X-Git-Url: https://git.rrq.au/?a=blobdiff_plain;f=sys.f;h=6e7c8539bcdd67ea720b7faf5c2f15c8781b0880;hb=61b721d365efaaae4d5ebb8d13972faa697be54b;hp=604d87aa75e71f116f1177d048e18c4028a5b4b6;hpb=f05a9a424e2d5cfc15f55cee82f503d7b4c1e5a9;p=rrq%2Fjonasforth.git

diff --git a/sys.f b/sys.f
index 604d87a..6e7c853 100644
--- a/sys.f
+++ b/sys.f
@@ -10,10 +10,6 @@ EXIT [
   EXIT
 [ IMMEDIATE
 
-: / /MOD DROP ;
-: MOD /MOD SWAP DROP ;
-: NEG 0 SWAP - ;
-
 : IF IMMEDIATE
   ' 0BRANCH ,
   HERE @
@@ -37,48 +33,77 @@ EXIT [
   HERE @
 ;
 
+: AGAIN IMMEDIATE
+  ' BRANCH ,
+  HERE @ - , ;
+
+: ( IMMEDIATE
+  BEGIN
+    READ-WORD
+    1 = IF
+      C@ 41 = IF
+        EXIT
+      THEN
+    ELSE
+      DROP
+    THEN
+  AGAIN ; ( Yay! We now have comments! )
+
 : UNTIL IMMEDIATE
   ' 0BRANCH ,
   HERE @ - ,
 ;
 
-: FIB
-  0 1
-  0
-  BEGIN
-    ROT
-    DUP ROT +
-    ROT ROT
+( Compile a literal value into the current word. )
+: LIT, IMMEDIATE ( x -- )
+  ' LIT , , ;
 
-    1 +
-  DUP 4 PICK = UNTIL
-  DROP SWAP DROP SWAP DROP
-;
+: / /MOD DROP ;
+: MOD /MOD SWAP DROP ;
+: NEG 0 SWAP - ;
 
 : C,
   HERE @ C!
   HERE @ 1 +
   HERE ! ;
 
-: OVER
-  SWAP DUP ROT ;
+: OVER ( a b -- a b a ) SWAP DUP ROT ;
 
-: STORE-STRING
+( An alternative comment syntax. Reads until the end of the line. )
+: \ IMMEDIATE
+  BEGIN
+    KEY
+  10 = UNTIL ;
+
+\ So far, S" has only worked in immediate mode, which is backwards -- actually,
+\ the main use-case of this is as a compile-time word. Let's fix that.
+: S" IMMEDIATE
+  ' LITSTRING ,
+  HERE @ 0 C, \ We will put the length here
+  0
+  BEGIN
+    1 +
+    KEY DUP C,
+  34 = UNTIL
+  \ Remove final "
+    HERE @ 1 - HERE !
+    1 -
+  SWAP C! ;
+
+( Compile the given string into the current word directly. )
+: STORE-STRING ( str len -- )
   BEGIN
     OVER C@ C,
     SWAP 1 + SWAP
   1 - DUP 0 = UNTIL
   DROP DROP ;
 
-S" HELLO-ADDR" CREATE
-S" Hello!" DUP ROT
-STORE-STRING
-: HELLO
-  ' HELLO-ADDR LIT [ , ] TELL NEWLINE ;
+: NEWLINE 10 EMIT ;
+: SPACE 32 EMIT ;
 
-HELLO
+( Read a number from standard input. )
+: READ-NUMBER READ-WORD PARSE-NUMBER ;
 
-S" 10 FIB = " TELL
-10 FIB .U
-S"  (Expected: 59)" TELL NEWLINE
+: RESTART S" Ready." TELL NEWLINE ;
+RESTART