Highlight syntax of function names and their arguments in custom mode

Question

I'm trying to create a major mode that handles the following syntax:

  function someName(value1, value2)
    # some contents
  end function

I'm using the following to highlight the keywords function, and end function.

(define-derived-mode my-mode prog-mode "My Mode"
  "Major mode for editing my mode code."
  (setq-local font-lock-defaults
              '(my-mode-font-lock))

How can I target the function name (someName) and its arguments with font lock (value1, value2)?

Answer 1

In my "my-mode-font-lock" function, this is what I ended up using:

; This regexp matches "function someName(", and sets a font face to "someName"
("^[[:space:]]*?sub\\(?:[[:space:]]*\\)?\\([[:word:]]+\\)?\\(?:[^( \t\n]\\)?"
 (1 font-lock-function-name-face)

 ; This starts at the end of the previous regexp
 ; It matches everything up to "," or ")" - whichever comes first
 ; The ".*" is there to allow extra information, such as "someName(value1 as String)"
 ("\\([[:word:]]+\\).*?\\(?:,\\|)\\)"
  (save-excursion
    (goto-char (match-end 0))
    (backward-char)
    (ignore-errors
      (forward-sexp))
    (point))
  ; Once a match was found, it tries the find another, beginning at the end of the last result
  (goto-char (match-end 0))
  (1 font-lock-variable-name-face)))