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authorLudovic Courtès <ludo@gnu.org>2023-08-14 15:08:00 +0200
committerLudovic Courtès <ludo@gnu.org>2023-08-15 00:33:50 +0200
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doc: cookbook: Mention common SRFI-1 procedures.
* doc/guix-cookbook.texi (A Scheme Crash Course): Add item about SRFI-1.
Diffstat (limited to 'doc/guix-cookbook.texi')
-rw-r--r--doc/guix-cookbook.texi30
1 files changed, 29 insertions, 1 deletions
diff --git a/doc/guix-cookbook.texi b/doc/guix-cookbook.texi
index 28303df37b..ee66dad7d9 100644
--- a/doc/guix-cookbook.texi
+++ b/doc/guix-cookbook.texi
@@ -192,7 +192,8 @@ rest are the arguments passed to the function. Every function returns the
last evaluated expression as its return value.
@item
-Anonymous functions are declared with the @code{lambda} term:
+Anonymous functions---@dfn{procedures} in Scheme parlance---are declared
+with the @code{lambda} term:
@lisp
(lambda (x) (* x x))
@@ -208,6 +209,9 @@ which can in turn be applied to an argument:
@result{} 9
@end lisp
+Procedures are regular values just like numbers, strings, Booleans, and
+so on.
+
@item
Anything can be assigned a global name with @code{define}:
@@ -234,6 +238,30 @@ A list structure can be created with the @code{list} procedure:
@end lisp
@item
+Standard procedures are provided by the @code{(srfi srfi-1)} module to
+create and process lists (@pxref{SRFI-1, list processing,, guile, GNU
+Guile Reference Manual}). Here are some of the most useful ones in
+action:
+
+@lisp
+(use-modules (srfi srfi-1)) ;import list processing procedures
+
+(append (list 1 2) (list 3 4))
+@result{} (1 2 3 4)
+
+(map (lambda (x) (* x x)) (list 1 2 3 4))
+@result{} (1 4 9 16)
+
+(delete 3 (list 1 2 3 4)) @result{} (1 2 4)
+(filter odd? (list 1 2 3 4)) @result{} (1 3)
+(remove even? (list 1 2 3 4)) @result{} (1 3)
+(find number? (list "a" 42 "b")) @result{} 42
+@end lisp
+
+Notice how the first argument to @code{map}, @code{filter},
+@code{remove}, and @code{find} is a procedure!
+
+@item
@cindex S-expression
The @dfn{quote} disables evaluation of a parenthesized expression, also
called an S-expression or ``s-exp'': the first term is not called over