initial commit [141.14.140.180,mike]

ast.go

@@ -0,0 +1,63 @@
+package main
+
+// Node represents an AST node.
+type Node interface {
+	isNode()
+}
+
+type Expr interface {
+	Node
+	isExpr()
+}
+
+// BinaryExpr represents a binary operation.
+type BinaryExpr struct {
+	Op    string
+	Left  Expr
+	Right Expr
+}
+
+func (e *BinaryExpr) isNode() {}
+func (e *BinaryExpr) isExpr() {}
+
+// UnaryExpr represents a unary operation (+, -, ~).
+type UnaryExpr struct {
+	Op   string
+	Expr Expr
+}
+
+func (e *UnaryExpr) isNode() {}
+func (e *UnaryExpr) isExpr() {}
+
+// NumberExpr represents a numeric literal.
+type NumberExpr struct {
+	Value string // parsed as decimal later
+}
+
+func (e *NumberExpr) isNode() {}
+func (e *NumberExpr) isExpr() {}
+
+// IdentExpr represents an identifier (variable, unit, constant, or currency symbol).
+type IdentExpr struct {
+	Name string
+}
+
+func (e *IdentExpr) isNode() {}
+func (e *IdentExpr) isExpr() {}
+
+// CallExpr represents a function call.
+type CallExpr struct {
+	Func string
+	Args []Expr
+}
+
+func (e *CallExpr) isNode() {}
+func (e *CallExpr) isExpr() {}
+
+// StringExpr represents a string literal.
+type StringExpr struct {
+	Value string
+}
+
+func (e *StringExpr) isNode() {}
+func (e *StringExpr) isExpr() {}