parser: support else statements

phpast/samples/if.php

@@ -0,0 +1,7 @@
+<?php
+
+if($foo) {
+ return $foo;
+} else {
+ return $foo;
+}

trunk_parser/src/ast.rs

@@ -170,6 +170,7 @@ pub enum Statement {
  If {
  condition: Expression,
  then: Block,
+ r#else: Option<Block>
  },
  Return {
  value: Option<Expression>,

trunk_parser/src/parser/mod.rs

@@ -354,7 +354,22 @@ impl Parser {
  expect!(self, TokenKind::RightBrace, "expected }");
  }
 
- Statement::If { condition, then }
+ if self.current.kind != TokenKind::Else {
+ return Ok(Statement::If { condition, then, r#else: None });
+ }
+
+ expect!(self, TokenKind::Else, "expected else");
+
+ expect!(self, TokenKind::LeftBrace, "expected {");
+
+ let mut r#else = Block::new();
+ while ! self.is_eof() && self.current.kind != TokenKind::RightBrace {
+ r#else.push(self.statement()?);
+ }
+
+ expect!(self, TokenKind::RightBrace, "expected }");
+
+ Statement::If { condition, then, r#else: Some(r#else) }
  },
  TokenKind::Class => self.class()?,
  TokenKind::Echo => {
@@ -1117,6 +1132,7 @@ mod tests {
  then: vec![
  Statement::Return { value: Some(Expression::Variable("n".into())) }
  ],
+ r#else: None
  },
  Statement::Return {
  value: Some(Expression::Infix(
@@ -1149,16 +1165,28 @@ mod tests {
 
  #[test]
  fn one_liner_if_statement() {
- assert_ast("\
- <?php
+ assert_ast("<?php if($foo) return $foo;", &[
+ Statement::If {
+ condition: Expression::Variable("foo".into()),
+ then: vec![
+ Statement::Return { value: Some(Expression::Variable("foo".into())) }
+ ],
+ r#else: None
+ },
+ ]);
+ }
 
- if($name)
- return $name;", &[
+ #[test]
+ fn if_else_statement() {
+ assert_ast("<?php if($foo) { return $foo; } else { return $foo; }", &[
  Statement::If {
- condition: Expression::Variable("name".into()),
+ condition: Expression::Variable("foo".into()),
  then: vec![
- Statement::Return { value: Some(Expression::Variable("name".into())) }
+ Statement::Return { value: Some(Expression::Variable("foo".into())) }
  ],
+ r#else: Some(vec![
+ Statement::Return { value: Some(Expression::Variable("foo".into())) }
+ ])
  },
  ]);
  }