Reorganized file structure

src/build/ast/Define.go

@@ -0,0 +1,18 @@
+package ast
+
+import (
+	"fmt"
+
+	"git.akyoto.dev/cli/q/src/build/expression"
+	"git.akyoto.dev/cli/q/src/build/token"
+)
+
+// Define represents a variable definition.
+type Define struct {
+	Value *expression.Expression
+	Name  token.Token
+}
+
+func (node *Define) String() string {
+	return fmt.Sprintf("(= %s %s)", node.Name.Text(), node.Value)
+}