$re = '/(?x)
.+(?:Sub|Function)\ (\w+)\( # method declaration
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
(?: # start of parameter pattern
[\w\W]*?(?<=\b) # parameter may be preceded by ByVal or Optional keywords
([a-z]\w+)+ # parameter starts with a lower case
.*? # parameter may be followed by its type declaration
(?:=\ ([^\,]+)){0,1} # optional parameters may be followed by default value, it is captured to be used in method call
(?:,|\)) # parameter is followed by , or )
){0,1} # end of parameter pattern (may be copy-pasted infinitely to capture all parameters)
/ms';
$str = 'Public Function BrowseToDictTreeNode(ByVal rootNode As Scripting.Dictionary, ByVal browseKey As String, ByVal nodeUrl As String, _
Optional ByVal urlSlash As String = "/", Optional ByVal childrenKey As String = "Children", _
Optional ByVal startAtLevel As Integer = 1) As Scripting.Dictionary
';
$subst = "#Sub call\n$1 $2:=$3, $4:=$5, $6:=$7, $8:=$9, $10:=$11, $12:=$13, $14:=$15, $16:=$17, $18:=$19, $20:=$21, $20:=$21, $22:=$23, $24:=$25\n\n#Function call\n$1($2:=$3, $4:=$5, $6:=$7, $8:=$9, $10:=$11, $12:=$13, $14:=$15, $16:=$17, $18:=$19, $20:=$21, $20:=$21, $22:=$23, $24:=$25)\n\n#Recursive Sub call\n$1 $2:=$2, $4:=$4, $6:=$6, $8:=$8, $10:=$10, $12:=$12, $14:=$14, $16:=$16, $18:=$18, $20:=$20, $22:=$22, $24:=$24, \n\n#Recursive Function call\n$1($2:=$2, $4:=$4, $6:=$6, $8:=$8, $10:=$10, $12:=$12, $14:=$14, $16:=$16, $18:=$18, $20:=$20, $22:=$22, $24:=$24, )";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php