small rework towards TI$ assignment and arrays support

src/basic/engine_variables/assign_variable.s

@@ -7,7 +7,7 @@ assign_variable:
 
 	// Fetch variable name, should be followed by assign operator
 
-	jsr fetch_variable
+	jsr fetch_variable_name
 
 #if HAS_OPCODES_65CE02
 
@@ -26,6 +26,21 @@ assign_variable:
 
 #endif
 
+	// Check for special variables
+
+	jsr is_var_TI_string
+	beq_16 assign_variable_TI_string
+
+	jsr is_var_TI
+	beq_16 do_SYNTAX_error
+
+	jsr is_var_ST
+	beq_16 do_SYNTAX_error
+
+	// Retrieve the variable address
+
+	jsr fetch_variable_find_addr
+
 	// Determine variable type and push it to the stack
 
 	lda #$00

src/basic/engine_variables/assign_variable_TI_string.s

@@ -0,0 +1,10 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+
+assign_variable_TI_string:
+
+	// XXX implement
+
+	jmp do_NOT_IMPLEMENTED_error

src/basic/engine_variables/fetch_variable.s

@@ -9,89 +9,13 @@
 
 fetch_variable:
 
-	// Set default second character and variable type
+	// Start by fetching variable name
 
-	lda #$00
-	sta VARNAM+1
-
-	// Fetch the first character of variable name
-
-	jsr fetch_character_skip_spaces
-	jsr is_AZ
+	jsr fetch_variable_name
 	bcc !+
-
-#if !HAS_OPCODES_65CE02
-	jsr unconsume_character
-#else
-	dew TXTPTR
-#endif
-
-	sec
 	rts
 !:
-	sta VARNAM+0
-
-	// Fetch the (optional) second character
-
-	jsr fetch_character
-	jsr is_09_AZ
-	bcs fetch_variable_check_type
-
-	sta VARNAM+1
-
-	// Fetch the remaining variable characters - ignore them
-!:
-	jsr fetch_character
-	jsr is_09_AZ
-	bcc !-
-
-	// FALLTROUGH
-
-fetch_variable_check_type:
-
-	// Encode variable type within name, as documented in:
-	// - https://sites.google.com/site/h2obsession/CBM/basic/variable-format
-
-	cmp #$24                           // '$'
-	beq fetch_variable_type_string
-	cmp #$25                           // '%'
-	beq fetch_variable_type_integer
-
-	// FALLTORUGH
-
-fetch_variable_type_float:
-
-#if !HAS_OPCODES_65CE02
-	jsr unconsume_character
-#else
-	dew TXTPTR
-#endif
-
-	jmp_8 fetch_variable_special
-
-fetch_variable_type_integer:
-
-	lda VARNAM+0
-	ora #$80
-	sta VARNAM+0
-
-	lda #$00
-	skip_2_bytes_trash_nvz
-
-	// FALLTROUGH
-
-fetch_variable_type_string:
-
-	lda #$80
-	sta VALTYP
-
-	lda VARNAM+1
-	ora #$80
-	sta VARNAM+1
-
-	// FALLTROUGH
-
-fetch_variable_special:
+	// Handle special variables - TI$, TI, ST
 
 	jsr is_var_TI_string
 	beq_16 fetch_variable_TI_string

src/basic/engine_variables/fetch_variable_name.s

@@ -0,0 +1,99 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Carry set = failure, not recognized variable name
+//
+
+
+fetch_variable_name:
+
+	// Set default second character and variable type
+
+	lda #$00
+	sta VARNAM+1
+
+	// Fetch the first character of variable name
+
+	jsr fetch_character_skip_spaces
+	jsr is_AZ
+	bcc !+
+
+#if !HAS_OPCODES_65CE02
+	jsr unconsume_character
+#else
+	dew TXTPTR
+#endif
+
+	sec
+	rts
+!:
+	sta VARNAM+0
+
+	// Fetch the (optional) second character
+
+	jsr fetch_character
+	jsr is_09_AZ
+	bcs fetch_variable_check_type
+
+	sta VARNAM+1
+
+	// Fetch the remaining variable characters - ignore them
+!:
+	jsr fetch_character
+	jsr is_09_AZ
+	bcc !-
+
+	// FALLTROUGH
+
+fetch_variable_check_type:
+
+	// Encode variable type within name, as documented in:
+	// - https://sites.google.com/site/h2obsession/CBM/basic/variable-format
+
+	cmp #$24                           // '$'
+	beq fetch_variable_type_string
+	cmp #$25                           // '%'
+	beq fetch_variable_type_integer
+
+	// FALLTORUGH
+
+fetch_variable_type_float:
+
+#if !HAS_OPCODES_65CE02
+	jsr unconsume_character
+#else
+	dew TXTPTR
+#endif
+
+	jmp_8 fetch_variable_name_check_array
+
+fetch_variable_type_integer:
+
+	lda VARNAM+0
+	ora #$80
+	sta VARNAM+0
+
+	lda #$00
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
+
+fetch_variable_type_string:
+
+	lda #$80
+	sta VALTYP
+
+	lda VARNAM+1
+	ora #$80
+	sta VARNAM+1
+
+	// FALLTROUGH
+
+fetch_variable_name_check_array:
+
+	// XXX add check for array
+
+	clc
+	rts