#!/usr/bin/env python
# encoding: utf-8
# John O'Meara, 2006
# Thomas Nagy, 2006-2010 (ita)

"""
The **flex** program is a code generator which creates C or C++ files.
The generated files are compiled into object files.
"""

import waflib.TaskGen

def decide_ext(self, node):
	if 'cxx' in self.features:
		return ['.lex.cc']
	return ['.lex.c']

def flexfun(tsk):
	env = tsk.env
	bld = tsk.generator.bld
	wd = bld.variant_dir
	def to_list(xx):
		if isinstance(xx, str): return [xx]
		return xx
	tsk.last_cmd = lst = []
	lst.extend(to_list(env['FLEX']))
	lst.extend(to_list(env['FLEXFLAGS']))
	lst.extend([a.path_from(bld.bldnode) for a in tsk.inputs])
	lst = [x for x in lst if x]
	txt = bld.cmd_and_log(lst, cwd=wd, env=env.env or None, quiet=0)
	tsk.outputs[0].write(txt)

waflib.TaskGen.declare_chain(
	name = 'flex',
	rule = flexfun, # issue #854
	ext_in = '.l',
	decider = decide_ext,
)

def configure(conf):
	"""
	Detect the *flex* program
	"""
	conf.find_program('flex', var='FLEX')
	conf.env.FLEXFLAGS = ['-t']