From: Tim Vaughan <tgvaughan@gmail.com>
Date: Tue, 26 Apr 2016 19:38:43 +0000 (+1200)
Subject: Working on ROLL, redefined SPACES
X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?p=forth.jl.git;a=commitdiff_plain;h=efcae7affe8a5106424a7f0b67a1fd550e8cb320

Working on ROLL, redefined SPACES
---

diff --git a/src/lib.4th b/src/lib.4th
index 51f0b97..1f97d20 100644
--- a/src/lib.4th
+++ b/src/lib.4th
@@ -170,16 +170,15 @@
         @               ( and fetch )
 ;
 
+: ROLL ( x_u x_u-1... x_0 u -- x_u-1 ... x_0 x_u )
+        1+ DUP PICK SWAP    ( x_u x_u-1 ... x_0 x_u u+1 )
+;
 
 ( With the looping constructs, we can now write SPACES, which writes n spaces to stdout. )
 : SPACES        ( n -- )
-        BEGIN
-                DUP 0>          ( while n > 0 )
-        WHILE
-                SPACE           ( print a space )
-                1-              ( until we count down to 0 )
-        REPEAT
-        DROP
+        0 DO
+            SPACE
+        LOOP
 ;
 
 ( Standard words for manipulating BASE. )