Demo/scripts/pp.py

   1 #! /usr/local/bin/python
   2
   3 # Emulate some Perl command line options.
   4 # Usage: pp [-a] [-c] [-d] [-e scriptline] [-F fieldsep] [-n] [-p] [file] ...
   5 # Where the options mean the following:
   6 #   -a            : together with -n or -p, splits each line into list F
   7 #   -c            : check syntax only, do not execute any code
   8 #   -d            : run the script under the debugger, pdb
   9 #   -e scriptline : gives one line of the Python script; may be repeated
  10 #   -F fieldsep   : sets the field separator for the -a option [not in Perl]
  11 #   -n            : runs the script for each line of input
  12 #   -p            : prints the line after the script has run
  13 # When no script lines have been passed, the first file argument
  14 # contains the script.  With -n or -p, the remaining arguments are
  15 # read as input to the script, line by line.  If a file is '-'
  16 # or missing, standard input is read.
  17
  18 # XXX To do:
  19 # - add -i extension option (change files in place)
  20 # - make a single loop over the files and lines (changes effect of 'break')?
  21 # - add an option to specify the record separator
  22 # - except for -n/-p, run directly from the file if at all possible
  23
  24 import sys
  25 import string
  26 import getopt
  27
  28 FS = ''
  29 SCRIPT = []
  30 AFLAG = 0
  31 CFLAG = 0
  32 DFLAG = 0
  33 NFLAG = 0
  34 PFLAG = 0
  35
  36 try:
  37         optlist, ARGS = getopt.getopt(sys.argv[1:], 'acde:F:np')
  38 except getopt.error, msg:
  39         sys.stderr.write(sys.argv[0] + ': ' + msg + '\n')
  40         sys.exit(2)
  41
  42 for option, optarg in optlist:
  43         if option == '-a':
  44                 AFLAG = 1
  45         elif option == '-c':
  46                 CFLAG = 1
  47         elif option == '-d':
  48                 DFLAG = 1
  49         elif option == '-e':
  50                 for line in string.splitfields(optarg, '\n'):
  51                         SCRIPT.append(line)
  52         elif option == '-F':
  53                 FS = optarg
  54         elif option == '-n':
  55                 NFLAG = 1
  56                 PFLAG = 0
  57         elif option == '-p':
  58                 NFLAG = 1
  59                 PFLAG = 1
  60         else:
  61                 print option, 'not recognized???'
  62
  63 if not ARGS: ARGS.append('-')
  64
  65 if not SCRIPT:
  66         if ARGS[0] == '-':
  67                 fp = sys.stdin
  68         else:
  69                 fp = open(ARGS[0], 'r')
  70         while 1:
  71                 line = fp.readline()
  72                 if not line: break
  73                 SCRIPT.append(line[:-1])
  74         del fp
  75         del ARGS[0]
  76         if not ARGS: ARGS.append('-')
  77
  78 if CFLAG:
  79         prologue = ['if 0:']
  80         epilogue = []
  81 elif NFLAG:
  82         # Note that it is on purpose that AFLAG and PFLAG are
  83         # tested dynamically each time through the loop
  84         prologue = [ \
  85                 'LINECOUNT = 0', \
  86                 'for FILE in ARGS:', \
  87                 '   \tif FILE == \'-\':', \
  88                 '   \t   \tFP = sys.stdin', \
  89                 '   \telse:', \
  90                 '   \t   \tFP = open(FILE, \'r\')', \
  91                 '   \tLINENO = 0', \
  92                 '   \twhile 1:', \
  93                 '   \t   \tLINE = FP.readline()', \
  94                 '   \t   \tif not LINE: break', \
  95                 '   \t   \tLINENO = LINENO + 1', \
  96                 '   \t   \tLINECOUNT = LINECOUNT + 1', \
  97                 '   \t   \tL = LINE[:-1]', \
  98                 '   \t   \taflag = AFLAG', \
  99                 '   \t   \tif aflag:', \
 100                 '   \t   \t   \tif FS: F = string.splitfields(L, FS)', \
 101                 '   \t   \t   \telse: F = string.split(L)' \
 102                 ]
 103         epilogue = [ \
 104                 '   \t   \tif not PFLAG: continue', \
 105                 '   \t   \tif aflag:', \
 106                 '   \t   \t   \tif FS: print string.joinfields(F, FS)', \
 107                 '   \t   \t   \telse: print string.join(F)', \
 108                 '   \t   \telse: print L', \
 109                 ]
 110 else:
 111         prologue = ['if 1:']
 112         epilogue = []
 113
 114 # Note that we indent using tabs only, so that any indentation style
 115 # used in 'command' will come out right after re-indentation.
 116
 117 program = string.joinfields(prologue, '\n') + '\n'
 118 for line in SCRIPT:
 119         program = program + ('   \t   \t' + line + '\n')
 120 program = program + (string.joinfields(epilogue, '\n') + '\n')
 121
 122 import tempfile
 123 tfn = tempfile.mktemp()
 124 try:
 125         fp = open(tfn, 'w')
 126         fp.write(program)
 127         fp.close()
 128         if DFLAG:
 129                 import pdb
 130                 pdb.run('execfile(' + `tfn` + ')')
 131         else:
 132                 execfile(tfn)
 133 finally:
 134         import os
 135         try:
 136                 os.unlink(tfn)
 137         except:
 138                 pass