From 8466d8cfa486fb30d1755c4261b781135083787b Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Mon, 20 Feb 2017 00:05:29 -0800
Subject: Import Upstream version 3a1

---
 alist.scm | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 53 insertions(+), 2 deletions(-)

(limited to 'alist.scm')

diff --git a/alist.scm b/alist.scm
index 5917c7c..f1bdd70 100644
--- a/alist.scm
+++ b/alist.scm
@@ -1,5 +1,5 @@
 ;;;"alist.scm", alist functions for Scheme.
-;;;Copyright (c) 1992, 1993 Aubrey Jaffer
+;;;Copyright (c) 1992, 1993, 2003 Aubrey Jaffer
 ;
 ;Permission to copy this software, to modify it, to redistribute it,
 ;to distribute modified versions, and to use it for any purpose is
@@ -8,7 +8,7 @@
 ;1.  Any copy made of this software must include this copyright notice
 ;in full.
 ;
-;2.  I have made no warrantee or representation that the operation of
+;2.  I have made no warranty or representation that the operation of
 ;this software will be error-free, and I am under no obligation to
 ;provide any services, by way of maintenance, update, or otherwise.
 ;
@@ -17,6 +17,23 @@
 ;promotional, or sales literature without prior written consent in
 ;each case.
 
+;;@code{(require 'alist)}
+;;@ftindex alist
+;;
+;;Alist functions provide utilities for treating a list of key-value pairs
+;;as an associative database.  These functions take an equality predicate,
+;;@var{pred}, as an argument.  This predicate should be repeatable,
+;;symmetric, and transitive.
+;;
+;;Alist functions can be used with a secondary index method such as hash
+;;tables for improved performance.
+
+;;@body
+;;Returns an @dfn{association function} (like @code{assq}, @code{assv}, or
+;;@code{assoc}) corresponding to @var{pred}.  The returned function
+;;returns a key-value pair whose key is @code{pred}-equal to its first
+;;argument or @code{#f} if no key in the alist is @var{pred}-equal to the
+;;first argument.
 (define (predicate->asso pred)
   (cond ((eq? eq? pred) assq)
 	((eq? = pred) assv)
@@ -30,12 +47,28 @@
 			((pred key (caar al)) (car al))
 			(else (l (cdr al)))))))))
 
+;;@body
+;;Returns a procedure of 2 arguments, @var{alist} and @var{key}, which
+;;returns the value associated with @var{key} in @var{alist} or @code{#f} if
+;;@var{key} does not appear in @var{alist}.
 (define (alist-inquirer pred)
   (let ((assofun (predicate->asso pred)))
     (lambda (alist key)
       (let ((pair (assofun key alist)))
 	(and pair (cdr pair))))))
 
+;;@body
+;;Returns a procedure of 3 arguments, @var{alist}, @var{key}, and
+;;@var{value}, which returns an alist with @var{key} and @var{value}
+;;associated.  Any previous value associated with @var{key} will be
+;;lost.  This returned procedure may or may not have side effects on its
+;;@var{alist} argument.  An example of correct usage is:
+;;
+;;@lisp
+;;(define put (alist-associator string-ci=?))
+;;(define alist '())
+;;(set! alist (put alist "Foo" 9))
+;;@end lisp
 (define (alist-associator pred)
   (let ((assofun (predicate->asso pred)))
     (lambda (alist key val)
@@ -44,6 +77,16 @@
 		    alist)
 	      (else (cons (cons key val) alist)))))))
 
+;;@body
+;;Returns a procedure of 2 arguments, @var{alist} and @var{key}, which
+;;returns an alist with an association whose @var{key} is key removed.
+;;This returned procedure may or may not have side effects on its
+;;@var{alist} argument.  An example of correct usage is:
+;;
+;;@lisp
+;;(define rem (alist-remover string-ci=?))
+;;(set! alist (rem alist "foo"))
+;;@end lisp
 (define (alist-remover pred)
   (lambda (alist key)
     (cond ((null? alist) alist)
@@ -58,9 +101,17 @@
 		    (set-cdr! al (cddr al)) alist)
 		   (else (l (cdr al)))))))))
 
+;;@body
+;;Returns a new association list formed by mapping @var{proc} over the
+;;keys and values of @var{alist}.   @var{proc} must be a function of 2
+;;arguments which returns the new value part.
 (define (alist-map proc alist)
   (map (lambda (pair) (cons (car pair) (proc (car pair) (cdr pair))))
        alist))
 
+;;@body
+;;Applies @var{proc} to each pair of keys and values of @var{alist}.
+;;@var{proc} must be a function of 2 arguments.  The returned value is
+;;unspecified.
 (define (alist-for-each proc alist)
   (for-each (lambda (pair) (proc (car pair) (cdr pair))) alist))
-- 
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