more work on variables support

src/basic/basic_commands/cmd_let.s

@@ -12,6 +12,73 @@ cmd_let:
 	jsr injest_assign
 	bcs_16 do_SYNTAX_error
 
+	// Determine variable type and push it to the stack
+
+	lda #$00
+	clc
+	bit VARNAM+0
+	bpl !+
+	adc #$01
+!:
+	bit VARNAM+1
+	bpl !+
+	adc #$80
+!:
+	pha
+
+	// Push the VARPNT to the stack - it might get overridden
+
+	lda VARPNT+0
+	pha
+	lda VARPNT+1
+	pha
+
+	// Evaluate the expression
+
+	jsr FRMEVL
+
+	// Restore VARPNT
+
+	pla
+	sta VARPNT+1
+	pla
+	sta VARPNT+0
+
+	// Determine what to assign
+
+	pla
+	bmi cmd_let_assign_string
+	beq cmd_let_assign_float
+
+	// FALLTROUGH
+
+	// XXX integer and float probably have much in common
+
+cmd_let_assign_integer:
+
+	lda VALTYP
+	bmi_16 do_TYPE_MISMATCH_error
+
+	// XXX finish the implementation
+
+	jmp do_NOT_IMPLEMENTED_error
+
+cmd_let_assign_float:
+
+	lda VALTYP
+	bmi_16 do_TYPE_MISMATCH_error
+
+	// XXX finish the implementation
+
+	jmp do_NOT_IMPLEMENTED_error
+
+cmd_let_assign_string:
+
+	// Check if value type matches
+	
+	lda VALTYP
+	bpl_16 do_TYPE_MISMATCH_error
+
 	// XXX finish the implementation
 
 	jmp do_NOT_IMPLEMENTED_error