[Guile-commits] 02/04: doc: Describe -e (module) on equal footing with (@ ...).

[Ludovic Courtès]

civodul pushed a commit to branch stable-2.0
in repository guile.

commit 8a5e40655b59f9f6e3913a95461b3f6970497f3b
Author: Arne Babenhauserheide <address@hidden>
Date:   Thu Sep 29 17:11:26 2016 +0200

    doc: Describe -e (module) on equal footing with (@ ...).
    
    * doc/ref/guile-invoke.texi, doc/ref/scheme-scripts.texi:
    describe the -e (module) shorthand as on equal footing with (@ ...)
    
    Co-authored-by: Ludovic Courtès <address@hidden>
---
 doc/ref/guile-invoke.texi   | 12 +++-----
 doc/ref/scheme-scripts.texi | 67 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 8 deletions(-)

diff --git a/doc/ref/guile-invoke.texi b/doc/ref/guile-invoke.texi
index 5be8f20..54c8f9b 100644
--- a/doc/ref/guile-invoke.texi
+++ b/doc/ref/guile-invoke.texi
@@ -102,14 +102,10 @@ that is defined in the script.  It can also be of the 
form @code{(@@
 @var{module-name} @var{symbol})}, and in that case, the symbol is
 looked up in the module named @var{module-name}.
 
-For compatibility with some versions of Guile 1.4, you can also use the
-form @code{(symbol ...)} (that is, a list of only symbols that doesn't
-start with @code{@@}), which is equivalent to @code{(@@ (symbol ...)
-main)}, or @code{(symbol ...)  symbol} (that is, a list of only symbols
-followed by a symbol), which is equivalent to @code{(@@ (symbol ...)
-symbol)}.  We recommend to use the equivalent forms directly since they
-correspond to the @code{(@@ ...)}  read syntax that can be used in
-normal code.  See @ref{Using Guile Modules} and @ref{Scripting
+As a shorthand you can use the form @code{(symbol ...)}, that is, a list
+of only symbols that doesn't start with @code{@@}.  It is equivalent to
address@hidden(@@ @var{module-name} main)}, where @var{module-name} is
address@hidden(symbol ...)} form.  @xref{Using Guile Modules} and @ref{Scripting
 Examples}.
 
 @item -ds
diff --git a/doc/ref/scheme-scripts.texi b/doc/ref/scheme-scripts.texi
index 7552dba..3aedf05 100644
--- a/doc/ref/scheme-scripts.texi
+++ b/doc/ref/scheme-scripts.texi
@@ -293,6 +293,11 @@ and exit.
 Load the file @file{/u/jimb/ex4}, and then call the function
 @code{main}, passing it the list @code{("/u/jimb/ex4" "foo")}.
 
address@hidden guile -e '(ex4)' -s /u/jimb/ex4.scm foo
+Load the file @file{/u/jimb/ex4.scm}, and then call the function
address@hidden from the module '(ex4)', passing it the list
address@hidden("/u/jimb/ex4" "foo")}.
+
 @item guile -l first -ds -l last -s script
 Load the files @file{first}, @file{script}, and @file{last}, in that
 order.  The @code{-ds} switch says when to process the @code{-s}
@@ -369,6 +374,7 @@ Suppose that we now want to write a script which computes 
the
 @code{(choose @var{n} @var{m})} is the number of distinct subsets
 containing @var{n} objects each.  It's easy to write @code{choose} given
 @code{fact}, so we might write the script this way:
+
 @example
 #!/usr/local/bin/guile \
 -l fact -e main -s
@@ -402,6 +408,67 @@ $ ./choose 50 100
 100891344545564193334812497256
 @end example
 
+To call a specific procedure from a given module, we can use the special
+form @code{(@@ (@var{module}) @var{procedure})}:
+
address@hidden
+#!/usr/local/bin/guile \
+-l fact -e (@@ (fac) main) -s
+!#
+(define-module (fac)
+  #:export (main))
+
+(define (choose n m)
+  (/ (fact m) (* (fact (- m n)) (fact n))))
+
+(define (main args)
+  (let ((n (string->number (cadr args)))
+        (m (string->number (caddr args))))
+    (display (choose n m))
+    (newline)))
address@hidden example
+
+We can use @code{@@@@} to invoke non-exported procedures.  For exported
+procedures, we can simplify this call with the shorthand
address@hidden(@var{module})}:
+
address@hidden
+#!/usr/local/bin/guile \
+-l fact -e (fac) -s
+!#
+(define-module (fac)
+  #:export (main))
+
+(define (choose n m)
+  (/ (fact m) (* (fact (- m n)) (fact n))))
+
+(define (main args)
+  (let ((n (string->number (cadr args)))
+        (m (string->number (caddr args))))
+    (display (choose n m))
+    (newline)))
address@hidden example
+
+For maximum portability, we can instead use the shell to execute
address@hidden with specified command line arguments.  Here we need to
+take care to quote the command arguments correctly:
+
address@hidden
+#!/usr/bin/env sh
+exec guile -l fact -e '(@@ (fac) main)' -s "$0" "$@"
+!#
+(define-module (fac)
+  #:export (main))
+
+(define (choose n m)
+  (/ (fact m) (* (fact (- m n)) (fact n))))
+
+(define (main args)
+  (let ((n (string->number (cadr args)))
+        (m (string->number (caddr args))))
+    (display (choose n m))
+    (newline)))
address@hidden example
 
 @c Local Variables:
 @c TeX-master: "guile.texi"