#!/usr/bin/env python                 
# 20050429
def usage():
  print ''' 
    Usage: sly.py filename.sly  (Processes sly file.)
           sly.py filename.ly  (Extracts and processes sly files.)
           sly.py --help  (Detailed help.  See below.)

The filename extension is required.  Sly splits filename.sly
vertically into separate files.  The first two bytes are the field
separator.  The next line begins the list of target files terminated
by a field separator at the beginning of a line.  A new line is a
field separator also.

Sly extracts sly-formatted sections from lilypond file filename.ly,
names and creates sly files, and processes them.  The name of the
generated file contains the line number of the source file.

To see detailed help, use a pager: $ sly.py --help | more
or redirect the output to a file:  $ sly.py --help > file.txt
or scroll up with some shells and operating systems.   

(c)2004 David Raleigh Arnold, under GNU. 20050430 '''
  sys.exit(0)

def helpPage():
  print '''

A sly file begins with the field separator of your choice.  Any two
easily typed characters will do, except you can't use white space.
The remainder of the first line is not necessary in a sly file, but in
an embedded file you must give the name of a file to be created.  All
such created files must have the .sly extension to be processed by sly
immediately.

For example, using !! as a separator, a first line could be:

!! (rest of line discarded)

Then there is a list of target files:

!!  (memo ad. lib.)
dummy4.ly !! tpt4.ly !! vlnII4.ly
kazoo4.ly etc...

It is terminated by a field separator at the beginning of a line.

!! Memo
dummy4.ly !! tpt4.ly !! vlnII4.ly
kazoo4.ly
!!

The first data (comment) field immediately follows.  If it is not
empty, it is written to all files.

!! Memo
dummy4.ly !! tpt4.ly !! vlnII4.ly
kazoo4.ly
!! %1 !!

Then fields are written in turn to particular files, but for safety's
sake, sly will not write files if run on a bare header.  A new line
separates fields, unless there is a '%%' at the end of the line.

!!
dummy4.ly !! tpt4.ly !! vlnII4.ly
kazoo4.ly
!!!! dummy notes !! tpt notes !!vlnII notes !! kazoo
!!  dummy notes !! tpt notes !!vlnII notes !! kazoo

or

!!
dummy4.ly !! tpt4.ly !! vlnII4.ly
kazoo4.ly
!!
dummy notes
tpt notes
vlnII notes
kazoo

dummy notes
tpt notes
vlnII notes
kazoo

The only reason the head layout may matter is if you want to do the
process in reverse.  Parts will be written laid out in the same way as
the header by writesly.

A line which ends with a "%" will continue to the same field.  Empty
fields become blank lines in the target file, except for the comment
field.  Example:

!!
dummy4.ly !! tpt4.ly !! vlnII4.ly
kazoo4.ly
!!!! dummy notes !! tpt notes !!vlnII notes !! kazoo %
more kazoo  %
more kazoo  %
more kazoo 
!!  dummy notes !! tpt notes !!vlnII notes !! kazoo

Here are some embedded sly files.  If you have them in a lilypond
file and run sly on it, sly files will be written and processed.

%{::!! (the rest of the line is not used)
dummy3.ly !! tpt3.ly !! vlnII3.ly
kazoo3.ly
!!!! dummy notes !! tpt notes !!vlnII notes !! kazoo
!!  dummy notes !! tpt notes !!vlnII notes !! kazoo
%}

%{::!!
dummy4.ly !! tpt4.ly !! vlnII4.ly
kazoo4.ly
!!!! dummy notes !! tpt notes !!vlnII notes !! kazoo
!!  dummy notes !! tpt notes !!vlnII notes !! kazoo
%}

Here is another use for sly. It can make a single file, using
the comment field also to reduce typing:

%{::!!
file.sed
!!
s/this/that/g
s/here/there/g
%}

Begin an embedded sly file at the beginning of a line.  Anything
before or after it on the line will be discarded.

The screen output can help debug your file.  If you misplace a single
field separator you can get real scrambled.  Sly prints the contents
of the first non comment field to screen, so if you use a dummy make
it the first target file.  Before that first field with content there
is the comment field, the zeroth so to speak, which is usually best left
empty.

To see detailed help, use a pager: $ sly.py --help | more
or redirect the output to a file:  $ sly.py --help > file.txt
or scroll up with some shells and systems.   
  '''
  sys.exit(0)
                                                                   
def inputfile():
  '''Acqqire initial command line.  Return file name, species.'''
  arg = sys.argv[1:]
  if not arg:
    usage()
  else:
    arg = arg[0]
  if arg=="--help":
    helpPage()
  if not os.path.isfile(arg):
    print "Can't find file: " + arg
    sys.exit(0)
  if arg[-3:]=='.ly':
    species = 0
  elif arg[-4:]=='.sly':
    species = 1
  else:
    print "Don't know what to do with this file: " + arg
    sys.exit(0)
  return arg, species

def makesly(filename):
  ''' open lilypond file, create sly files,
      return list of sly files '''
  print "starting makesly"
  opensep = '%{::'
  closesep = '%}'
  filelist = []
  iter = 0
  file = ''
  for line in open(filename).readlines():
    iter = iter + 1
    if line.find(opensep)>-1:
      line = line.split(opensep)
      fsep = line[1][:2]
      if fsep.strip()!=fsep:
        print "Bad field separator on line", iter, "of", filename,
        print "so nothing was written."
        sys.exit(0)
      # filename is known to have '.ly' extension
      slyfilename = 'sly-' + filename[:-3] + str(iter) + ".sly"
      # rest of 1st embedded line not used: line[1][2:].strip()
      file = open(slyfilename,'w')
      timestr = ' ' + time.asctime(time.localtime(time.time())) + '\n'
      headline = fsep + ' ' + slyfilename + ' from ' + filename + timestr
      file.write(headline)
      print headline,
      filelist.append(slyfilename)
      continue
    if line.find(closesep)==-1:
      if file:
        file.write(line)
    if line.find(closesep)>-1:
      line = line.split(closesep)[0]
      if file:
        file.write(line)
        file = ''
  return filelist
 
def rip(file):
  '''file is name, not open'''
  print "\nRipping ", file, "::::::::::::::::::::::::::"
  file = open(file)
  comment = file.readline()
  fsep = comment[:2]
  if fsep.strip()!=fsep:
    # if lily file, won't get this far.
    print "Bad field separator at top of file",
    print "so nothing was written."
    sys.exit(0)
  # Put whole file in memory. 
  lines = []
  for line in file:
    line = line.strip()
    lines.append(line)
  lines = '\n'.join(lines)
  all = lines.split('\n' + fsep, 1)
  head, data = all[0], all[1]
  if len(data.split('\n'))<2 and len(data.split(fsep))<2:
    print "Bare header.  No lilypond files were written."
    sys.exit(0)
  
  # Process head, get names into list
  filelist = fsep.join(head.split('\n')) # sub fsep for newline
  filelist = filelist.split(fsep)
  names = []
  print "Writing files:"
  for filename in filelist:
    name = filename.strip()
    print '\t\t' + name
    target = open(name, 'w')
    names.append(target) # "names" is list of opened target files
    print "Data written to first file, with field numbers, except that comment"
    print "fields (which start at 0) were not written if they were empty." 
 
    # Process data...
  data = data.split('\n') # arrange data in lines
  data = fsep.join(data).rstrip() # rstrip & make newline new field
  data = data.split('%' + fsep) # split at lily comment if at end of field
  data = '%\n'.join(data) # join so now fields can have multiple lines
  data = data.split(fsep)
  count = 0 # start number of fields at one 1st comment gets mod zero 
  volte = len(names)+1 # constant: number of targets 
  for field in data:    
    opnum = 0 # index sts at 0, but 2nd iter=1st file.
    for target in names:      
      if (count % volte)==0: # write to all files
        if opnum==0:
          print count, field
        if field.strip()!='': # but only if comment exists.       
          target.write(field + '\n')                   
      if (count % volte)==opnum+1: # zero pass is comment        
        names[opnum].write(field + '\n')
        if opnum==0:
          print count, "field 1:", field
        else:
          print count,
      opnum = opnum + 1 # index next target file                   
    count = count + 1 # next field

import string, os, sys, time

try:
  infile, species = inputfile()
  if species==0:
    for file in makesly(infile):
      rip(file)
  if species==1:
    rip(infile)
  print '\n' + 'Sly is done.  Redirect the above if problems.  daveA'

except:
  sys.exit(0)
  #print "main-errors: ", sys.exc_type, sys.exc_value