My Haskell Build script

make.py

import os
import sys
import shutil

CC = "ghc"
EXT = '.hs'
BINARY = 'app'
SAME_DIR = True
SRC_DIR = os.path.join(os.getcwd(), 'src')
BUILD_DIR = os.path.join(os.getcwd(), 'build')

if not os.path.exists(BUILD_DIR):
    os.mkdir(BUILD_DIR)
if not os.path.exists(SRC_DIR):
    raise Exception("Source Directory does not exist!")

SOURCES = ' '.join((
    f.split(os.getcwd())[1][1:] if SAME_DIR else f for f in
    (
        os.path.join(root, f)
        for root, _, files in os.walk(SRC_DIR)
        for f in files if f.endswith(EXT)
    )
))

INCLUDES = []
LIBS = ''
FLAGS = '-threaded -feager-blackholing +RTS -N'

INCLUDES = ' '.join(['i' + i for i in INCLUDES])
OUTPUT = ' '.join(['-odir', BUILD_DIR, '-hidir', BUILD_DIR, '-o', BINARY])

def debug(verbose=False):
    flags = '-Wall'
    command = ' '.join([CC, INCLUDES, SOURCES, flags, OUTPUT, LIBS, FLAGS])
    if verbose: print (command)
    os.system(command)
    
def release(verbose=False):
    flags = '-Werror -O2'
    command = ' '.join([CC, INCLUDES, SOURCES, flags, OUTPUT, LIBS, FLAGS])
    if verbose: print (command)
    os.system(command)

def clean(verbose=False):
    if os.path.exists(BUILD_DIR):
        for root, _, files in os.walk(BUILD_DIR):
            for f in files:
                if verbose: print ("Deleting: " + f)
                os.remove(os.path.join(root, f))

if len(sys.argv) > 1:
    if sys.argv[1] == __file__:
        sys.argv = sys.argv[1:]
    task = sys.argv[1].lower()
    verbose = '-v' in sys.argv
    if task == 'debug' or task == 'build':
        debug(verbose)
    elif task == 'release':
        release(verbose)
    elif task == 'clean' or task == 'clear':
        clean(verbose)
    else:
        debug(verbose)
else:
    debug()