From a2bf02556de7af1233aa925f22bf834f0ded7aae Mon Sep 17 00:00:00 2001
From: Hazem Krimi <me@hazemkrimi.tech>
Date: Tue, 28 Apr 2026 11:31:07 +0100
Subject: [PATCH] feat: vm code writing functions

---
 internal/code/code.go | 149 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 149 insertions(+)
 create mode 100644 internal/code/code.go

diff --git a/internal/code/code.go b/internal/code/code.go
new file mode 100644
index 0000000..4d13796
--- /dev/null
+++ b/internal/code/code.go
@@ -0,0 +1,149 @@
+package code
+
+import "fmt"
+
+import "strings"
+
+type Segment int
+type ArithmeticLogicalCommand int
+
+const (
+	CONSTANT Segment = iota
+	ARGUMENT
+	LOCAL
+	STATIC
+	THIS
+	THAT
+	POINTER
+	TEMP
+)
+
+const (
+	ADD ArithmeticLogicalCommand = iota
+	SUB
+	NEG
+	EQ
+	GT
+	LT
+	AND
+	OR
+	NOT
+)
+
+func SegmentText(segment Segment) string {
+	switch segment {
+	case CONSTANT:
+		return "constant"
+	case ARGUMENT:
+		return "argument"
+	case LOCAL:
+		return "local"
+	case STATIC:
+		return "static"
+	case THIS:
+		return "this"
+	case THAT:
+		return "that"
+	case POINTER:
+		return "pointer"
+	case TEMP:
+		return "temp"
+	}
+
+	return "constant"
+}
+
+func WritePush(output *strings.Builder, segment Segment, index int) error {
+	if _, err := output.WriteString("push " + SegmentText(segment) + " " + fmt.Sprint(index)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WritePop(output *strings.Builder, segment Segment, index int) error {
+	if _, err := output.WriteString("pop " + SegmentText(segment) + " " + fmt.Sprint(index)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WriteArithmeticLogical(output *strings.Builder, command ArithmeticLogicalCommand) error {
+	var commandText string
+
+	switch command {
+	case ADD:
+		commandText = "add"
+	case SUB:
+		commandText = "sub"
+	case NEG:
+		commandText = "neg"
+	case EQ:
+		commandText = "eq"
+	case GT:
+		commandText = "gt"
+	case LT:
+		commandText = "lt"
+	case AND:
+		commandText = "and"
+	case OR:
+		commandText = "or"
+	case NOT:
+		commandText = "not"
+	}
+
+	if _, err := output.WriteString(commandText); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WriteLabel(output *strings.Builder, label string) error {
+	if _, err := output.WriteString("label " + label); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WriteGoto(output *strings.Builder, label string) error {
+	if _, err := output.WriteString("goto " + label); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WriteIfGoto(output *strings.Builder, label string) error {
+	if _, err := output.WriteString("if-goto " + label); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WriteCall(output *strings.Builder, function string, args int) error {
+	if _, err := output.WriteString("call " + function + " " + fmt.Sprint(args)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WriteFunction(output *strings.Builder, function string, params int) error {
+	if _, err := output.WriteString("function " + function + " " + fmt.Sprint(params)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func WriteReturn(output *strings.Builder) error {
+	if _, err := output.WriteString("return"); err != nil {
+		return err
+	}
+
+	return nil
+}