feature: parser

parser/ast.go

@@ -1 +1,52 @@
 package parser
+
+import "sfdl/scanner"
+
+type ExprNode struct {
+	Op    scanner.TokenType
+	Left  *ExprNode
+	Right *ExprNode
+	Value float64
+	Func  func(float64) float64
+}
+
+func NewConstNode(v float64) *ExprNode {
+	return &ExprNode{
+		Op:    scanner.CONST_ID,
+		Value: v,
+	}
+}
+
+func NewTNode() *ExprNode {
+	return &ExprNode{
+		Op: scanner.T,
+	}
+}
+
+func NewFuncNode(fn func(float64) float64, child *ExprNode) *ExprNode {
+	return &ExprNode{
+		Op:   scanner.FUNC,
+		Left: child,
+		Func: fn,
+	}
+}
+
+func NewBinaryNode(op scanner.TokenType, left, right *ExprNode) *ExprNode {
+	return &ExprNode{
+		Op:    op,
+		Left:  left,
+		Right: right,
+	}
+}
+
+func NewUnaryNode(op scanner.TokenType, child *ExprNode) *ExprNode {
+	if op == scanner.PLUS {
+		return child
+	}
+	// -x -> 0 - x
+	if op == scanner.MINUS {
+		zero := NewConstNode(0)
+		return NewBinaryNode(scanner.MINUS, zero, child)
+	}
+	return child
+}