[erlang-questions] internal error in lint_module

[Xiao Jia]

Yes you are right!  :-D

I changed it to

        foobar(T, S) -> {erl_syntax:revert(T), S}.

and it works now. Thanks!

On Sun, Jan 19, 2014 at 11:12 PM, Sina Samavati <sina.samv@REDACTED> wrote:
> It is not a bug.
>
> "AST" in parse_transform/2 is a list of abstract forms but the output
> of erl_syntax_lib:mapfold/3 is a syntax tree (namely, that "T1"),
> that's why it throws some errors because parse_transform/2 should
> return a list of abstract forms.
> You can give a *list* of syntax trees to erl_syntax:revert_forms/1 to
> get a *list* of abstract forms.
>
> On Fri, Jan 17, 2014 at 3:26 PM, Xiao Jia <me@REDACTED> wrote:
>> (I posted this to erlang-bugs as well, but it may deserve some
>> discussions here.)
>>
>> I was writing a parse_transform module using erl_syntax_lib:mapfold,
>> but both R16B03 and R15B03-1 give the following error even if the
>> parse_transform module does nothing:
>>
>>
>> z.erl:none: internal error in lint_module;
>> crash reason: {badarg,[{erl_scan,set_attr,
>>                                  [line,function,#Fun<erl_lint.9.103090672>],
>>                                  [{file,"erl_scan.erl"},{line,418}]},
>> ...
>> (see https://gist.github.com/stfairy/8471800 for full error)
>>
>>
>> File z.erl:
>>
>>
>> -module(z).
>> -compile({parse_transform, zt}).
>> -export([f/1]).
>> f(_) -> z.
>>
>>
>> File zt.erl:
>>
>>
>> -module(zt).
>> -export([parse_transform/2]).
>>
>> parse_transform(AST, _Options) ->
>>     [parse(T) || T <- AST].
>>
>> parse({function, _, _, _, _} = T) ->
>>     case erl_syntax_lib:mapfold(fun foobar/2, something, T) of
>>         {T1, _} -> T1;
>>         _ -> T
>>     end;
>> parse(T) -> T.
>>
>> foobar(T, S) -> {T, S}.
>>
>>
>> $ erlc zt.erl
>> $ erlc -pa . z.erl
>>
>>
>>
>> btw, I am a little confused why parse_transform modules are usually
>> named as "zt"...
>>
>>
>> --
>> Regards,
>> Xiao Jia
>> _______________________________________________
>> erlang-questions mailing list
>> erlang-questions@REDACTED
>> http://erlang.org/mailman/listinfo/erlang-questions
>
>
>
> --
> Sina Samavati
> Software engineer
>
> https://github.com/s1n4
> https://twitter.com/sinasamavati



-- 
Regards,
Xiao Jia