colorful nested (^^gdb) prompt

[Matt Rice <ratmice at gmail dot com>]

attached is the script mentioned here:

http://sourceware.org/ml/gdb-patches/2012-01/msg00619.html

mostly pulled out of
git://gitorious.org/misc-gdb-stuff/misc-gdb-stuff.git
into a single script since I haven't settled on a manner of easily and flexibly
doing explicit loading from .gdbinit (rather than relying on auto-loading).

doesn't work with tui (not sure why, haven't looked), and requires curses.

def go():
  prompt_nest=""
  if os.environ.has_key('GDB_PROMPT_NEST'):
    prompt_nest = os.environ['GDB_PROMPT_NEST']

  # note this is backwards from git's usage of ^
  gdb.execute("set environment GDB_PROMPT_NEST " + prompt_nest + '^')

  nesting_colors = ("blue", "green", "red", "yellow")
  prompt_color = nesting_colors[len(prompt_nest) % len(nesting_colors)]
  prompt_list = [('(', 'normal'), 
		 (prompt_nest, 'normal'),
		 (first_prompt, prompt_color), 
		 (') ', 'normal')]
  # pick one of the following 2 lines...
  gdb.prompt_hook = setup_gaudy_prompt(prompt_list, term_colors())
  #gdb.prompt_hook = setup_gaudy_prompt(prompt_list, no_colors)

import types
import gdb

def ignore_escape_sequence(string):
        return "\001" + string + "\002"

the_very_first_prompt = None
def first_prompt(current):
        global the_very_first_prompt

        if (the_very_first_prompt != None):
          return the_very_first_prompt

        x = current
        y = x.find('(')
        if (y != -1):
          x = x[y + 1 : len(x)]
          y = x.rfind(')')

        if (y != -1):
          x = x[0:y]

        the_very_first_prompt = x
        return the_very_first_prompt

# FIXME fgcolor,color,term_colors are platform specific.
def fgcolor(COLOR):
  return color("setaf", COLOR)

def color(string, COLOR):
  return ignore_escape_sequence(tparm(tigetstr(string), COLOR))

from curses import *
# accepts an option term, term = None is getenv("TERM").
def term_colors(term = None):
  # under gdb sys.stdout doesn't implement fileno()
  # use normal stdout fileno?
  setupterm(term, 1);
  return {
	'black'		: fgcolor(COLOR_BLACK),
	'red'		: fgcolor(COLOR_RED),
	'green'		: fgcolor(COLOR_GREEN),
	'yellow'	: fgcolor(COLOR_YELLOW),
	'blue'		: fgcolor(COLOR_BLUE),
	'magenta'	: fgcolor(COLOR_MAGENTA),
	'cyan'		: fgcolor(COLOR_CYAN),
	'white'		: fgcolor(COLOR_WHITE),
	'normal'	: ignore_escape_sequence(tigetstr("sgr0")),
  }

no_colors = {
	'black'		: "",
	'red'		: "",
	'green'		: "",
	'yellow'	: "",
	'blue'		: "",
	'magenta'	: "",
	'cyan'		: "",
	'white'		: "",
	'normal'	: "", 
}

def string_for_prompt_element(current, e):
	if e[0].__class__ == types.FunctionType:
		return e[0](current)
	else:
		return e[0]

def prompt_recursive(current, alist, colors_dict):
	ret = ""
	for e in alist:
	  if e.__class__ == list:
	    ret += prompt_recursive(current, e, colors_dict)
	  else:	
	    x = string_for_prompt_element(current, e)
	    if (x == None):
	      return ""
	    ret += colors_dict[e[1]] + x + colors_dict['normal']
	return ret

def setup_gaudy_prompt(prompt_stuff, colors_stuff):
  return lambda current: prompt_recursive(current, prompt_stuff, colors_stuff)

go()