diff options
Diffstat (limited to 'alist.txi')
-rw-r--r-- | alist.txi | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/alist.txi b/alist.txi new file mode 100644 index 0000000..804df8a --- /dev/null +++ b/alist.txi @@ -0,0 +1,70 @@ +@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. + + +@defun predicate->asso pred + +Returns an @dfn{association function} (like @code{assq}, @code{assv}, or +@cindex association function +@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. +@end defun + +@defun alist-inquirer pred + +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}. +@end defun + +@defun alist-associator pred + +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 +@end defun + +@defun alist-remover pred + +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 +@end defun + +@defun alist-map proc alist + +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. +@end defun + +@defun alist-for-each proc alist + +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. +@end defun |