#748 Fix signed numbers not parsing correctly after parens (#749)

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project does not currently adhere to a particular versioning scheme.
 
 ### Fixed
 - Fix type checker not properly unifying all the arms of a match expression. ([#734][gh-734])
+- Fix signed numbers (i24 and f24) not being parsed after parenthesis `(`. ([#748][gh-748])
 
 ## [0.2.37] - 2024-10-18
 
@@ -443,3 +444,4 @@ and this project does not currently adhere to a particular versioning scheme.
 [gh-706]: https://github.com/HigherOrderCO/Bend/issues/706
 [gh-734]: https://github.com/HigherOrderCO/Bend/issues/734
 [gh-736]: https://github.com/HigherOrderCO/Bend/issues/736
+[gh-748]: https://github.com/HigherOrderCO/Bend/issues/748

src/fun/parser.rs

@@ -590,21 +590,55 @@ impl<'a> FunParser<'a> {
       // App, Tup, Num Op
       if self.starts_with("(") {
         self.advance_one();
-
-        // Opr but maybe a tup
         self.skip_trivia();
+
+        // Opr but maybe something else
+        // ( +/-n ,    -> Tup with Int/Float
+        // ( +/-n )    -> Int/Float
+        // ( +/-n term -> App with Int/Float
+        // ( * ,       -> Tup with Era
+        // ( * )       -> Era
+        // ( opr       -> Num Op
         if let Some(opr) = self.try_parse_oper() {
+          if (opr == Op::ADD || opr == Op::SUB) && self.peek_one().is_some_and(|c| "0123456789".contains(c)) {
+            unexpected_tag(self)?;
+            *self.index() -= 1;
+            let num = self.parse_number()?;
+            let head = Term::Num { val: num };
+            self.skip_trivia();
+
+            if self.starts_with(",") {
+              self.consume_exactly(",")?;
+              let tail = self.list_like(|p| p.parse_term(), "", ")", ",", true, 1)?;
+              let els = [head].into_iter().chain(tail).collect();
+              return Ok(Term::Fan { fan: FanKind::Tup, tag: tag.unwrap_or(Tag::Static), els });
+            }
+
+            if self.starts_with(")") {
+              self.consume_exactly(")")?;
+              return Ok(head);
+            }
+
+            let els = self.list_like(|p| p.parse_term(), "", ")", "", false, 0)?;
+            let term = els.into_iter().fold(head, |fun, arg| Term::App {
+              tag: tag.clone().unwrap_or(Tag::Static),
+              fun: Box::new(fun),
+              arg: Box::new(arg),
+            });
+            return Ok(term);
+          }
+
           self.skip_trivia();
 
-          // jk, actually a tuple
-          if self.starts_with(",") && opr == Op::MUL {
+          if opr == Op::MUL && self.starts_with(",") {
             self.consume_exactly(",")?;
             let tail = self.list_like(|p| p.parse_term(), "", ")", ",", true, 1)?;
             let els = [Term::Era].into_iter().chain(tail).collect();
             return Ok(Term::Fan { fan: FanKind::Tup, tag: tag.unwrap_or(Tag::Static), els });
           }
 
-          if opr == Op::MUL && self.try_consume(")") {
+          if opr == Op::MUL && self.starts_with(")") {
+            self.consume_exactly(")")?;
             return Ok(Term::Era);
           }
 

tests/golden_tests/parse_file/tup_with_signed.bend

@@ -0,0 +1,9 @@
+# Test that we can parse tuples and apps beginning with signed numbers
+main = 
+  let a = (+1, +1)
+  let b = (+1.1324)
+  let c = (-6.234, -1)
+  let d = (-1)
+  let e = (+6 * λx x)
+  let f = ((*) λx x)
+  (+ a (+ b (+ c (+ d (- e f)))))

tests/snapshots/parse_file__tup_with_signed.bend.snap

@@ -0,0 +1,6 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/parse_file/tup_with_signed.bend
+---
+unchecked main: Any
+(main) = let a = (+1, +1); let b = 1.132; let c = (-6.234, -1); let d = -1; let e = (+6 * λx x); let f = (* λx x); (+ a (+ b (+ c (+ d (- e f)))))