PegJS - match all characters including ) except if ) is the last character

Question

I am writing a PegJS grammar to parse SQL statements. I'm working on splitting a function into function_id(function_args). For function args I want to match all characters including ( and ) except the last ), this being necessary for nested functions.

How do I write a rule to match all characters which includes ) except when ) is the last character in the string.

The grammar is given below

 Function 
 = func_name open_p args close_p

func_name 
= name:[A-Z]+ {return name.join('');}

open_p
= "("

close_p
= ")"

args
= ar:(.*[^)]) {return ar.join('');}

and the test string is

AVG(A + AVG(B + C))

possible duplicate https://stackoverflow.com/questions/17720264/remove-last-comma-from-a-string — full-stack, Aug 09 '18 at 13:32
Why not just remove the last character if it is a `)`? `"AVG(A + AVG(B + C))".replace(/\)$/, '')"` — gargsms, Aug 09 '18 at 13:55
unfortunately the string cant be manipulated as it part of a larger string being parsed in PegJS. Thus only PegJS manipulations are allowed. — Aveer28, Aug 10 '18 at 10:18

Josh Voigts · Accepted Answer · 2018-08-13T14:52:14.260

Rules to handle the arguments correctly can help. Also, instead of using {return name.join('');} you can use $() notation in the rule to combine parsed strings.

args can either be function or nonfunction repeated. nonfunction captures everything that is not a function by look ahead.

function 
 = func_name open_p (args+ / "") close_p

func_name 
= $([A-Z]+)

open_p
= "("

close_p
= ")"

args
= function / nonfunction

nonfunction
= $((!(function / close_p) .)+)

PegJS - match all characters including ) except if ) is the last character

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