Fix support of augmented assignment with no rvalue. Fixes GH-1.

src/ast.rs

@@ -327,6 +327,8 @@ pub enum Statement {
  Expressions(Vec<Expression>),
  // `lhs = rhs1 = rhs2` -> `lhs, vec![rhs1, rhs2]`
  Assignment(Vec<Expression>, Vec<Vec<Expression>>),
+ // `lhs: type` -> `lhs, type`
+ TypeAnnotation(Vec<Expression>, Expression),
  // `lhs: type = rhs` -> `lhs, type, rhs`
  TypedAssignment(Vec<Expression>, Expression, Vec<Expression>),
  // `lhs += rhs` -> `lhs, AugAssignOp::Add, rhs`

src/statements.rs

@@ -64,13 +64,17 @@ named!(expr_stmt<StrSpan, Statement>,
  do_parse!(
  lhs: call!(ExpressionParser::<NewlinesAreNotSpaces>::testlist_star_expr) >>
  r: ws_nonl!(alt!(
- // Case 1: "foo: bar = baz"
+ // Case 1: "foo: bar = baz" and "foo: bar"
  do_parse!(
  char!(':') >>
  typed: call!(ExpressionParser::<NewlinesAreNotSpaces>::test) >>
- char!('=') >>
- rhs: call!(ExpressionParser::<NewlinesAreNotSpaces>::test) >> (
- Statement::TypedAssignment(lhs.clone(), *typed, vec![*rhs])
+ rhs: opt!(ws_nonl!(preceded!(char!('='),
+ call!(ExpressionParser::<NewlinesAreNotSpaces>::test)
+ ))) >> (
+ match rhs {
+ None => Statement::TypeAnnotation(lhs.clone(), *typed),
+ Some(rhs) => Statement::TypedAssignment(lhs.clone(), *typed, vec![*rhs]),
+ }
  )
  )
 
@@ -974,6 +978,18 @@ mod tests {
  )));
  }
 
+ #[test]
+ fn test_typeannotation() {
+ assert_parse_eq(small_stmt(make_strspan("foo: bar")), Ok((make_strspan(""),
+ Statement::TypeAnnotation(
+ vec![
+ Expression::Name("foo".to_string()),
+ ],
+ Expression::Name("bar".to_string()),
+ )
+ )));
+ }
+
  #[test]
  fn test_augassign() {
  assert_parse_eq(small_stmt(make_strspan("foo:bar = baz")), Ok((make_strspan(""),

src/visitors/printer.rs

@@ -113,6 +113,11 @@ fn format_statement(indent: usize, stmt: &Statement) -> String {
  }
  s.push_str("\n");
  },
+ Statement::TypeAnnotation(ref lhs, ref typed) => {
+ s.push_str(&format!("{}: {}\n",
+ comma_join(lhs.iter().map(format_expr)),
+ format_expr(typed)));
+ },
  Statement::TypedAssignment(ref lhs, ref typed, ref rhs) => {
  s.push_str(&format!("{}:{} = {}\n",
  comma_join(lhs.iter().map(format_expr)),