cl-ast: Move loop expression into unary exprs (with lowest priority)

compiler/cl-ast/src/ast.rs

@@ -392,8 +392,6 @@ pub enum ExprKind {
     Group(Group),
     /// A [Tuple] expression: `(` [`Expr`] (`,` [`Expr`])+ `)`
     Tuple(Tuple),
-    /// A [Loop] expression: `loop` [`Block`]
-    Loop(Loop),
     /// A [While] expression: `while` [`Expr`] [`Block`] [`Else`]?
     While(While),
     /// An [If] expression: `if` [`Expr`] [`Block`] [`Else`]?
@@ -482,6 +480,8 @@ pub enum UnaryKind {
     Deref,
     Neg,
     Not,
+    /// A Loop expression: `loop` [`Block`]
+    Loop,
     /// Unused
     At,
     /// Unused
@@ -570,12 +570,6 @@ pub struct Tuple {
     pub exprs: Vec<Expr>,
 }
 
-/// A [Loop] expression: `loop` [`Block`]
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub struct Loop {
-    pub body: Box<Expr>,
-}
-
 /// A [While] expression: `while` [`Expr`] [`Block`] [`Else`]?
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct While {

compiler/cl-ast/src/ast_impl.rs

@@ -448,7 +448,6 @@ mod display {
                 ExprKind::Block(v) => v.fmt(f),
                 ExprKind::Group(v) => v.fmt(f),
                 ExprKind::Tuple(v) => v.fmt(f),
-                ExprKind::Loop(v) => v.fmt(f),
                 ExprKind::While(v) => v.fmt(f),
                 ExprKind::If(v) => v.fmt(f),
                 ExprKind::For(v) => v.fmt(f),
@@ -542,6 +541,7 @@ mod display {
     impl Display for UnaryKind {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             match self {
+                UnaryKind::Loop => "loop ",
                 UnaryKind::Deref => "*",
                 UnaryKind::Neg => "-",
                 UnaryKind::Not => "!",
@@ -644,13 +644,6 @@ mod display {
         }
     }
 
-    impl Display for Loop {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { body } = self;
-            write!(f, "loop {body}")
-        }
-    }
-
     impl Display for While {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { cond, pass, fail } = self;
@@ -786,7 +779,6 @@ mod convert {
             Block => ExprKind::Block,
             Group => ExprKind::Group,
             Tuple => ExprKind::Tuple,
-            Loop => ExprKind::Loop,
             While => ExprKind::While,
             If => ExprKind::If,
             For => ExprKind::For,

compiler/cl-ast/src/ast_visitor/fold.rs

@@ -339,10 +339,6 @@ pub trait Fold {
         let Tuple { exprs } = t;
         Tuple { exprs: exprs.into_iter().map(|e| self.fold_expr(e)).collect() }
     }
-    fn fold_loop(&mut self, l: Loop) -> Loop {
-        let Loop { body } = l;
-        Loop { body: Box::new(self.fold_expr(*body)) }
-    }
     fn fold_while(&mut self, w: While) -> While {
         let While { cond, pass, fail } = w;
         While {
@@ -552,7 +548,6 @@ pub fn or_fold_expr_kind<F: Fold + ?Sized>(folder: &mut F, kind: ExprKind) -> Ex
         ExprKind::Block(b) => ExprKind::Block(folder.fold_block(b)),
         ExprKind::Group(g) => ExprKind::Group(folder.fold_group(g)),
         ExprKind::Tuple(t) => ExprKind::Tuple(folder.fold_tuple(t)),
-        ExprKind::Loop(l) => ExprKind::Loop(folder.fold_loop(l)),
         ExprKind::While(w) => ExprKind::While(folder.fold_while(w)),
         ExprKind::If(i) => ExprKind::If(folder.fold_if(i)),
         ExprKind::For(f) => ExprKind::For(folder.fold_for(f)),

compiler/cl-ast/src/ast_visitor/visit.rs

@@ -297,10 +297,6 @@ pub trait Visit<'a>: Sized {
         let Tuple { exprs } = t;
         exprs.iter().for_each(|e| self.visit_expr(e))
     }
-    fn visit_loop(&mut self, l: &'a Loop) {
-        let Loop { body } = l;
-        self.visit_expr(body)
-    }
     fn visit_while(&mut self, w: &'a While) {
         let While { cond, pass, fail } = w;
         self.visit_expr(cond);
@@ -476,7 +472,6 @@ pub fn or_visit_expr_kind<'a, V: Visit<'a>>(visitor: &mut V, e: &'a ExprKind) {
         ExprKind::Block(b) => visitor.visit_block(b),
         ExprKind::Group(g) => visitor.visit_group(g),
         ExprKind::Tuple(t) => visitor.visit_tuple(t),
-        ExprKind::Loop(l) => visitor.visit_loop(l),
         ExprKind::While(w) => visitor.visit_while(w),
         ExprKind::If(i) => visitor.visit_if(i),
         ExprKind::For(f) => visitor.visit_for(f),

compiler/cl-ast/src/desugar/while_else.rs

@@ -26,8 +26,8 @@ fn desugar_while(extents: Span, kind: ExprKind) -> ExprKind {
             let break_expr = Expr { extents: fail_span, kind: ExprKind::Break(Break { body }) };
 
             let loop_body = If { cond, pass, fail: Else { body: Some(Box::new(break_expr)) } };
-            let loop_body = Expr { extents, kind: ExprKind::If(loop_body) };
+            let loop_body = ExprKind::If(loop_body);
-            ExprKind::Loop(Loop { body: Box::new(loop_body) })
+            ExprKind::Unary(Unary { kind: UnaryKind::Loop, tail: Box::new(loop_body) })
         }
         _ => kind,
     }

compiler/cl-interpret/src/interpret.rs

@@ -151,7 +151,6 @@ impl Interpret for ExprKind {
             ExprKind::Block(v) => v.interpret(env),
             ExprKind::Group(v) => v.interpret(env),
             ExprKind::Tuple(v) => v.interpret(env),
-            ExprKind::Loop(v) => v.interpret(env),
             ExprKind::While(v) => v.interpret(env),
             ExprKind::If(v) => v.interpret(env),
             ExprKind::For(v) => v.interpret(env),
@@ -323,12 +322,28 @@ impl Interpret for Binary {
 impl Interpret for Unary {
     fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
         let Unary { kind, tail } = self;
-        let operand = tail.interpret(env)?;
         match kind {
-            UnaryKind::Deref => env.call("deref".into(), &[operand]),
+            UnaryKind::Loop => loop {
-            UnaryKind::Neg => env.call("neg".into(), &[operand]),
+                match tail.interpret(env) {
-            UnaryKind::Not => env.call("not".into(), &[operand]),
+                    Err(Error::Break(value)) => return Ok(value),
+                    Err(Error::Continue) => continue,
+                    e => e?,
+                };
+            },
+            UnaryKind::Deref => {
+                let operand = tail.interpret(env)?;
+                env.call("deref".into(), &[operand])
+            }
+            UnaryKind::Neg => {
+                let operand = tail.interpret(env)?;
+                env.call("neg".into(), &[operand])
+            }
+            UnaryKind::Not => {
+                let operand = tail.interpret(env)?;
+                env.call("not".into(), &[operand])
+            }
             UnaryKind::At => {
+                let operand = tail.interpret(env)?;
                 println!("{operand}");
                 Ok(operand)
             }
@@ -505,18 +520,6 @@ impl Interpret for Tuple {
         ))
     }
 }
-impl Interpret for Loop {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { body } = self;
-        loop {
-            match body.interpret(env) {
-                Err(Error::Break(value)) => return Ok(value),
-                Err(Error::Continue) => continue,
-                e => e?,
-            };
-        }
-    }
-}
 impl Interpret for While {
     fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
         let Self { cond, pass, fail } = self;

compiler/cl-parser/src/parser.rs

@@ -843,10 +843,6 @@ impl<'t> Parser<'t> {
             TokenKind::LBrack => self.exprkind_arraylike()?,
             TokenKind::LParen => self.exprkind_tuplelike()?,
             TokenKind::Let => self.parse_let()?.into(),
-            TokenKind::Loop => {
-                self.consume_peeked();
-                Loop { body: self.expr()?.into() }.into()
-            }
             TokenKind::While => ExprKind::While(self.parse_while()?),
             TokenKind::If => ExprKind::If(self.parse_if()?),
             TokenKind::For => ExprKind::For(self.parse_for()?),
@@ -1250,6 +1246,7 @@ impl Precedence {
     }
     pub fn prefix(self) -> Option<((), u8)> {
         match self {
+            Self::Assign => Some(((), self.level())),
             Self::Unary => Some(((), self.level())),
             _ => None,
         }
@@ -1294,6 +1291,7 @@ impl From<UnaryKind> for Precedence {
     fn from(value: UnaryKind) -> Self {
         use UnaryKind as Op;
         match value {
+            Op::Loop => Precedence::Assign,
             Op::Deref | Op::Neg | Op::Not | Op::At | Op::Tilde => Precedence::Unary,
         }
     }
@@ -1311,6 +1309,7 @@ macro operator($($name:ident ($takes:ident => $returns:ident) {$($t:ident => $p:
 
 operator! {
     from_prefix (TokenKind => UnaryKind) {
+        Loop => Loop,
         Star => Deref,
         Minus => Neg,
         Bang => Not,

compiler/cl-repl/examples/yaml.rs

@@ -406,7 +406,6 @@ pub mod yamlify {
                 ExprKind::Empty => {}
                 ExprKind::Group(k) => k.yaml(y),
                 ExprKind::Tuple(k) => k.yaml(y),
-                ExprKind::Loop(k) => k.yaml(y),
                 ExprKind::While(k) => k.yaml(y),
                 ExprKind::If(k) => k.yaml(y),
                 ExprKind::For(k) => k.yaml(y),
@@ -537,12 +536,6 @@ pub mod yamlify {
             y.key("Group").yaml(expr);
         }
     }
-    impl Yamlify for Loop {
-        fn yaml(&self, y: &mut Yamler) {
-            let Self { body } = self;
-            y.key("Loop").yaml(body);
-        }
-    }
     impl Yamlify for While {
         fn yaml(&self, y: &mut Yamler) {
             let Self { cond, pass, fail } = self;