$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)
(?: # 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 Sub FindDictTreeNodes(ByVal startAtNodeDict As Scripting.Dictionary, ByVal searchKey As Variant, ByVal searchKeyItem As Variant, _
ByVal result As Collection, Optional ByVal childrenKey As Variant = "Children", Optional ByVal findOnlyFirst As Boolean, _
Optional ByVal searchAtLevel As Integer = 0, Optional ByVal useLikeOperatorForMatching As Boolean = False, _
Optional ByVal nowAtLevel As Integer)
';
$subst = "#CSV list of parameters\n${2}, ${4}, ${6}, ${8}, ${10}, ${12}, ${14}, ${16}, ${18}, ${20}, ${22}, ${24}, ${26}, ${28}, ${30}\n\n#vertical list of parameters\n'${2} - \n'${4} - \n'${6} - \n'${8} - \n'${10} - \n'${12} - \n'${14} - \n'${16} - \n'${18} - \n'${20} - \n'${22} - \n'${24} - \n'${26} - \n'${28} - \n'${30} - \n";
$result = preg_replace($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