Re: Variable substitution in jsonb functions fails for jsonpath operator like_regex

Erwin Brandstetter <brsaweda(at)gmail(dot)com> writes:
> The functions jsonb_path_exists() and friends accept a "vars" parameter for
> parameter substitution in the jsonpath argument. This seems to work for all
> jsonpath operators except "like_regex":

> SELECT * FROM tbl
> WHERE jsonb_path_exists(data, '$[*].value ? (@ like_regex $foo)', '{"foo":
> "CEO"}');

>> ERROR: syntax error at or near "$foo" of jsonpath input
>> LINE 3: WHERE jsonb_path_exists(data, '$[*].value ? (@ like_regex $...

> Notably, the same works even for "starts with":

Hmm, maybe just an oversight in jsonpath_gram.y?

predicate:
...
| expr STARTS_P WITH_P starts_with_initial
| expr LIKE_REGEX_P STRING_P
| expr LIKE_REGEX_P STRING_P FLAG_P STRING_P
;

starts_with_initial:
STRING_P { $$ = makeItemString(&$1); }
| VARIABLE_P { $$ = makeItemVariable(&$1); }
;

Maybe it wouldn't take more than s/STRING_P/starts_with_initial/
here (though I'd then rename starts_with_initial to something
more generic). With bad luck there might be some dependency on
this restriction downstream of the grammar, but I suspect not.
Didn't try though.

regards, tom lane