(Random): Add *random-state* variable, put note at

[bpt/guile.git] / doc / ref / scheme-data.texi

diff --git a/doc/ref/scheme-data.texi b/doc/ref/scheme-data.texi
index f451707..a05a07e 100755 (executable)
--- a/doc/ref/scheme-data.texi
+++ b/doc/ref/scheme-data.texi
@@ -1229,6 +1229,11 @@ through @var{end} (exclusive) bits of @var{n}.  The
 @node Random
 @subsection Random Number Generation
 
+Pseudo-random numbers are generated from a random state object, which
+can be created with @code{seed->random-state}.  The @var{state}
+parameter to the various functions below is optional, it defaults to
+the state object in the @code{*random-state*} variable.
+
 @deffn {Scheme Procedure} copy-random-state [state]
 @deffnx {C Function} scm_copy_random_state (state)
 Return a copy of the random state @var{state}.
@@ -1242,12 +1247,6 @@ Accepts a positive integer or real n and returns a
 number of the same type between zero (inclusive) and
 @var{n} (exclusive). The values returned have a uniform
 distribution.
-
-The optional argument @var{state} must be of the type produced
-by @code{seed->random-state}. It defaults to the value of the
-variable @code{*random-state*}. This object is used to maintain
-the state of the pseudo-random-number generator and is altered
-as a side effect of the random operation.
 @end deffn
 
 @deffn {Scheme Procedure} random:exp [state]
@@ -1302,6 +1301,11 @@ Return a uniformly distributed inexact real random number in
 Return a new random state using @var{seed}.
 @end deffn
 
+@defvar *random-state*
+The global random state used by the above functions when the
+@var{state} parameter is not given.
+@end defvar
+
 
 @node Characters
 @section Characters