py_compile Namespace Reference

Functions
def	wr_long
def	compile

Variables
tuple	MAGIC = imp.get_magic()
list	__all__ = ["compile"]

Detailed Description

Routine to "compile" a .py file to a .pyc (or .pyo) file.

This module has intimate knowledge of the format of .pyc files.

Function Documentation

def py_compile.compile	(		file,
			cfile = None,
			dfile = None
	)

Byte-compile one Python source file to Python bytecode.

Arguments:

file:  source filename
cfile: target filename; defaults to source with 'c' or 'o' appended
       ('c' normally, 'o' in optimizing mode, giving .pyc or .pyo)
dfile: purported filename; defaults to source (this is the filename
       that will show up in error messages)

Note that it isn't necessary to byte-compile Python modules for
execution efficiency -- Python itself byte-compiles a module when
it is loaded, and if it can, writes out the bytecode to the
corresponding .pyc (or .pyo) file.

However, if a Python installation is shared between users, it is a
good idea to byte-compile all modules upon installation, since
other users may not be able to write in the source directories,
and thus they won't be able to write the .pyc/.pyo file, and then
they would be byte-compiling every module each time it is loaded.
This can slow down program start-up considerably.

See compileall.py for a script/module that uses this module to
byte-compile all installed files (or all files in selected
directories).

Definition at line 18 of file py_compile.py.

References traceback.format_exception_only(), aifc.open(), and wr_long().

def compile(file, cfile=None, dfile=None):
    """Byte-compile one Python source file to Python bytecode.

    Arguments:

    file:  source filename
    cfile: target filename; defaults to source with 'c' or 'o' appended
           ('c' normally, 'o' in optimizing mode, giving .pyc or .pyo)
    dfile: purported filename; defaults to source (this is the filename
           that will show up in error messages)

    Note that it isn't necessary to byte-compile Python modules for
    execution efficiency -- Python itself byte-compiles a module when
    it is loaded, and if it can, writes out the bytecode to the
    corresponding .pyc (or .pyo) file.

    However, if a Python installation is shared between users, it is a
    good idea to byte-compile all modules upon installation, since
    other users may not be able to write in the source directories,
    and thus they won't be able to write the .pyc/.pyo file, and then
    they would be byte-compiling every module each time it is loaded.
    This can slow down program start-up considerably.

    See compileall.py for a script/module that uses this module to
    byte-compile all installed files (or all files in selected
    directories).

    """
    import os, marshal, __builtin__
    f = open(file)
    try:
        timestamp = long(os.fstat(f.fileno())[8])
    except AttributeError:
        timestamp = long(os.stat(file)[8])
    codestring = f.read()
    # If parsing from a string, line breaks are \n (see parsetok.c:tok_nextc)
    # Replace will return original string if pattern is not found, so
    # we don't need to check whether it is found first.
    codestring = codestring.replace("\r\n","\n")
    codestring = codestring.replace("\r","\n")
    f.close()
    if codestring and codestring[-1] != '\n':
        codestring = codestring + '\n'
    try:
        codeobject = __builtin__.compile(codestring, dfile or file, 'exec')
    except SyntaxError, detail:
        import traceback, sys
        lines = traceback.format_exception_only(SyntaxError, detail)
        for line in lines:
            sys.stderr.write(line.replace('File "<string>"',
                                            'File "%s"' % (dfile or file)))
        return
    if not cfile:
        cfile = file + (__debug__ and 'c' or 'o')
    fc = open(cfile, 'wb')
    fc.write('\0\0\0\0')
    wr_long(fc, timestamp)
    marshal.dump(codeobject, fc)
    fc.flush()
    fc.seek(0, 0)
    fc.write(MAGIC)
    fc.close()
    if os.name == 'mac':
        import macfs
        macfs.FSSpec(cfile).SetCreatorType('Pyth', 'PYC ')

def py_compile.wr_long	(		f,
			x
	)

Internal; write a 32-bit int to a file in little-endian order.

Definition at line 11 of file py_compile.py.

def wr_long(f, x):
    """Internal; write a 32-bit int to a file in little-endian order."""
    f.write(chr( x        & 0xff))
    f.write(chr((x >> 8)  & 0xff))
    f.write(chr((x >> 16) & 0xff))
    f.write(chr((x >> 24) & 0xff))