Warning: This is the manual of the legacy Guile 2.0 series. You may want to read the manual of the current stable series instead.
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The procedure in the previous section look for Scheme code in the file system at specific location. Guile also has some procedures to search the load path for code.
List of directories which should be searched for Scheme modules and
libraries. When Guile starts up, %load-path
is initialized to
the default load path (list (%library-dir) (%site-dir)
(%global-site-dir) (%package-data-dir))
. The GUILE_LOAD_PATH
environment variable can be used to prepend or append additional
directories (see Environment Variables).
See Build Config, for more on %site-dir
and related
procedures.
Similar to load
, but searches for filename in the load
paths. Preferentially loads a compiled version of the file, if it is
available and up-to-date.
A user can extend the load path by calling add-to-load-path
.
Add dir to the load path.
For example, a script might include this form to add the directory that it is in to the load path:
(add-to-load-path (dirname (current-filename)))
It’s better to use add-to-load-path
than to modify
%load-path
directly, because add-to-load-path
takes care
of modifying the path both at compile-time and at run-time.
Search %load-path
for the file named filename and
load it into the top-level environment. If filename is a
relative pathname and is not found in the list of search paths,
an error is signalled. Preferentially loads a compiled version of the
file, if it is available and up-to-date.
If filename is a relative pathname and is not found in the list of
search paths, one of three things may happen, depending on the optional
second argument, exception-on-not-found. If it is #f
,
#f
will be returned. If it is a procedure, it will be called
with no arguments. (This allows a distinction to be made between
exceptions raised by loading a file, and exceptions related to the
loader itself.) Otherwise an error is signalled.
For compatibility with Guile 1.8 and earlier, the C function takes only one argument, which can be either a string (the file name) or an argument list.
Search %load-path
for the file named filename, which must
be readable by the current user. If filename is found in the list
of paths to search or is an absolute pathname, return its full pathname.
Otherwise, return #f
. Filenames may have any of the optional
extensions in the %load-extensions
list; %search-load-path
will try each extension automatically.
A list of default file extensions for files containing Scheme code.
%search-load-path
tries each of these extensions when looking for
a file to load. By default, %load-extensions
is bound to the
list ("" ".scm")
.
As mentioned above, when Guile searches the %load-path
for a
source file, it will also search the %load-compiled-path
for a
corresponding compiled file. If the compiled file is as new or newer
than the source file, it will be loaded instead of the source file,
using load-compiled
.
Like %load-path
, but for compiled files. By default, this path
has two entries: one for compiled files from Guile itself, and one for
site packages. The GUILE_LOAD_COMPILED_PATH
environment variable
can be used to prepend or append additional directories
(see Environment Variables).
When primitive-load-path
searches the %load-compiled-path
for a corresponding compiled file for a relative path it does so by
appending .go
to the relative path. For example, searching for
ice-9/popen
could find
/usr/lib/guile/2.0/ccache/ice-9/popen.go
, and use it instead of
/usr/share/guile/2.0/ice-9/popen.scm
.
If primitive-load-path
does not find a corresponding .go
file in the %load-compiled-path
, or the .go
file is out of
date, it will search for a corresponding auto-compiled file in the
fallback path, possibly creating one if one does not exist.
See Installing Site Packages, for more on how to correctly install site packages. See Modules and the File System, for more on the relationship between load paths and modules. See Compilation, for more on the fallback path and auto-compilation.
Finally, there are a couple of helper procedures for general path manipulation.
Parse path, which is expected to be a colon-separated string, into
a list and return the resulting list with tail appended. If
path is #f
, tail is returned.
Parse path, which is expected to be a colon-separated string, into
a list and return the resulting list with base (a list) spliced in
place of the ...
path component, if present, or else base
is added to the end. If path is #f
, base is
returned.
Search path for a directory containing a file named
filename. The file must be readable, and not a directory. If we
find one, return its full filename; otherwise, return #f
. If
filename is absolute, return it unchanged. If given,
extensions is a list of strings; for each directory in path,
we search for filename concatenated with each extension. If
require-exts? is true, require that the returned file name have
one of the given extensions; if require-exts? is not given, it
defaults to #f
.
For compatibility with Guile 1.8 and earlier, the C function takes only three arguments.
Next: Character Encoding of Source Files, Previous: Loading, Up: Read/Load/Eval/Compile [Contents][Index]