From 60a9fcb1377e4acc78a930904ef80b69a1c63f25 Mon Sep 17 00:00:00 2001 From: Chris Marusich Date: Thu, 6 Apr 2017 02:28:35 -0700 Subject: monads, doc: Improve mwhen and munless documentation. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * doc/guix.texi (The Store Monad) : Document them. * guix/monads.scm (mwhen, munless): Clarify their intended use. Signed-off-by: Ludovic Courtès --- doc/guix.texi | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'doc') diff --git a/doc/guix.texi b/doc/guix.texi index d0f21edeec..62f4483b85 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -4054,6 +4054,20 @@ monadic expressions are ignored. In that sense, it is analogous to @code{begin}, but applied to monadic expressions. @end deffn +@deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ... +When @var{condition} is true, evaluate the sequence of monadic +expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When +@var{condition} is false, return @code{*unspecified*} in the current +monad. Every expression in the sequence must be a monadic expression. +@end deffn + +@deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ... +When @var{condition} is false, evaluate the sequence of monadic +expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When +@var{condition} is true, return @code{*unspecified*} in the current +monad. Every expression in the sequence must be a monadic expression. +@end deffn + @cindex state monad The @code{(guix monads)} module provides the @dfn{state monad}, which allows an additional value---the state---to be @emph{threaded} through -- cgit v1.2.3