add memory.fill/memory.copy intrinsics

README.md

@@ -89,16 +89,25 @@ For floating point numbers, only the most basic decimal format is currently impl
 0.464, 3.141, -10.0
 ```
 
-String literals exist in a very basic form. No escape character implemented yet.
+String literals are used for include paths, import names and as literal strings in the data section. The following escapes are supported:
+| Escape | Result | Comment                            |
+| `\"`   | `"`    |                                    |
+| `\'`   | `'`    |                                    |
+| `\t`   | 8      |                                    |
+| `\n`   | 10     |                                    |
+| `\r`   | 13     |                                    |
+| `\N`   | 0x0N   | (Can't be followed by a hex digit) |
+| `\NN`  | 0xNN   |                                    |
 
 ```
 "env.memory", "Hello World!"
 
-this does not work, yet:
-
 "one line\nsecond line", "They said: \"Enough!\""
 ```
 
+Character literals are enclosed in single quotes `'` and support the same escapes as strings. They can contain up to 4 characters and evaluate to the
+little-endian representation of these characters. For examples: `'A'` evaluates to `0x41`, `'hi'` evaluates to 0x6968, and `'Crly'` to 0x7a6c7243.
+
 ### Imports
 
 WebAssembly imports are specified with a module and a name. In CurlyWas you give them inside a single string literal, seperated by a dot. So a module `env` and name `printString` would be written `"env.printString"`.
@@ -295,6 +304,9 @@ So for example this block evaluates to 12:
 
 Blocks are used as function bodies and in flow control (`if`, `block`, `loop`), but can also used at any point inside an expression.
 
+Variable re-assignments of the form `name = name <op> expression` can be shortened to `name <op>= expression`, for example `x += 1` to increment `x` by one. This works for all arithmetic, bit and shift operators.
+The same is allowed for `name := name <op> expression`, ie. `x +:= 1` increments `x` and returns the new value.
+
 #### Flow control
 
 `if condition_expression { if_true_block } [else {if_false_block}]` executes the `if_true_block` if the condition evaluates to a non-zero integer and
@@ -304,6 +316,17 @@ the `if_false_block` otherwise (if it exists). It can also be used as an express
 let a = if 0 { 2 } else { 3 }; // assigns 3 to a
 ```
 
+If the `if_false_block` contains exactly one `if` expression or statement you may omit the curly braces, writing `else if` chains like:
+```
+if x == 0 {
+    doOneThing()
+} else if x == 1 {
+    doThatOtherThing()
+} else {
+    keepWaiting()
+}
+```
+
 `block name { ... }` opens a named block scope. A branch statement can be used to jump to the end of the block. Currently, `block` can only be used
 as a statement, returning a value from the block is not yet supported.
 

examples/microw8/warptunnel.cwa

@@ -1,15 +1,16 @@
 import "env.memory" memory(2);
+import "env.time" fn time() -> f32;
 
-export fn tic(time: i32) {
+export fn upd() {
     let i: i32;
     loop pixels {
         let lazy x = (i % 320) as f32 - 160.1;
         let lazy y = (i / 320 - 120) as f32;
-        let lazy dist = 10000.0 / (x*x + y*y);
+        let lazy dist = 1024_f / (x*x + y*y);
-        let lazy t = time as f32 / 20 as f32;
+        let inline t = time() * 4_f;
 
-        i?120 = (x * dist + t) as i32 ^ (y * dist + t) as i32;
+        i?120 = (x * dist + t) as i32 ^ (y * dist + t) as i32 | -32;
 
-        branch_if (i := i + 1) < 320*240: pixels
+        branch_if (i +:= 1) < 320*240: pixels
     }
 }

examples/wasm4/skipahead.cwa

@@ -18,14 +18,14 @@ fn rng(state: i32) -> i32 {
 }
 
 fn set_color(color: i32) -> i32 {
-    ?20 = color;
+    0?20 = color;
     6
 }
 
 export fn update() {
     let y: i32;
     let score = pz;
-    let lazy pad = ?22;
+    let lazy pad = 0?22;
     let lazy zero = 0.0;
 
     let lazy control_speed = 0.03;
@@ -33,7 +33,7 @@ export fn update() {
     f = f * 0.7;
 
     loop lines {
-        ?(8003-y) = (score := score / 10) % 10 + 48;
+        (8003-y)?0 = (score := score / 10) % 10 + 48;
         let lazy z = (4000 / (y := y + 1) + pz) / 20;
         let lazy x = (rng(rng(rng(rng(z)))) >> 30) as f32 - px;
         let lazy w = 9 as f32 / sqrt(z as f32);

src/intrinsics.rs

@@ -1,9 +1,11 @@
 use crate::ast::Type;
-use std::collections::HashMap;
 use enc::MemArg;
+use std::collections::HashMap;
 use wasm_encoder as enc;
 
-pub struct Intrinsics(HashMap<String, HashMap<Vec<Type>, (Type, enc::Instruction<'static>)>>);
+pub struct Intrinsics(
+    HashMap<String, HashMap<Vec<Type>, (Option<Type>, enc::Instruction<'static>)>>,
+);
 
 impl Intrinsics {
     pub fn new() -> Intrinsics {
@@ -12,14 +14,11 @@ impl Intrinsics {
         i
     }
 
-    pub fn find_types(
+    pub fn find_types(&self, name: &str) -> Option<HashMap<Vec<Type>, Option<Type>>> {
-        &self,
-        name: &str,
-    ) -> Option<HashMap<Vec<Type>, Option<Type>>> {
         self.0.get(name).map(|types| {
             types
                 .iter()
-                .map(|(params, (ret, _))| (params.clone(), Some(*ret)))
+                .map(|(params, (ret, _))| (params.clone(), *ret))
                 .collect()
         })
     }
@@ -34,87 +33,121 @@ impl Intrinsics {
     fn add_instructions(&mut self) {
         use enc::Instruction as I;
         use Type::*;
-        self.inst("i32.rotl", &[I32, I32], I32, I::I32Rotl);
+        self.inst("i32.rotl", &[I32, I32], Some(I32), I::I32Rotl);
-        self.inst("i32.rotr", &[I32, I32], I32, I::I32Rotr);
+        self.inst("i32.rotr", &[I32, I32], Some(I32), I::I32Rotr);
-        self.inst("i32.clz", &[I32], I32, I::I32Clz);
+        self.inst("i32.clz", &[I32], Some(I32), I::I32Clz);
-        self.inst("i32.ctz", &[I32], I32, I::I32Ctz);
+        self.inst("i32.ctz", &[I32], Some(I32), I::I32Ctz);
-        self.inst("i32.popcnt", &[I32], I32, I::I32Popcnt);
+        self.inst("i32.popcnt", &[I32], Some(I32), I::I32Popcnt);
 
-        self.inst("i64.rotl", &[I64, I64], I64, I::I64Rotl);
+        self.inst("i64.rotl", &[I64, I64], Some(I64), I::I64Rotl);
-        self.inst("i64.rotr", &[I64, I64], I64, I::I64Rotr);
+        self.inst("i64.rotr", &[I64, I64], Some(I64), I::I64Rotr);
-        self.inst("i64.clz", &[I64], I64, I::I64Clz);
+        self.inst("i64.clz", &[I64], Some(I64), I::I64Clz);
-        self.inst("i64.ctz", &[I64], I64, I::I64Ctz);
+        self.inst("i64.ctz", &[I64], Some(I64), I::I64Ctz);
-        self.inst("i64.popcnt", &[I64], I64, I::I64Popcnt);
+        self.inst("i64.popcnt", &[I64], Some(I64), I::I64Popcnt);
 
-        self.inst("f32/sqrt", &[F32], F32, I::F32Sqrt);
+        self.inst("f32/sqrt", &[F32], Some(F32), I::F32Sqrt);
-        self.inst("f32/min", &[F32, F32], F32, I::F32Min);
+        self.inst("f32/min", &[F32, F32], Some(F32), I::F32Min);
-        self.inst("f32/max", &[F32, F32], F32, I::F32Max);
+        self.inst("f32/max", &[F32, F32], Some(F32), I::F32Max);
-        self.inst("f32/ceil", &[F32], F32, I::F32Ceil);
+        self.inst("f32/ceil", &[F32], Some(F32), I::F32Ceil);
-        self.inst("f32/floor", &[F32], F32, I::F32Floor);
+        self.inst("f32/floor", &[F32], Some(F32), I::F32Floor);
-        self.inst("f32/trunc", &[F32], F32, I::F32Trunc);
+        self.inst("f32/trunc", &[F32], Some(F32), I::F32Trunc);
-        self.inst("f32/nearest", &[F32], F32, I::F32Nearest);
+        self.inst("f32/nearest", &[F32], Some(F32), I::F32Nearest);
-        self.inst("f32/abs", &[F32], F32, I::F32Abs);
+        self.inst("f32/abs", &[F32], Some(F32), I::F32Abs);
-        self.inst("f32.copysign", &[F32, F32], F32, I::F32Copysign);
+        self.inst("f32.copysign", &[F32, F32], Some(F32), I::F32Copysign);
 
-        self.inst("f64/sqrt", &[F64], F64, I::F64Sqrt);
+        self.inst("f64/sqrt", &[F64], Some(F64), I::F64Sqrt);
-        self.inst("f64/min", &[F64, F64], F64, I::F64Min);
+        self.inst("f64/min", &[F64, F64], Some(F64), I::F64Min);
-        self.inst("f64/max", &[F64, F64], F64, I::F64Max);
+        self.inst("f64/max", &[F64, F64], Some(F64), I::F64Max);
-        self.inst("f64/ceil", &[F64], F64, I::F64Ceil);
+        self.inst("f64/ceil", &[F64], Some(F64), I::F64Ceil);
-        self.inst("f64/floor", &[F64], F64, I::F64Floor);
+        self.inst("f64/floor", &[F64], Some(F64), I::F64Floor);
-        self.inst("f64/trunc", &[F64], F64, I::F64Trunc);
+        self.inst("f64/trunc", &[F64], Some(F64), I::F64Trunc);
-        self.inst("f64/nearest", &[F64], F64, I::F64Nearest);
+        self.inst("f64/nearest", &[F64], Some(F64), I::F64Nearest);
-        self.inst("f64/abs", &[F64], F64, I::F64Abs);
+        self.inst("f64/abs", &[F64], Some(F64), I::F64Abs);
-        self.inst("f64.copysign", &[F64, F64], F64, I::F64Copysign);
+        self.inst("f64.copysign", &[F64, F64], Some(F64), I::F64Copysign);
 
-        self.inst("i32.wrap_i64", &[I64], I32, I::I32WrapI64);
+        self.inst("i32.wrap_i64", &[I64], Some(I32), I::I32WrapI64);
-        self.inst("i64.extend_i32_s", &[I32], I64, I::I64ExtendI32S);
+        self.inst("i64.extend_i32_s", &[I32], Some(I64), I::I64ExtendI32S);
-        self.inst("i64.extend_i32_u", &[I32], I64, I::I64ExtendI32U);
+        self.inst("i64.extend_i32_u", &[I32], Some(I64), I::I64ExtendI32U);
 
-        self.inst("i32.trunc_f32_s", &[F32], I32, I::I32TruncF32S);
+        self.inst("i32.trunc_f32_s", &[F32], Some(I32), I::I32TruncF32S);
-        self.inst("i32.trunc_f64_s", &[F64], I32, I::I32TruncF64S);
+        self.inst("i32.trunc_f64_s", &[F64], Some(I32), I::I32TruncF64S);
-        self.inst("i64.trunc_f32_s", &[F32], I64, I::I64TruncF32S);
+        self.inst("i64.trunc_f32_s", &[F32], Some(I64), I::I64TruncF32S);
-        self.inst("i64.trunc_f64_s", &[F64], I64, I::I64TruncF64S);
+        self.inst("i64.trunc_f64_s", &[F64], Some(I64), I::I64TruncF64S);
 
-        self.inst("i32.trunc_f32_u", &[F32], I32, I::I32TruncF32U);
+        self.inst("i32.trunc_f32_u", &[F32], Some(I32), I::I32TruncF32U);
-        self.inst("i32.trunc_f64_u", &[F64], I32, I::I32TruncF64U);
+        self.inst("i32.trunc_f64_u", &[F64], Some(I32), I::I32TruncF64U);
-        self.inst("i64.trunc_f32_u", &[F32], I64, I::I64TruncF32U);
+        self.inst("i64.trunc_f32_u", &[F32], Some(I64), I::I64TruncF32U);
-        self.inst("i64.trunc_f64_u", &[F64], I64, I::I64TruncF64U);
+        self.inst("i64.trunc_f64_u", &[F64], Some(I64), I::I64TruncF64U);
 
-        self.inst("f32.demote_f64", &[F64], F32, I::F32DemoteF64);
+        self.inst("f32.demote_f64", &[F64], Some(F32), I::F32DemoteF64);
-        self.inst("f64.promote_f32", &[F32], F64, I::F64PromoteF32);
+        self.inst("f64.promote_f32", &[F32], Some(F64), I::F64PromoteF32);
 
-        self.inst("f32.convert_i32_s", &[I32], F32, I::F32ConvertI32S);
+        self.inst("f32.convert_i32_s", &[I32], Some(F32), I::F32ConvertI32S);
-        self.inst("f32.convert_i64_s", &[I64], F32, I::F32ConvertI32S);
+        self.inst("f32.convert_i64_s", &[I64], Some(F32), I::F32ConvertI32S);
-        self.inst("f64.convert_i32_s", &[I32], F64, I::F32ConvertI32S);
+        self.inst("f64.convert_i32_s", &[I32], Some(F64), I::F32ConvertI32S);
-        self.inst("f64.convert_i64_s", &[I64], F64, I::F32ConvertI32S);
+        self.inst("f64.convert_i64_s", &[I64], Some(F64), I::F32ConvertI32S);
 
-        self.inst("f32.convert_i32_u", &[I32], F32, I::F32ConvertI32U);
+        self.inst("f32.convert_i32_u", &[I32], Some(F32), I::F32ConvertI32U);
-        self.inst("f32.convert_i64_u", &[I64], F32, I::F32ConvertI32U);
+        self.inst("f32.convert_i64_u", &[I64], Some(F32), I::F32ConvertI32U);
-        self.inst("f64.convert_i32_u", &[I32], F64, I::F32ConvertI32U);
+        self.inst("f64.convert_i32_u", &[I32], Some(F64), I::F32ConvertI32U);
-        self.inst("f64.convert_i64_u", &[I64], F64, I::F32ConvertI32U);
+        self.inst("f64.convert_i64_u", &[I64], Some(F64), I::F32ConvertI32U);
 
-        self.inst("i32.reinterpret_f32", &[F32], I32, I::I32ReinterpretF32);
+        self.inst(
-        self.inst("i64.reinterpret_f64", &[F64], I64, I::I64ReinterpretF64);
+            "i32.reinterpret_f32",
-        self.inst("f32.reinterpret_i32", &[I32], F32, I::F32ReinterpretI32);
+            &[F32],
-        self.inst("f64.reinterpret_i64", &[I64], F64, I::F64ReinterpretI64);
+            Some(I32),
+            I::I32ReinterpretF32,
+        );
+        self.inst(
+            "i64.reinterpret_f64",
+            &[F64],
+            Some(I64),
+            I::I64ReinterpretF64,
+        );
+        self.inst(
+            "f32.reinterpret_i32",
+            &[I32],
+            Some(F32),
+            I::F32ReinterpretI32,
+        );
+        self.inst(
+            "f64.reinterpret_i64",
+            &[I64],
+            Some(F64),
+            I::F64ReinterpretI64,
+        );
 
-        self.inst("i32.extend8_s", &[I32], I32, I::I32Extend8S);
+        self.inst("i32.extend8_s", &[I32], Some(I32), I::I32Extend8S);
-        self.inst("i32.extend16_s", &[I32], I32, I::I32Extend16S);
+        self.inst("i32.extend16_s", &[I32], Some(I32), I::I32Extend16S);
-        self.inst("i64.extend8_s", &[I64], I64, I::I64Extend8S);
+        self.inst("i64.extend8_s", &[I64], Some(I64), I::I64Extend8S);
-        self.inst("i64.extend16_s", &[I64], I64, I::I64Extend16S);
+        self.inst("i64.extend16_s", &[I64], Some(I64), I::I64Extend16S);
-        self.inst("i64.extend32_s", &[I64], I64, I::I64Extend32S);
+        self.inst("i64.extend32_s", &[I64], Some(I64), I::I64Extend32S);
 
-        self.inst("i32.trunc_sat_f32_s", &[F32], I32, I::I32TruncSatF32S);
+        self.inst("i32.trunc_sat_f32_s", &[F32], Some(I32), I::I32TruncSatF32S);
-        self.inst("i32.trunc_sat_f32_u", &[F32], I32, I::I32TruncSatF32U);
+        self.inst("i32.trunc_sat_f32_u", &[F32], Some(I32), I::I32TruncSatF32U);
-        self.inst("i32.trunc_sat_f64_s", &[F64], I32, I::I32TruncSatF64S);
+        self.inst("i32.trunc_sat_f64_s", &[F64], Some(I32), I::I32TruncSatF64S);
-        self.inst("i32.trunc_sat_f64_u", &[F64], I32, I::I32TruncSatF64U);
+        self.inst("i32.trunc_sat_f64_u", &[F64], Some(I32), I::I32TruncSatF64U);
-        self.inst("i64.trunc_sat_f32_s", &[F32], I64, I::I64TruncSatF32S);
+        self.inst("i64.trunc_sat_f32_s", &[F32], Some(I64), I::I64TruncSatF32S);
-        self.inst("i64.trunc_sat_f32_u", &[F32], I64, I::I64TruncSatF32U);
+        self.inst("i64.trunc_sat_f32_u", &[F32], Some(I64), I::I64TruncSatF32U);
-        self.inst("i64.trunc_sat_f64_s", &[F64], I64, I::I64TruncSatF64S);
+        self.inst("i64.trunc_sat_f64_s", &[F64], Some(I64), I::I64TruncSatF64S);
-        self.inst("i64.trunc_sat_f64_u", &[F64], I64, I::I64TruncSatF64U);
+        self.inst("i64.trunc_sat_f64_u", &[F64], Some(I64), I::I64TruncSatF64U);
+
+        self.inst(
+            "memory.copy",
+            &[I32, I32, I32],
+            None,
+            I::MemoryCopy { src: 0, dst: 0 },
+        );
+        self.inst("memory.fill", &[I32, I32, I32], None, I::MemoryFill(0));
     }
 
-    fn inst(&mut self, name: &str, params: &[Type], ret: Type, ins: enc::Instruction<'static>) {
+    fn inst(
+        &mut self,
+        name: &str,
+        params: &[Type],
+        ret: Option<Type>,
+        ins: enc::Instruction<'static>,
+    ) {
         if let Some(slash_idx) = name.find('/') {
             self.insert(name[(slash_idx + 1)..].to_string(), params, ret, &ins);
             let mut full_name = name[..slash_idx].to_string();
@@ -130,7 +163,7 @@ impl Intrinsics {
         &mut self,
         name: String,
         params: &[Type],
-        ret: Type,
+        ret: Option<Type>,
         ins: &enc::Instruction<'static>,
     ) {
         self.0
@@ -157,7 +190,7 @@ impl Intrinsics {
             "i64.load32_u" => MemInstruction::new(I64, I::I64Load32_U, 2),
             "f32.load" => MemInstruction::new(F32, I::F32Load, 2),
             "f64.load" => MemInstruction::new(F64, I::F64Load, 3),
-            _ => return None
+            _ => return None,
         };
         return Some(ins);
     }
@@ -175,7 +208,7 @@ impl Intrinsics {
             "i64.store32" => MemInstruction::new(I64, I::I64Store32, 2),
             "f32.store" => MemInstruction::new(F32, I::F32Store, 2),
             "f64.store" => MemInstruction::new(F64, I::F64Store, 3),
-            _ => return None
+            _ => return None,
         };
         return Some(ins);
     }
@@ -184,13 +217,19 @@ impl Intrinsics {
 pub struct MemInstruction {
     pub type_: Type,
     pub instruction: fn(MemArg) -> enc::Instruction<'static>,
-    pub natural_alignment: u32
+    pub natural_alignment: u32,
 }
 
 impl MemInstruction {
-    fn new(type_: Type, instruction: fn(MemArg) -> enc::Instruction<'static>, natural_alignment: u32) -> MemInstruction {
+    fn new(
+        type_: Type,
+        instruction: fn(MemArg) -> enc::Instruction<'static>,
+        natural_alignment: u32,
+    ) -> MemInstruction {
         MemInstruction {
-            type_, instruction, natural_alignment
+            type_,
+            instruction,
+            natural_alignment,
         }
     }
 }

src/parser.rs

@@ -250,23 +250,23 @@ fn report_errors(errors: Vec<Simple<String, Span>>, sources: &Sources) {
 
 type LexerError = Simple<char, Span>;
 fn lexer() -> impl Parser<char, Vec<(Token, Span)>, Error = LexerError> {
-    let float64 = text::int(10)
+    let float64 = text::digits(10)
         .chain::<char, _, _>(just('.').chain(text::digits(10)))
         .then_ignore(just("f64"))
         .collect::<String>()
         .map(Token::Float64);
 
-    let float = text::int(10)
+    let float = text::digits(10)
         .chain::<char, _, _>(just('.').chain(text::digits(10)))
         .collect::<String>()
         .map(Token::Float);
 
     let integer = just::<_, _, LexerError>("0x")
-        .ignore_then(text::int(16))
+        .ignore_then(text::digits(16))
         .try_map(|n, span| {
             u64::from_str_radix(&n, 16).map_err(|err| LexerError::custom(span, err.to_string()))
         })
-        .or(text::int(10).try_map(|n: String, span: Span| {
+        .or(text::digits(10).try_map(|n: String, span: Span| {
             n.parse::<u64>()
                 .map_err(|err| LexerError::custom(span, err.to_string()))
         }))
@@ -324,16 +324,17 @@ fn lexer() -> impl Parser<char, Vec<(Token, Span)>, Error = LexerError> {
         just("<<"),
         just(">>"),
         just("#>>"),
-        just("#<"),
-        just("#>"),
         just(">="),
         just("<="),
         just("=="),
         just("!="),
         just("#>="),
         just("#<="),
+        just("#<"),
+        just("#>"),
         just("->"),
         just(":="),
+        just("<|"),
     ))
     .map(|s| s.to_string())
     .or(one_of("+-*/%&^|<=>").map(|s: char| s.to_string()))
@@ -376,17 +377,10 @@ fn lexer() -> impl Parser<char, Vec<(Token, Span)>, Error = LexerError> {
 
     let comment = single_line.or(multi_line);
 
-    let token = float
+    let token = choice((
-        .or(float64)
+        float, float64, int64, int_float, int, str_, char_, op, ctrl, ident,
-        .or(int64)
+    ))
-        .or(int_float)
+    .recover_with(skip_then_retry_until([]));
-        .or(int)
-        .or(str_)
-        .or(char_)
-        .or(op)
-        .or(ctrl)
-        .or(ident)
-        .recover_with(skip_then_retry_until([]));
 
     token
         .map_with_span(|tok, span| (tok, span))
@@ -522,6 +516,36 @@ fn script_parser() -> impl Parser<Token, ast::Script, Error = ScriptError> + Clo
                 })
                 .boxed();
 
+            let local_tee_op = identifier
+                .then(
+                    product_op
+                        .clone()
+                        .or(sum_op.clone())
+                        .or(shift_op.clone())
+                        .or(bit_op.clone()),
+                )
+                .then_ignore(just(Token::Op(":=".to_string())))
+                .then(expression.clone())
+                .map_with_span(|((name, op), expr), span| ast::Expr::LocalTee {
+                    name: name.clone(),
+                    value: Box::new(
+                        ast::Expr::BinOp {
+                            left: Box::new(
+                                ast::Expr::Variable {
+                                    name,
+                                    local_id: None,
+                                }
+                                .with_span(span.clone()),
+                            ),
+                            right: Box::new(expr),
+                            op,
+                        }
+                        .with_span(span),
+                    ),
+                    local_id: None,
+                })
+                .boxed();
+
             let loop_expr = just(Token::Loop)
                 .ignore_then(identifier)
                 .then(block.clone())
@@ -632,28 +656,31 @@ fn script_parser() -> impl Parser<Token, ast::Script, Error = ScriptError> + Clo
                     value: value.map(Box::new),
                 });
 
-            let atom = val
+            let atom = choice((
-                .or(function_call)
+                val,
-                .or(local_tee)
+                function_call,
-                .or(variable)
+                local_tee,
-                .or(block_expr)
+                local_tee_op,
-                .or(branch)
+                variable,
-                .or(branch_if)
+                block_expr,
-                .or(let_)
+                branch,
-                .or(select)
+                branch_if,
-                .or(return_)
+                let_,
-                .map_with_span(|expr, span| expr.with_span(span))
+                select,
-                .or(expression
+                return_,
-                    .clone()
+            ))
-                    .delimited_by(just(Token::Ctrl('(')), just(Token::Ctrl(')'))))
+            .map_with_span(|expr, span| expr.with_span(span))
-                .or(block)
+            .or(expression
-                .recover_with(nested_delimiters(
+                .clone()
-                    Token::Ctrl('('),
+                .delimited_by(just(Token::Ctrl('(')), just(Token::Ctrl(')'))))
-                    Token::Ctrl(')'),
+            .or(block)
-                    [(Token::Ctrl('{'), Token::Ctrl('}'))],
+            .recover_with(nested_delimiters(
-                    |span| ast::Expr::Error.with_span(span),
+                Token::Ctrl('('),
-                ))
+                Token::Ctrl(')'),
-                .boxed();
+                [(Token::Ctrl('{'), Token::Ctrl('}'))],
+                |span| ast::Expr::Error.with_span(span),
+            ))
+            .boxed();
 
             let unary_op = just(Token::Op("-".to_string()))
                 .to(ast::UnaryOp::Negate)