Implemented assignments

src/build/Assignment.go

@@ -0,0 +1,38 @@
+package build
+
+import (
+	"strconv"
+
+	"git.akyoto.dev/cli/q/src/build/asm"
+	"git.akyoto.dev/cli/q/src/build/expression"
+	"git.akyoto.dev/cli/q/src/errors"
+)
+
+// CompileAssignment compiles an assignment.
+func (f *Function) CompileAssignment(expr *expression.Expression) error {
+	name := expr.Children[0].Token.Text()
+	number, _ := strconv.Atoi(expr.Children[1].Token.Text())
+	register := f.Variables[name].Register
+
+	switch expr.Token.Text() {
+	case "=":
+		f.ExpressionToRegister(expr.Children[1], register)
+
+	case "+=":
+		f.Assembler.RegisterNumber(asm.ADD, register, number)
+
+	case "-=":
+		f.Assembler.RegisterNumber(asm.SUB, register, number)
+
+	case "*=":
+		f.Assembler.RegisterNumber(asm.MUL, register, number)
+
+	case "/=":
+		f.Assembler.RegisterNumber(asm.DIV, register, number)
+
+	default:
+		return errors.New(&errors.InvalidInstruction{Instruction: expr.Token.Text()}, f.File, expr.Token.Position)
+	}
+
+	return nil
+}