forth: add number literals support

apps/forth/dict.asm

@@ -42,6 +42,25 @@ sysvarWord:
 	push	hl
 	jp	exit
 
+; This is not a word, but a number literal. This works a bit differently than
+; others: PF means nothing and the actual number is placed next to the
+; numberWord reference in the compiled word list. What we need to do to fetch
+; that number is to play with the Return stack: We pop it, read the number, push
+; it to the Parameter stack and then push an increase Interpreter Pointer back
+; to RS.
+numberWord:
+	call	popRS
+	ld	e, (hl)
+	inc	hl
+	ld	d, (hl)
+	inc	hl
+	call	pushRS
+	push	de
+	jp	exit
+NUMBER:
+	.dw	numberWord
+
+
 ; ( R:I -- )
 EXIT:
 	.db "EXIT", 0, 0, 0, 0
@@ -127,10 +146,7 @@ DEFINE:
 .end:
 	; end chain with EXIT
 	ld	hl, EXIT+CODELINK_OFFSET
-	ld	(iy), l
-	inc	iy
-	ld	(iy), h
-	inc	iy
+	call	wrCompHL
 	ld	(HERE), iy
 	jp	exit
 .issemicol:

apps/forth/glue.asm

@@ -3,6 +3,7 @@ jp	forthMain
 
 .inc "core.asm"
 .inc "lib/util.asm"
+.inc "lib/parse.asm"
 .inc "lib/ari.asm"
 .inc "lib/fmt.asm"
 .equ FORTH_RAMSTART RAMSTART

apps/forth/util.asm

@@ -74,21 +74,34 @@ find:
 	inc	a
 	ret
 
+; Write compiled data from HL into IY, advancing IY at the same time.
+wrCompHL:
+	ld	(iy), l
+	inc	iy
+	ld	(iy), h
+	inc	iy
+	ret
+
 ; Compile word string at (HL) and write down its compiled version in IY,
 ; advancing IY to the byte next to the last written byte.
 ; Set Z on success, unset on failure.
 compile:
 	call	find
+	jr	nz, .maybeNum
 	ret	nz
 	; DE is a word offset, we need a code link
 	ld	hl, CODELINK_OFFSET
 	add	hl, de
-	ld	(iy), l
-	inc	iy
-	ld	(iy), h
-	inc	iy
 	xor	a	; set Z
-	ret
+	jr	wrCompHL
+.maybeNum:
+	call	parseLiteral
+	ret	nz
+	; a valid number!
+	ld	hl, NUMBER
+	call	wrCompHL
+	ex	de, hl		; number in HL
+	jr	wrCompHL
 
 ; Spit name + prev in (HERE) and adjust (HERE) and (CURRENT)
 ; HL points to new (HERE)