add a recursion limit to parser

src/parse.rs

@@ -26,6 +26,7 @@ pub enum ParseError {
  SplitInModifier,
  UnsplitInModifier,
  LineTooLong(usize),
+ RecursionLimit,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -100,6 +101,7 @@ impl fmt::Display for ParseError {
  "Split line into multiple lines (heuristic: {}/{}) 😏",
  width, ERROR_MAX_WIDTH
  ),
+ ParseError::RecursionLimit => write!(f, "Parsing recursion limit reached"),
  }
  }
 }
@@ -197,6 +199,7 @@ pub fn parse(
  errors,
  diagnostics,
  next_output_comment: 0,
+ depth: 0,
  };
  let items = parser.items(true);
  if parser.errors.is_empty() && parser.index < parser.tokens.len() {
@@ -207,7 +210,15 @@ pub fn parse(
  .map(ParseError::Unexpected),
  );
  }
- (items, parser.errors, parser.diagnostics)
+ let mut errors = parser.errors;
+ if let Some(error) = errors
+ .iter()
+ .find(|e| matches!(e.value, ParseError::RecursionLimit))
+ {
+ let error = error.clone();
+ errors = vec![error];
+ }
+ (items, errors, parser.diagnostics)
  }
  parse(input, inputs, tokens, lex_errors, src)
 }
@@ -220,6 +231,7 @@ struct Parser<'i> {
  next_output_comment: usize,
  errors: Vec<Sp<ParseError>>,
  diagnostics: Vec<Diagnostic>,
+ depth: usize,
 }
 
 type FunctionContents = (Option<Sp<Signature>>, Vec<Vec<Sp<Word>>>, Option<CodeSpan>);
@@ -732,6 +744,11 @@ impl<'i> Parser<'i> {
  Some(span.sp(make(items)))
  }
  fn try_modified(&mut self) -> Option<Sp<Word>> {
+ if self.depth > 50 {
+ self.errors
+ .push(self.prev_span().sp(ParseError::RecursionLimit));
+ return None;
+ }
  let (modifier, mod_span) = if let Some(prim) = Primitive::all()
  .filter(|prim| prim.is_modifier())
  .find_map(|prim| {
@@ -756,6 +773,7 @@ impl<'i> Parser<'i> {
  };
  let mut args = Vec::new();
  self.try_spaces();
+ self.depth += 1;
  for i in 0..modifier.args() {
  loop {
  args.extend(self.try_spaces());
@@ -782,6 +800,7 @@ impl<'i> Parser<'i> {
  break;
  }
  }
+ self.depth -= 1;
 
  let span = if let Some(last) = args.last() {
  mod_span.clone().merge(last.span.clone())

todo.md

@@ -1,6 +1,7 @@
 # Uiua Todo
 
 - 0.12
+ - Don't generate inlay hints if not necessary
  - `setinv` on and by inverses
  - Document on and by inverses
  - Pervasive switch functions and `repeat`