langgrep

#! /usr/bin/env python

# langgrep: grep for a pattern but only in files written in the
# specified language (as specified by the shebang line).
#
# Copyright 2009 by Akkana Peck.
# Please share, modify and enjoy under the terms of the GPL v2
# or, at your option, any later GPL version.
#
# Bugs: it isn't smart about parsing the grep flags.
# Anything beginning with a - will be considered a flag
# and passed on to grep; the first argument not starting with -
# is taken to be the search pattern, and everything after that
# is the file list.
#

import string, os, sys
import subprocess
import shlex

def Usage():
    print "langgrep lang [grepflags] pattern files"
    print " e.g. langgrep python -w find *"
    sys.exit(0)

def check_file_lang(filename, lang) :
    if os.path.isdir(filename) or not os.path.exists(filename) :
        return False
    try :
        f = open(filename)
        firstline = f.readline(80)
        f.close()
    except IOError, e :
        print "IOError", e
        #print "exc_info is", sys.exc_info()
        sys.exit(1)
        return False

    if firstline[0:2] == "#!" and string.find(firstline, lang) >= 0 :
        return True
    return False

# main()
if len(sys.argv) < 3 :
    Usage()
lang = sys.argv[1]

# After the language, any flag argument plus the grep pattern
# gets appended to args -- these will be the grep args.
patindex = 0
for i in range(2, len(sys.argv)) :
    if sys.argv[i][0] != '-' :
        patindex = i+1
        break
args = sys.argv[2:patindex]

# Now args are the arguments passed to grep;
# the file list, if any, is sys.argv[patindex+1:]
# If no file list, use ~/bin/*
if patindex >= len(sys.argv):
    os.chdir(os.path.join(os.getenv("HOME"), "bin"))
    files = os.listdir(".")
else :
    files = sys.argv[patindex:]

try :
    for fil in files :
        if check_file_lang(fil, lang) :
            #os.system("grep -H" + args + " " + fil)
            arglist = ['grep', '-H']
            arglist.extend(args)
            arglist.append(fil)
            subprocess.call(arglist)

# Try to catch ctrl-C and print a nicer message. This doesn't work, though:
# subprocess.call just terminates the whole process.
except KeyboardInterrupt, e :
    print "Interrupt!"
    sys.exit(1)