While expression

schala-lang/language/src/parser.rs

@@ -65,7 +65,7 @@ fn bool_literal(text: &str) -> ParseResult<ExpressionKind> {
     value(true, tag("true")),
     value(false, tag("false"))
   ));
-  map(p, ExpressionKind::BoolLiteral)(text)
+  context("Bool literal", map(p, ExpressionKind::BoolLiteral))(text)
 }
 
 fn number_literal(text: &str) -> ParseResult<ExpressionKind> {
@@ -121,8 +121,7 @@ fn literal(text: &str) -> ParseResult<ExpressionKind> {
 }
 
 fn paren_expr(text: &str) -> ParseResult<ExpressionKind> {
-  use nom::character::complete::char;
-  context("Paren expression", delimited(char('('), expression_kind, char(')')))(text)
+  context("Paren expression", delimited(tag("("), ws(expression_kind), tag(")")))(text)
 }
 
 fn prefix_op(text: &str) -> ParseResult<PrefixOp> {
@@ -148,12 +147,30 @@ fn primary_expr(text: &str) -> ParseResult<ExpressionKind> {
   alt((
     if_expr,
     for_expr,
+    while_expr,
     literal,
     paren_expr,
     identifier_expr,
   ))(text)
 }
 
+fn while_expr(text: &str) -> ParseResult<ExpressionKind> {
+  let p = preceded(tag("while"), tuple((ws(while_cond), ws(block))));
+  let m = map(p, |(condition, body)| {
+    let condition = condition.map(Box::new);
+    ExpressionKind::WhileExpression {condition, body}
+  });
+  context("While expression", m)(text)
+}
+
+fn while_cond(text: &str) -> ParseResult<Option<Expression>> {
+  //TODO support is constructs?
+  context("While condition",
+   map(opt(ws(expression_kind)),
+   |maybe_expr_kind| maybe_expr_kind.map(|kind| Expression::new(ItemId::new(0), kind)))
+  )(text)
+}
+
 fn for_expr(text: &str) -> ParseResult<ExpressionKind> {
   //TODO do I need something like no struct literal here?
   let en = alt((

schala-lang/language/src/parsing/test.rs

@@ -618,13 +618,13 @@ fn more_advanced_lambdas() {
 #[test]
 fn while_expr() {
   parse_test_wrap_ast! {
-    "while { }",
-    exst!(WhileExpression { condition: None, body: vec![] })
+    "while { 3 }",
+    exst!(WhileExpression { condition: None, body: vec![ exst!(s "3")] })
   }
 
   parse_test_wrap_ast! {
-    "while a == b { }",
-    exst!(WhileExpression { condition: Some(bx![ex![binexp!("==", val!("a"), val!("b"))]]), body: vec![] })
+    "while a == b { 3 }",
+    exst!(WhileExpression { condition: Some(bx![ex![binexp!("==", val!("a"), val!("b"))]]), body: vec![ exst!(s "3")] })
   }
 }