lib/parse: decimal ending with a whitespace are now valid

Also, make empty strings be parsed as invalid by parseDecimal.

apps/basic/glue.asm

@@ -12,6 +12,7 @@
 
 	jp	basStart
 
+.inc "lib/util.asm"
 .inc "lib/parse.asm"
 .equ	BAS_RAMSTART	USER_RAMSTART
 .inc "basic/main.asm"

apps/lib/parse.asm

@@ -1,6 +1,3 @@
-; *** Requirements ***
-; None
-;
 ; *** Code ***
 
 ; Parse the decimal char at A and extract it's 0-9 numerical value. Put the
@@ -15,31 +12,34 @@
 ; Parse string at (HL) as a decimal value and return value in IX under the
 ; same conditions as parseLiteral.
 ; Sets Z on success, unset on error.
+; To parse successfully, all characters following HL must be digits and those
+; digits must form a number that fits in 16 bits. To end the number, both \0
+; and whitespaces (0x20 and 0x09) are accepted. There must be at least one
+; digit in the string.
 
 parseDecimal:
 	push 	hl
 
-	ld 	a, (hl)
+	ld	a, (hl)
 	add	a, 0xff-'9'	; maps '0'-'9' onto 0xf6-0xff
 	sub	0xff-9		; maps to 0-9 and carries if not a digit
+	jr	c, .error	; not a digit on first char? error
 	exx		; preserve bc, hl, de
 	ld	h, 0
 	ld	l, a	; load first digit in without multiplying
 	ld	b, 3	; Carries can only occur for decimals >=5 in length
-	jr	c, .end
 
 .loop:
 	exx
 	inc hl
 	ld a, (hl)
 	exx
-	
+
 	; inline parseDecimalDigit
 	add	a, 0xff-'9'	; maps '0'-'9' onto 0xf6-0xff
 	sub	0xff-9		; maps to 0-9 and carries if not a digit
-	
 	jr	c, .end
-	
+
 	add	hl, hl	; x2
 	ld	d, h
 	ld	e, l		; de is x2
@@ -74,4 +74,9 @@ parseDecimal:
 	push	hl \ pop ix
 	exx	; restore original de and bc
 	pop	hl
-	ret
+	ret	z
+	; A is not 0? Ok, but if it's a space, we're happy too.
+	jp	isSep
+.error:
+	pop	hl
+	jp	unsetZ

apps/lib/util.asm

@@ -1,3 +1,10 @@
+; Sets Z is A is ' ' or '\t'
+isSep:
+	cp	' '
+	ret	z
+	cp	0x09
+	ret
+
 ; Copy string from (HL) in (DE), that is, copy bytes until a null char is
 ; encountered. The null char is also copied.
 ; HL and DE point to the char right after the null char.

apps/zasm/parse.asm

@@ -195,6 +195,9 @@ parseNumberOrSymbol:
 	; matter that we didn't find our symbol. Return success anyhow.
 	; Otherwise return error. Z is already unset, so in fact, this is the
 	; same as jumping to zasmIsFirstPass
+	; however, before we do, load IX with zero. Returning dummy non-zero
+	; values can have weird consequence (such as false overflow errors).
+	ld	ix, 0
 	jp	zasmIsFirstPass
 
 .returnPC:

apps/zasm/tok.asm

@@ -29,13 +29,6 @@ isLineEnd:
 	cp	'\'
 	ret
 
-; Sets Z is A is ' ' '\t'
-isSep:
-	cp	' '
-	ret	z
-	cp	0x09
-	ret
-
 ; Sets Z is A is ' ', ',', ';', CR, LF, or null.
 isSepOrLineEnd:
 	call	isSep

tools/tests/unit/test_parse_z.asm

@@ -100,29 +100,11 @@ testLiteral:
 	call	nexttest
 	ret
 
-; 2b int, 6b str, null-padded
-tblDecimalValid:
-	.dw	99
-	.db	"99", 0, 0, 0, 0
-	.dw	65535
-	.db	"65535", 0
-
-; 7b strings, null-padded
-tblDecimalInvalid:
-	; TODO: make a null string parse as an invalid decimal
-	; null string is invalid
-	;.db	0, 0, 0, 0, 0, 0, 0
-	; too big, 5 chars
-	.db	"65536", 0, 0
-	.db	"99999", 0, 0
-	; too big, 6 chars with rightmost chars being within bound
-	.db	"111111", 0
-
 testDecimal:
 
 ; test valid cases. We loop through tblDecimalValid for our cases
-	ld	b, 2
-	ld	hl, tblDecimalValid
+	ld	b, 5
+	ld	hl, .valid
 
 .loop1:
 	push	hl	; --> lvl 1
@@ -147,8 +129,8 @@ testDecimal:
 	call	nexttest
 
 ; test invalid cases. We loop through tblDecimalInvalid for our cases
-	ld	b, 3
-	ld	hl, tblDecimalInvalid
+	ld	b, 4
+	ld	hl, .invalid
 
 .loop2:
 	call	parseDecimal
@@ -159,6 +141,34 @@ testDecimal:
 	call	nexttest
 	ret
 
+; 2b int, 6b str, null-padded
+.valid:
+	.dw	99
+	.db	"99", 0, 0, 0, 0
+	.dw	65535
+	.db	"65535", 0
+	; Space is also accepted as a number "ender"
+	.dw	42
+	.db	"42 x", 0, 0
+	; Tab too
+	.dw	42
+	.db	"42", 0x09, 'x', 0, 0
+	; A simple "0" works too!
+	.dw	0
+	.db	'0', 0, 0, 0, 0, 0
+
+
+; 7b strings, null-padded
+.invalid:
+	; null string is invalid
+	.db	0, 0, 0, 0, 0, 0, 0
+	; too big, 5 chars
+	.db	"65536", 0, 0
+	.db	"99999", 0, 0
+	; too big, 6 chars with rightmost chars being within bound
+	.db	"111111", 0
+
+
 nexttest:
 	ld	a, (testNum)
 	inc	a