Match a pattern not preceded by a quotation mark

Question

I have this pattern (?<!')(\w*)\((\d+|\w+|.*,*)\) that is meant to match strings like:

• c(4)
• hello(54, 41)

Following some answers on SO, I added a negative lookbehind so that if the input string is preceded by a ', the string shouldn't match at all. However, it still partially matches.

For example:

'c(4) returns (4) even though it shouldn't match anything because of the negative lookbehind.

How do I make it so if a string is preceded by ' NOTHING matches?

Answer 1

Since nobody came along, I'll throw this out to get you started.

This regex will match things like

aa(a , sd,,,f,)
aa( as , " ()asdf)) " ,, df, , )
asdf()

but not

'ab(s)

This will fix the basic problem (?<!['\w])\w*
Where (?<!['\w]) will not let the engine skip over a word char just
to satisfy the not quote.
Then the optional words \w* to grab all the words.
And if a 'aaa( quote is before it, then it won't match.

This regex here embellishes what I think you are trying to accomplish
in the function body part of your regex.
It might be a little overwhelming to understand at first.

(?s)(?<!['\w])(\w*)\(((?:,*(?&variable)(?:,+(?&variable))*[,\s]*)?)\)(?(DEFINE)(?<variable>(?:\s*(?:"[^"\\]*(?:\\.[^"\\]*)*"|'[^'\\]*(?:\\.[^'\\]*)*')\s*|[^()"',]+)))

Readable version (via: http://www.regexformat.com)

 (?s)                          # Dot-all modifier

 (?<! ['\w] )                  # Not a quote, nor word behind
                               # <- This will force matching a complete function name
                               #    if it exists, thereby blocking a preceding quote '

 ( \w* )                       # (1), Function name (optional)
 \(
 (                             # (2 start), Function body
      (?:                           # Parameters (optional)
           ,*                            # Comma (optional)
           (?&variable)                  # Function call, get first variable (required)
           (?:                           # More variables (optional)
                ,+                            # Comma  (required)
                (?&variable)                  # Variable (required)
           )*
           [,\s]*                        # Whitespace or comma (optional)
      )?                            # End parameters (optional)
 )                             # (2 end)
 \)

 # Function definitions
 (?(DEFINE)
      (?<variable>                  # (3 start), Function for a single Variable
           (?:
                \s* 
                (?:                           # Double or single quoted string
                     "                            
                     [^"\\]* 
                     (?: \\ . [^"\\]* )*
                     "
                  |  
                     '                      
                     [^'\\]* 
                     (?: \\ . [^'\\]* )*
                     '
                )
                \s*     
             |                              # or,
                [^()"',]+                     # Not quote, paren, comma (can be whitespace)
           )
      )                             # (3 end)
 )