[PATCH] doc: describe the -e (module) shorthand as on equal footing with (@ ...)

[arne_bab@web.de]

 doc/ref/guile-invoke.texi   |  15 ++++------
 doc/ref/scheme-scripts.texi |  62 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 9 deletions(-)


# HG changeset patch
# User Arne Babenhauserheide <arne.babenhauserheide@kit.edu>
# Date 1463602731 -7200
#      Wed May 18 22:18:51 2016 +0200
# Node ID e5938da9b89fcee1936487df32fb649135d8a94c
# Parent  4f269918e38cd48905546c485173c4f9dbfa0717
doc: describe the -e (module) shorthand as on equal footing with (@ ...)

diff --git a/doc/ref/guile-invoke.texi b/doc/ref/guile-invoke.texi
--- a/doc/ref/guile-invoke.texi
+++ b/doc/ref/guile-invoke.texi
@@ -102,15 +102,12 @@ that is defined in the script.  It can a
 @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
-Examples}.
+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 @code{(@@ @var{module-name}  main)} with @code{(symbol ...)}
+the @var{module-name}.  To use a different function than @var{main},
+you can use the form @code{(symbol ...)  function}.  See @ref{Using
+Guile Modules} and @ref{Scripting Examples}.
 
 @item -ds
 Treat a final @option{-s} option as if it occurred at this point in the
diff --git a/doc/ref/scheme-scripts.texi b/doc/ref/scheme-scripts.texi
--- 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")}.
 
+@item guile -e '(ex4)' -s /u/jimb/ex4.scm foo
+Load the file @file{/u/jimb/ex4.scm}, and then call the function
+@code{main} from the module '(ex4)', passing it the list
+@code{("/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}
@@ -402,6 +407,63 @@ 1
 100891344545564193334812497256
 @end example
 
+To execute the function main from a module, we can use the special form
+@code{(@@ (module) function)}:
+@example
+#!/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)))
+@end example
+
+We can use @code{@@@@} to run non-exported functions. For exported
+functions, we can simplify this call with the shorthand @code{(module)}:
+@example
+#!/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)))
+@end example
+
+For maximum portability among *nixes, we can use the shell to
+@code{exec} guile with specified command line arguments. Here we need to
+take care to quote the command arguments correctly:
+@example
+#!/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)))
+@end example
 
 @c Local Variables:
 @c TeX-master: "guile.texi"