parser: support top-level constants

trunk_parser/src/parser/mod.rs

@@ -925,6 +925,24 @@ impl Parser {
  self.rbrace()?;
  Statement::Block { body }
  }
+ TokenKind::Const => {
+ self.next();
+
+ // TODO: Support defining multiple constants in one go.
+ let name = self.ident()?;
+
+ expect!(self, TokenKind::Equals, "expected =");
+
+ let value = self.expression(0)?;
+
+ self.semi()?;
+
+ Statement::Constant {
+ name: name.into(),
+ value,
+ flags: vec![],
+ }
+ }
  _ => {
  let expr = self.expression(0)?;
 
@@ -3275,6 +3293,18 @@ mod tests {
  );
  }
 
+ #[test]
+ fn top_level_constant() {
+ assert_ast(
+ "<?php const FOO = 1;",
+ &[Statement::Constant {
+ name: "FOO".into(),
+ value: Expression::Int { i: 1 },
+ flags: vec![],
+ }],
+ );
+ }
+
  fn assert_ast(source: &str, expected: &[Statement]) {
  let mut lexer = Lexer::new(None);
  let tokens = lexer.tokenize(source).unwrap();