lexpr({value,_,Val}, _,_) ->
leaf(write(Val));
%% Now do the hook.
lexpr(Other, _Precedence, none) ->
leaf(format("INVALID-FORM:~w:",[Other]));
lexpr(HookExpr, Precedence, {Mod,Func,Eas}) when Mod =/= 'fun' ->
{ehook,HookExpr,Precedence,{Mod,Func,Eas}};
lexpr(HookExpr, Precedence, Func) ->
{hook,HookExpr,Precedence,Func}.
call(Name, Args, Prec, Hook) ->
{F,P} = func_prec(),
Item = {first,lexpr(Name, F, Hook),args(Args, Hook)},
maybe_paren(P, Prec, Item).
fun_info(Extra) ->
leaf(format("% fun-info: ~w", [Extra])).
%% BITS:
bit_grp(Fs, Hook) ->
append([['<<'],
[try
true = Fs =/= [],
S = bin_string(Fs),
true = io_lib:printable_list(S),
{string,S}
catch _:_ ->
bit_elems(Fs, Hook)
end],
['>>']]).
bin_string([]) ->
[];
bin_string([{bin_element,_,{char,_,C},_,_}|Bin]) ->
[C | bin_string(Bin)].
bit_elems(Es, Hook) ->
expr_list(Es, $,, fun bit_elem/2, Hook).
bit_elem({bin_element,_,Expr,Sz,Types}, Hook) ->
P = max_prec(),
VChars = lexpr(Expr, P, Hook),
SChars = if
Sz =/= default ->
[VChars,$:,lexpr(Sz, P, Hook)];
true ->
VChars
end,
if
Types =/= default ->
[SChars,$/|bit_elem_types(Types)];
true ->
SChars
end.
bit_elem_types([T]) ->
[bit_elem_type(T)];
bit_elem_types([T | Rest]) ->
[bit_elem_type(T), $-|bit_elem_types(Rest)].
bit_elem_type({A,B}) ->
[lexpr(erl_parse:abstract(A), none),
$:,
lexpr(erl_parse:abstract(B), none)];
bit_elem_type(T) ->
lexpr(erl_parse:abstract(T), none).
%% end of BITS
record_name(Name) ->
leaf(format("#~w", [Name])).
record_fields(Fs, Hook) ->
tuple(Fs, fun record_field/2, Hook).
record_field({record_field,_,F,Val}, Hook) ->
{L,_P,R} = inop_prec('='),
Fl = lexpr(F, L, Hook),
Vl = lexpr(Val, R, Hook),
{list,[{cstep,[Fl,' ='],Vl}]};
record_field({typed_record_field,{record_field,_,F,Val},Type}, Hook) ->
{L,_P,R} = inop_prec('='),
Fl = lexpr(F, L, Hook),
Vl = typed(lexpr(Val, R, Hook), Type),
{list,[{cstep,[Fl,' ='],Vl}]};
record_field({typed_record_field,Field,Type0}, Hook) ->
Type = remove_undefined(Type0),
typed(record_field(Field, Hook), Type);
record_field({record_field,_,F}, Hook) ->
lexpr(F, 0, Hook).
remove_undefined({type,L,union,[{atom,_,undefined}|T]}) ->
{type,L,union,T};
remove_undefined(T) -> % cannot happen
T.
list({cons,_,H,T}, Es, Hook) ->
list(T, [H|Es], Hook);
list({nil,_}, Es, Hook) ->
proper_list(reverse(Es), Hook);
list(Other, Es, Hook) ->
improper_list(reverse(Es, [Other]), Hook).
%% if_clauses(Clauses, Hook) -> [Char].
%% Print 'if' clauses.
if_clauses(Cs, Hook) ->
clauses(fun if_clause/2, Hook, Cs).
if_clause({clause,_,[],G,B}, Hook) ->
Gl = [guard_no_when(G, Hook),' ->'],
{step,Gl,body(B, Hook)}.
guard_no_when([E|Es], Hook) when is_list(E) ->
expr_list([E|Es], $;, fun guard0/2, Hook);
guard_no_when([E|Es], Hook) -> % before R6
guard_no_when([[E|Es]], Hook);
guard_no_when([], _) -> % cannot happen
leaf("true").
%% cr_clauses(Clauses, Hook) -> [Char].
%% Print 'case'/'receive' clauses.
cr_clauses(Cs, Hook) ->
clauses(fun cr_clause/2, Hook, Cs).
cr_clause({clause,_,[T],G,B}, Hook) ->
El = lexpr(T, 0, Hook),
Gl = guard_when(El, G, Hook),
Bl = body(B, Hook),
{step,Gl,Bl}.
%% try_clauses(Clauses, Hook) -> [Char].
%% Print 'try' clauses.
try_clauses(Cs, Hook) ->
clauses(fun try_clause/2, Hook, Cs).
try_clause({clause,_,[{tuple,_,[{atom,_,throw},V,S]}],G,B}, Hook) ->
El = lexpr(V, 0, Hook),
Sl = stack_backtrace(S, [El], Hook),
Gl = guard_when(Sl, G, Hook),
Bl = body(B, Hook),
{step,Gl,Bl};
try_clause({clause,_,[{tuple,_,[C,V,S]}],G,B}, Hook) ->
Cs = lexpr(C, 0, Hook),
El = lexpr(V, 0, Hook),
CsEl = [Cs,$:,El],
Sl = stack_backtrace(S, CsEl, Hook),
Gl = guard_when(Sl, G, Hook),
Bl = body(B, Hook),
{step,Gl,Bl}.
stack_backtrace({var,_,'_'}, El, _Hook) ->
El;
stack_backtrace(S, El, Hook) ->
El++[$:,lexpr(S, 0, Hook)].
%% fun_clauses(Clauses, Hook) -> [Char].
%% Print 'fun' clauses.
fun_clauses(Cs, Hook) ->
nl_clauses(fun fun_clause/2, [$;], Hook, Cs).
fun_clause({clause,_,A,G,B}, Hook) ->
El = args(A, Hook),
Gl = guard_when(El, G, Hook),
Bl = body(B, Hook),
{step,Gl,Bl}.
%% cond_clauses(Clauses, Hook) -> [Char].
%% Print 'cond' clauses.
cond_clauses(Cs, Hook) ->
clauses(fun cond_clause/2, Hook, Cs).
cond_clause({clause,_,[],[[E]],B}, Hook) ->
{step,[lexpr(E, Hook),' ->'],body(B, Hook)}.
%% nl_clauses(Type, Hook, Clauses) -> [Char].
%% Generic clause printing function (always breaks lines).
nl_clauses(Type, Sep, Hook, Cs) ->
{prefer_nl,Sep,lexprs(Cs, Type, Hook)}.
%% clauses(Type, Hook, Clauses) -> [Char].
%% Generic clause printing function (breaks lines since R12B).
clauses(Type, Hook, Cs) ->
{prefer_nl,[$;],lexprs(Cs, Type, Hook)}.
%% lc_quals(Qualifiers, After, Hook)
%% List comprehension qualifiers (breaks lines since R12B).
lc_quals(Qs, Hook) ->
{prefer_nl,[$,],lexprs(Qs, fun lc_qual/2, Hook)}.
lc_qual({b_generate,_,Pat,E}, Hook) ->
Pl = lexpr(Pat, 0, Hook),
{list,[{step,[Pl,leaf(" <=")],lexpr(E, 0, Hook)}]};
lc_qual({generate,_,Pat,E}, Hook) ->
Pl = lexpr(Pat, 0, Hook),
{list,[{step,[Pl,leaf(" <-")],lexpr(E, 0, Hook)}]};
lc_qual(Q, Hook) ->
lexpr(Q, 0, Hook).
proper_list(Es, Hook) ->
{seq,$[,$],$,,lexprs(Es, Hook)}.
improper_list(Es, Hook) ->
{seq,$[,$],{$,,$|},lexprs(Es, Hook)}.
tuple(L, Hook) ->
tuple(L, fun lexpr/2, Hook).
tuple(Es, F, Hook) ->
{seq,${,$},$,,lexprs(Es, F, Hook)}.
args(As, Hook) ->
{seq,$(,$),[$,],lexprs(As, Hook)}.
expr_list(Es, Sep, F, Hook) ->
{seq,[],[],Sep,lexprs(Es, F, Hook)}.
lexprs(Es, Hook) ->
lexprs(Es, fun lexpr/2, Hook).
lexprs(Es, F, Hook) ->
[F(E, Hook) || E <- Es].
maybe_paren(P, Prec, Expr) when P < Prec ->
[$(,Expr,$)];
maybe_paren(_P, _Prec, Expr) ->
Expr.
leaf(S) ->
{leaf,iolist_size(S),S}.
%%% Do the formatting. Currently nothing fancy. Could probably have
%%% done it in one single pass.
frmt(Item) ->
frmt(Item, 0).
frmt(Item, I) ->
ST = spacetab(),
WT = wordtable(),
{Chars,_Length} = f(Item, I, ST, WT),
[Chars].
%%% What the tags mean:
%%% - C: a character
%%% - [I|Is]: Is follow after I without newline or space
%%% - {list,IPs}: try to put all IPs on one line, if that fails newlines
%%% and indentation are inserted between IPs.
%%% - {first,I,IP2}: IP2 follows after I, and is output with an indentation
%%% updated with the width of I.
%%% - {seq,Before,After,Separator,IPs}: a sequence of Is separated by
%%% Separator. Before is output before IPs, and the indentation of IPs
%%% is updated with the width of Before. After follows after IPs.
%%% - {force_nl,ExtraInfo,I}: fun-info (a comment) forces linebreak before I.
%%% - {prefer_nl,Sep,IPs}: forces linebreak between Is unlesss negative
%%% indentation.
%%% - {string,S}: a string.
%%% - {hook,...}, {ehook,...}: hook expressions.
%%%
%%% list, first, seq, force_nl, and prefer_nl all accept IPs, where each
%%% element is either an item or a tuple {step|cstep,I1,I2}. step means
%%% that I2 is output after linebreak and an incremented indentation.
%%% cstep works similarly, but no linebreak if the width of I1 is less
%%% than the indentation (this is for "A = <expression over several lines>).
f([]=Nil, _I0, _ST, _WT) ->
{Nil,0};
f(C, _I0, _ST, _WT) when is_integer(C) ->
{C,1};
f({leaf,Length,Chars}, _I0, _ST, _WT) ->
{Chars,Length};
f([Item|Items], I0, ST, WT) ->
consecutive(Items, f(Item, I0, ST, WT), I0, ST, WT);
f({list,Items}, I0, ST, WT) ->
f({seq,[],[],[[]],Items}, I0, ST, WT);
f({first,E,Item}, I0, ST, WT) ->
f({seq,E,[],[[]],[Item]}, I0, ST, WT);
f({seq,Before,After,Sep,LItems}, I0, ST, WT) ->
BCharsSize = f(Before, I0, ST, WT),
I = indent(BCharsSize, I0),
CharsSizeL = fl(LItems, Sep, I, After, ST, WT),
{CharsL,SizeL} = unz(CharsSizeL),
{BCharsL,BSizeL} = unz1([BCharsSize]),
Sizes = BSizeL ++ SizeL,
NSepChars = if
is_list(Sep), Sep =/= [] ->
erlang:max(0, length(CharsL)-1);
true ->
0
end,
case same_line(I0, Sizes, NSepChars) of
{yes,Size} ->
Chars = if
NSepChars > 0 -> insert_sep(CharsL, $\s);
true -> CharsL
end,
{BCharsL++Chars,Size};
no ->
{BCharsL++insert_newlines(CharsSizeL, I, ST),
nsz(lists:last(Sizes), I0)}
end;
f({force_nl,_ExtraInfoItem,Item}, I, ST, WT) when I < 0 ->
%% Extra info is a comment; cannot have that on the same line
f(Item, I, ST, WT);
f({force_nl,ExtraInfoItem,Item}, I, ST, WT) ->
f({prefer_nl,[],[ExtraInfoItem,Item]}, I, ST, WT);
f({prefer_nl,Sep,LItems}, I, ST, WT) when I < 0 ->
f({seq,[],[],Sep,LItems}, I, ST, WT);
f({prefer_nl,Sep,LItems}, I0, ST, WT) ->
CharsSize2L = fl(LItems, Sep, I0, [], ST, WT),
{_CharsL,Sizes} = unz(CharsSize2L),
if
Sizes =:= [] ->
{[], 0};
true ->
{insert_newlines(CharsSize2L, I0, ST),nsz(lists:last(Sizes), I0)}
end;
f({string,S}, I, ST, WT) ->
f(write_a_string(S, I), I, ST, WT);
f({hook,HookExpr,Precedence,Func}, I, _ST, _WT) ->
Chars = Func(HookExpr, I, Precedence, Func),
{Chars,indentation(Chars, I)};
f({ehook,HookExpr,Precedence,{Mod,Func,Eas}=ModFuncEas}, I, _ST, _WT) ->
Chars = apply(Mod, Func, [HookExpr,I,Precedence,ModFuncEas|Eas]),
{Chars,indentation(Chars, I)};
f(WordName, _I, _ST, WT) -> % when is_atom(WordName)
word(WordName, WT).
-define(IND, 4).
%% fl(ListItems, I0, ST, WT) -> [[CharsSize1,CharsSize2]]
%% ListItems = [{Item,Items}|Item]
fl([], _Sep, I0, After, ST, WT) ->
[[f(After, I0, ST, WT),{[],0}]];
fl(CItems, Sep0, I0, After, ST, WT) ->
F = fun({step,Item1,Item2}, S) ->
[f(Item1, I0, ST, WT),f([Item2,S], incr(I0, ?IND), ST, WT)];
({cstep,Item1,Item2}, S) ->
{_,Sz1} = CharSize1 = f(Item1, I0, ST, WT),
if
is_integer(Sz1), Sz1 < ?IND ->
Item2p = [leaf("\s"),Item2,S],
[consecutive(Item2p, CharSize1, I0, ST, WT),{[],0}];
true ->
[CharSize1,f([Item2,S], incr(I0, ?IND), ST, WT)]
end;
(Item, S) ->
[f([Item,S], I0, ST, WT),{[],0}]
end,
{Sep,LastSep} = case Sep0 of {_,_} -> Sep0; _ -> {Sep0,Sep0} end,
fl1(CItems, F, Sep, LastSep, After).
fl1([CItem], F, _Sep, _LastSep, After) ->
[F(CItem,After)];
fl1([CItem1,CItem2], F, _Sep, LastSep, After) ->
[F(CItem1, LastSep),F(CItem2, After)];
fl1([CItem|CItems], F, Sep, LastSep, After) ->
[F(CItem, Sep)|fl1(CItems, F, Sep, LastSep, After)].
consecutive(Items, CharSize1, I0, ST, WT) ->
{CharsSizes,_Length} =
mapfoldl(fun(Item, Len) ->
CharsSize = f(Item, Len, ST, WT),
{CharsSize,indent(CharsSize, Len)}
end, indent(CharSize1, I0), Items),
{CharsL,SizeL} = unz1([CharSize1|CharsSizes]),
{CharsL,line_size(SizeL)}.
unz(CharsSizesL) ->
unz1(append(CharsSizesL)).
unz1(CharSizes) ->
lists:unzip(nonzero(CharSizes)).
nonzero(CharSizes) ->
lists:filter(fun({_,Sz}) -> Sz =/= 0 end, CharSizes).
insert_newlines(CharsSizesL, I, ST) when I >= 0 ->
insert_nl(foldr(fun([{_C1,0},{_C2,0}], A) ->
A;
([{C1,_Sz1},{_C2,0}], A) ->
[C1|A];
([{C1,_Sz1},{C2,Sz2}], A) when Sz2 > 0 ->
[insert_nl([C1,C2], I+?IND, ST)|A]
end, [], CharsSizesL), I, ST).
insert_nl(CharsL, I, ST) ->
insert_sep(CharsL, nl_indent(I, ST)).
insert_sep([Chars1 | CharsL], Sep) ->
[Chars1 | [[Sep,Chars] || Chars <- CharsL]].
nl_indent(0, _T) ->
$\n;
nl_indent(I, T) when I > 0 ->
[$\n|spaces(I, T)].
same_line(I0, SizeL, NSepChars) ->
try
Size = lists:sum(SizeL) + NSepChars,
true = incr(I0, Size) =< ?MAXLINE,
{yes,Size}
catch _:_ ->
no
end.
line_size(SizeL) ->
line_size(SizeL, 0, false).
line_size([], Size, false) ->
Size;
line_size([], Size, true) ->
{line,Size};
line_size([{line,Len}|SizeL], _, _) ->
line_size(SizeL, Len, true);
line_size([Sz|SizeL], SizeSoFar, LF) ->
line_size(SizeL, SizeSoFar+Sz, LF).
nsz({line,_Len}=Sz, _I) ->
Sz;
nsz(Size, I) when I >= 0 ->
{line,Size+I}.
indent({_Chars,{line,Len}}, _I) ->
Len;
indent({_Chars,Size}, I) ->
incr(I, Size).
incr(I, _Incr) when I < 0 ->
I;
incr(I, Incr) ->
I+Incr.
indentation(E, I) when I < 0 ->
iolist_size(E);
indentation(E, I0) ->
I = io_lib_format:indentation(E, I0),
case has_nl(E) of
true -> {line,I};
false -> I
end.
has_nl([$\n|_]) ->
true;
has_nl([C|Cs]) when is_integer(C) ->
has_nl(Cs);
has_nl([C|Cs]) ->
has_nl(C) orelse has_nl(Cs);
has_nl([]) ->
false.
-define(MIN_SUBSTRING, 5).
write_a_string(S, I) when I < 0; S =:= [] ->
leaf(write_string(S));
write_a_string(S, I) ->
Len = erlang:max(?MAXLINE-I, ?MIN_SUBSTRING),
{list,write_a_string(S, Len, Len)}.
write_a_string([], _N, _Len) ->
[];
write_a_string(S, N, Len) ->
SS = string:sub_string(S, 1, N),
Sl = write_string(SS),
case (iolist_size(Sl) > Len) and (N > ?MIN_SUBSTRING) of
true ->
write_a_string(S, N-1, Len);
false ->
[leaf(Sl)|write_a_string(lists:nthtail(length(SS), S), Len, Len)]
end.
%%
%% Utilities
%%
-define(N_SPACES, 30).
spacetab() ->
{[_|L],_} = mapfoldl(fun(_, A) -> {A,[$\s|A]}
end, [], lists:seq(0, ?N_SPACES)),
list_to_tuple(L).
spaces(N, T) when N =< ?N_SPACES ->
element(N, T);
spaces(N, T) ->
[element(?N_SPACES, T)|spaces(N-?N_SPACES, T)].
wordtable() ->
L = [begin {leaf,Sz,S} = leaf(W), {S,Sz} end ||
W <- [" ->"," =","<<",">>","[]","after","begin","case","catch",
"end","fun","if","of","receive","try","when"," ::","..",
" |"]],
list_to_tuple(L).
word(' ->', WT) -> element(1, WT);
word(' =', WT) -> element(2, WT);
word('<<', WT) -> element(3, WT);
word('>>', WT) -> element(4, WT);
word('[]', WT) -> element(5, WT);
word('after', WT) -> element(6, WT);
word('begin', WT) -> element(7, WT);
word('case', WT) -> element(8, WT);
word('catch', WT) -> element(9, WT);
word('end', WT) -> element(10, WT);
word('fun', WT) -> element(11, WT);
word('if', WT) -> element(12, WT);
word('of', WT) -> element(13, WT);
word('receive', WT) -> element(14, WT);
word('try', WT) -> element(15, WT);
word('when', WT) -> element(16, WT);
word(' ::', WT) -> element(17, WT);
word('..', WT) -> element(18, WT);
word(' |', WT) -> element(19, WT).
