Finished up function call support.

1 files changed, 27 insertions, 0 deletions

diff --git a/common/dhcp-eval.5 b/common/dhcp-eval.5
index 7d33bd67..59cfc75b 100644
--- a/common/dhcp-eval.5
+++ b/common/dhcp-eval.5
@@ -350,6 +350,33 @@ the current time and the time that the lease expires.
 Any number between zero and the maximum representable size may be
 specified as a numeric expression.
 .RE
+.SH
+FUNCTIONS
+Functions may be defined with the \fBdefine\fR statement.  A function
+definition may occur anywhere that regular statement may appear.
+Functions occupy the same namespace as variables, and obey the same
+scoping rules.
+.PP
+.nf
+define set-hostname(prefix) {
+  option host-name
+    concat (prefix, binary-to-ascii (16, 32, "", leased-address));
+}
+.fi
+.PP
+A function may return a value when used in an expression with the
+\fBreturn\fR statement.  A function with no return statement has a
+value of null.
+.PP
+.nf
+define make-hostname(prefix) {
+  return concat (prefix, binary-to-ascii (16, 32, "", leased-address));
+}
+
+option host-name make-hostname("dyn-");
+.fi
+.PP
+.RE
 .SH REFERENCE: LOGGING
 Logging statements may be used to send information to the standard logging
 channels.  A logging statement includes an optional priority (\fBfatal\fR,