[Pyparsing] Function parameters that may have brackets

[happybrowndog <hap...@ho...>]

Hi,

I have been trying to solve this, but just can't figure it out.
I have a function with parameters that I want to parse.  The function is 
of this form:

NUMBERTOSTR(param)
where param is any expression that evaluates to an integer or floating 
point number, for example:
3 + 2
(3 + 2) / 4
((3 + 2) / 4) + 7

param thus can have any number of brackets.

So I coded param using the following pyparsing expression:

param = Forward()
param << ZeroOrMany("(") + Operand + Operator + Operand + 
ZeroOrMany(")") + ZeroOrMany("(") + Optional(param) + ZeroOrMany(")")

and NUMBERTOSTR is coded as follows:

NUMBERTOSTR = Literal("NUMBERTOSTR(") + param + Literal(")")

Here is the problem:
NUMBERTOSTR.parseString("NUMBERTOSTR(( ( (3+2)/4) + 7 ) )")
returns an exception of not being able to find a ")" character.
The reason appears to be that ZeroOrMany(")") consumes all the right 
brackets so that Literal(")") in NUMBERTOSTR is left wanting.

How do I solve this?