Re: master 361c5fc2d8e 3/3: Support more predicates in tree-sitter search functions

[Yuan Fu]

It seems that you’ve fixes most of the things you mentioned, thanks.

> How is this function robust against deeply nested or circular predicate
> structures?  Shouldn't there be a recursion limit?

Ok, I can add a recursion limit check.

> Please remove the redundant braces.

Is it really necessary? IMHO having the braces is clearer when the statement 
has more than one line.
> 
> ISTM that if `treesit_traverse_validate_predicate' returns false,
> `signal_data' is always initialized.

I like to always initialize variables.

> 
> The initialization of `signal_data' is thus redundant.  In fact, I'm
> pretty sure you could have `treesit_traverse_validate_predicate' return
> Qnil upon success, and a signal upon failure.

Either way should be fine. I’ve been using the current style throughout 
treesit.c.

> 
>>   if (!NILP (process_fn))
>>     CHECK_TYPE (FUNCTIONP (process_fn), Qfunctionp, process_fn);
>> @@ -3595,6 +3718,7 @@ syms_of_treesit (void)
>>   DEFSYM (Qoutdated, "outdated");
>>   DEFSYM (Qhas_error, "has-error");
>>   DEFSYM (Qlive, "live");
>> +  DEFSYM (Qnot, "not");
>> 
>>   DEFSYM (QCanchor, ":anchor");
>>   DEFSYM (QCequal, ":equal");
>> @@ -3619,6 +3743,7 @@ syms_of_treesit (void)
>>  "user-emacs-directory");
>>   DEFSYM (Qtreesit_parser_deleted, "treesit-parser-deleted");
>>   DEFSYM (Qtreesit_pattern_expand, "treesit-pattern-expand");
>> +  DEFSYM (Qtreesit_invalid_predicate, "treesit-invalid-predicate");
>> 
>>   DEFSYM (Qor, "or");
>> 
>> @@ -3646,6 +3771,9 @@ syms_of_treesit (void)
>>   define_error (Qtreesit_parser_deleted,
>> "This parser is deleted and cannot be used",
>> Qtreesit_error);
>> +  define_error (Qtreesit_invalid_predicate,
>> + "Invalid predicate, see TODO for valid forms for a predicate",
>> + Qtreesit_error);
> 
> Shouldn't this be in actual documentation and not etc/TODO?

Oh, that’s not etc/TODO. I’m going to add a variable in treesit.el which would 
document the shape of predicates, then I’ll replace the TODO with the name of 
that variable. At least that’s the plan for now.

Yuan