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@node ax_normalize_path
@unnumberedsec ax_normalize_path
@majorheading Synopsis
@smallexample
AX_NORMALIZE_PATH(VARNAME, [REFERENCE_STRING])
@end smallexample
@majorheading Description
Perform some cleanups on the value of $VARNAME (interpreted as a path):
@smallexample
- empty paths are changed to '.'
- trailing slashes are removed
- repeated slashes are squeezed except a leading doubled slash '//'
(which might indicate a networked disk on some OS).
@end smallexample
REFERENCE_STRING is used to turn '/' into '\' and vice-versa: if
REFERENCE_STRING contains some backslashes, all slashes and backslashes
are turned into backslashes, otherwise they are all turned into slashes.
This makes processing of DOS filenames quite easier, because you can
turn a filename to the Unix notation, make your processing, and turn it
back to original notation.
@smallexample
filename='A:\FOO\\BAR\'
old_filename="$filename"
# Switch to the unix notation
AX_NORMALIZE_PATH([filename], ["/"])
# now we have $filename = 'A:/FOO/BAR' and we can process it as if
# it was a Unix path. For instance let's say that you want
# to append '/subpath':
filename="$filename/subpath"
# finally switch back to the original notation
AX_NORMALIZE_PATH([filename], ["$old_filename"])
# now $filename equals to 'A:\FOO\BAR\subpath'
@end smallexample
One good reason to make all path processing with the unix convention is
that backslashes have a special meaning in many cases. For instance
@smallexample
expr 'A:\FOO' : 'A:\Foo'
@end smallexample
will return 0 because the second argument is a regex in which
backslashes have to be backslashed. In other words, to have the two
strings to match you should write this instead:
@smallexample
expr 'A:\Foo' : 'A:\\Foo'
@end smallexample
Such behavior makes DOS filenames extremely unpleasant to work with. So
temporary turn your paths to the Unix notation, and revert them to the
original notation after the processing. See the macro
AX_COMPUTE_RELATIVE_PATHS for a concrete example of this.
REFERENCE_STRING defaults to $VARIABLE, this means that slashes will be
converted to backslashes if $VARIABLE already contains some backslashes
(see $thirddir below).
@smallexample
firstdir='/usr/local//share'
seconddir='C:\Program Files\\'
thirddir='C:\home/usr/'
AX_NORMALIZE_PATH([firstdir])
AX_NORMALIZE_PATH([seconddir])
AX_NORMALIZE_PATH([thirddir])
# $firstdir = '/usr/local/share'
# $seconddir = 'C:\Program Files'
# $thirddir = 'C:\home\usr'
@end smallexample
@majorheading Source Code
Download the
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_normalize_path.m4,latest
version of @file{ax_normalize_path.m4}} or browse
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=history;f=m4/ax_normalize_path.m4,the
macro's revision history}.
@majorheading License
@w{Copyright @copyright{} 2008 Alexandre Duret-Lutz @email{adl@@gnu.org}}
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see <http://www.gnu.org/licenses/>.
As a special exception, the respective Autoconf Macro's copyright owner
gives unlimited permission to copy, distribute and modify the configure
scripts that are the output of Autoconf when processing the Macro. You
need not follow the terms of the GNU General Public License when using
or distributing such scripts, even though portions of the text of the
Macro appear in them. The GNU General Public License (GPL) does govern
all other use of the material that constitutes the Autoconf Macro.
This special exception to the GPL applies to versions of the Autoconf
Macro released by the Autoconf Archive. When you make and distribute a
modified version of the Autoconf Macro, you may extend this special
exception to the GPL to apply to your modified version as well.
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