Implemented infinite loops

src/build/VariableDefinition.go

@@ -0,0 +1,55 @@
+package build
+
+import (
+	"git.akyoto.dev/cli/q/src/build/expression"
+	"git.akyoto.dev/cli/q/src/build/token"
+	"git.akyoto.dev/cli/q/src/errors"
+)
+
+// CompileVariableDefinition compiles a variable definition.
+func (f *Function) CompileVariableDefinition(expr *expression.Expression) error {
+	if len(expr.Children) < 2 {
+		return errors.New(errors.MissingAssignValue, f.File, expr.LastChild().Token.End())
+	}
+
+	name := expr.Children[0].Token.Text()
+
+	if f.identifierExists(name) {
+		return errors.New(&errors.VariableAlreadyExists{Name: name}, f.File, expr.Children[0].Token.Position)
+	}
+
+	value := expr.Children[1]
+
+	err := value.EachLeaf(func(leaf *expression.Expression) error {
+		if leaf.Token.Kind == token.Identifier && !f.identifierExists(leaf.Token.Text()) {
+			return errors.New(&errors.UnknownIdentifier{Name: leaf.Token.Text()}, f.File, leaf.Token.Position)
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		return err
+	}
+
+	reg, exists := f.CPU.FindFree()
+
+	if !exists {
+		panic("no free registers")
+	}
+
+	f.ExpressionToRegister(value, reg)
+	f.CPU.Use(reg)
+
+	f.Variables[name] = &Variable{
+		Name:     name,
+		Register: reg,
+	}
+
+	return nil
+}
+
+// isVariableDefinition returns true if the expression is a variable definition.
+func isVariableDefinition(expr *expression.Expression) bool {
+	return expr.Token.Kind == token.Operator && expr.Token.Text() == ":="
+}