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Please document include and include-from-path |
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Date: |
Mon, 19 Dec 2011 15:12:22 +0000 |
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Mozilla/5.0 (X11; Linux i686; rv:8.0) Gecko/20111124 Thunderbird/8.0 |
I think I know what these do, but could you include them in the docs,
and point out how differ from load and load-from-path.
Documentation something like this?
— Scheme Procedure: include filename
Load filename and add its contents to a file currently being
compiled. Unlike /load/ its contents are not evaluated immediately.
The load paths are not searched.
— Scheme Procedure: include-from-path filename
Locate /filename/ in the load paths, load /filename/ and add its
contents to a file currently being compiled. Unlike
/load-from-path/ its contents are not evaluated immediately.
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Subject: |
Re: bug#10327: Please document include and include-from-path |
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Date: |
Fri, 27 Jan 2012 16:31:31 +0100 |
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Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) |
Hello Ian & Ian :)
Thanks for the report. I added some extensive docs.
6.17.11 Local Inclusion
-----------------------
This section has discussed various means of linking Scheme code
together: fundamentally, loading up files at run-time using `load' and
`load-compiled'. Guile provides another option to compose parts of
programs together at expansion-time instead of at run-time.
-- Scheme Syntax: include file-name
Open FILE-NAME, at expansion-time, and read the Scheme forms that
it contains, splicing them into the location of the `include',
within a `begin'.
If you are a C programmer, if `load' in Scheme is like `dlopen' in
C, consider `include' to be like the C preprocessor's `#include'. When
you use `include', it is as if the contents of the included file were
typed in instead of the `include' form.
Because the code is included at compile-time, it is available to the
macroexpander. Syntax definitions in the included file are available to
later code in the form in which the `include' appears, without the need
for `eval-when'. (*Note Eval When::.)
For the same reason, compiling a form that uses `include' results in
one compilation unit, composed of multiple files. Loading the compiled
file is one `stat' operation for the compilation unit, instead of `2*N'
in the case of `load' (once for each loaded source file, and once each
corresponding compiled file, in the best case).
Unlike `load', `include' also works within nested lexical contexts.
It so happens that the optimizer works best within a lexical context,
because all of the uses of bindings in a lexical context are visible,
so composing files by including them within a `(let () ...)' can
sometimes lead to important speed improvements.
On the other hand, `include' does have all the disadvantages of
early binding: once the code with the `include' is compiled, no change
to the included file is reflected in the future behavior of the
including form.
Also, the particular form of `include', which requires an absolute
path, or a path relative to the current directory at compile-time, is
not very amenable to compiling the source in one place, but then
installing the source to another place. For this reason, Guile provides
another form, `include-from-path', which looks for the source file to
include within a load path.
-- Scheme Syntax: include-from-path file-name
Like `include', but instead of expecting `file-name' to be an
absolute file name, it is expected to be a relative path to search
in the `%load-path'.
`include-from-path' is more useful when you want to install all of
the source files for a package (as you should!). It makes it possible
to evaluate an installed file from source, instead of relying on the
`.go' file being up to date.
On Sat 24 Dec 2011 00:53, Ian Price <address@hidden> writes:
> Or am I being ever so slightly patronising?
"Recursion and condescension"? :-)
http://james-iry.blogspot.com/2009/05/brief-incomplete-and-mostly-wrong.html
Cheers,
Andy
--
http://wingolog.org/
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