chapter 2.6

1 files changed, 62 insertions, 0 deletions

diff --git a/ast/ast.odin b/ast/ast.odin
new file mode 100644
index 0000000..67039a3
--- /dev/null
+++ b/ast/ast.odin
@@ -0,0 +1,62 @@
+package ast
+
+import "../token"
+
+Node :: union {
+	Program,
+	Statement,
+	Expression,
+}
+
+Program :: struct {
+	statements: []Statement,
+}
+
+Statement :: union {
+	Let_Statement,
+    Return_Statement,
+}
+
+Let_Statement :: struct {
+	token: token.Token,
+	name:  Identifier,
+	value: Expression,
+}
+
+Return_Statement :: struct {
+    token: token.Token,
+    return_value: Expression,
+}
+
+Expression :: union {
+	Identifier,
+}
+
+Identifier :: struct {
+	token: token.Token,
+	value: string,
+}
+
+
+token_literal :: proc(node: Node) -> (literal: string) {
+	switch n in node {
+	case Program:
+		if len(n.statements) > 0 {
+			stmt: Node = n.statements[0]
+			literal = token_literal(stmt)
+		}
+	case Statement:
+		switch s in n {
+		case Let_Statement:
+			literal = token.literal(s.token)
+        case Return_Statement:
+            literal = token.literal(s.token)
+		}
+	case Expression:
+		switch e in n {
+		case Identifier:
+			literal = token.literal(e.token)
+		}
+	}
+	return literal
+}