#!/usr/bin/env python3
# encoding: utf-8
# John O'Meara, 2006
# Thomas Nagy, 2006-2018 (ita)

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

import os, re
from waflib import Task, TaskGen
from waflib.Tools import ccroot

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))
	inputs = [a.path_from(tsk.get_cwd()) for a in tsk.inputs]
	if env.FLEX_MSYS:
		inputs = [x.replace(os.sep, '/') for x in inputs]
	lst.extend(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.replace('\r\n', '\n').replace('\r', '\n')) # issue #1207

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

# To support the following:
# bld(features='c', flexflags='-P/foo')
Task.classes['flex'].vars = ['FLEXFLAGS', 'FLEX']
ccroot.USELIB_VARS['c'].add('FLEXFLAGS')
ccroot.USELIB_VARS['cxx'].add('FLEXFLAGS')

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

	if re.search (r"\\msys\\[0-9.]+\\bin\\flex.exe$", conf.env.FLEX[0]):
		# this is the flex shipped with MSYS
		conf.env.FLEX_MSYS = True

