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Issue 473 assertion #476

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Issue 473 assertion #476

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4f9930a
Switch if/else condition to assert
ratmice Dec 3, 2024
9769c4b
Add `ast::Symbol` variant for %empty productions.
ratmice Dec 3, 2024
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12 changes: 12 additions & 0 deletions cfgrammar/src/lib/yacc/ast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,7 @@ pub struct Production {
pub enum Symbol {
Rule(String, Span),
Token(String, Span),
Empty(Span),
}

/// Specifies an index into a `GrammarAst.tokens` or a `GrammarAST.rules`.
Expand Down Expand Up @@ -133,6 +134,7 @@ impl fmt::Display for Symbol {
match *self {
Symbol::Rule(ref s, _) => write!(f, "{}", s),
Symbol::Token(ref s, _) => write!(f, "{}", s),
Symbol::Empty(_) => write!(f, "%empty"),
}
}
}
Expand Down Expand Up @@ -262,6 +264,7 @@ impl GrammarAST {
});
}
}
Symbol::Empty(_) => {}
}
}
}
Expand Down Expand Up @@ -300,6 +303,7 @@ impl GrammarAST {
});
}
}
Symbol::Empty(_) => {}
}
}
Ok(())
Expand All @@ -311,6 +315,9 @@ impl GrammarAST {
let (kind, span) = match symidx.symbol(self) {
Symbol::Rule(_, span) => (YaccGrammarWarningKind::UnusedRule, span),
Symbol::Token(_, span) => (YaccGrammarWarningKind::UnusedToken, span),
Symbol::Empty(_) => {
unreachable!()
}
};
YaccGrammarWarning {
kind,
Expand Down Expand Up @@ -340,6 +347,9 @@ impl GrammarAST {
Symbol::Token(sym_name, _) => {
expected_unused_tokens.insert(sym_name);
}
Symbol::Empty(_) => {
unreachable!();
}
}
}
if let Some(implicit_tokens) = self.implicit_tokens.as_ref() {
Expand All @@ -364,6 +374,8 @@ impl GrammarAST {
Symbol::Token(name, _) => {
seen_tokens.insert(name);
}
Symbol::Empty(_) => {
}
};
}
}
Expand Down
1 change: 1 addition & 0 deletions cfgrammar/src/lib/yacc/grammar.rs
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Expand Up @@ -295,6 +295,7 @@ where
prod.push(Symbol::Rule(rule_map[implicit_rule]));
}
}
ast::Symbol::Empty(_) => {}
};
}
let mut prec = None;
Expand Down
28 changes: 18 additions & 10 deletions cfgrammar/src/lib/yacc/parser.rs
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Expand Up @@ -660,13 +660,19 @@ impl YaccParser {
i = self.parse_ws(i, true)?;
while i < self.src.len() {
if let Some(j) = self.lookahead_is("|", i) {
if syms.is_empty() {
syms.push(Symbol::Empty(Span::new(i, i)));
}
self.ast.add_prod(rn.clone(), syms, prec, action);
syms = Vec::new();
prec = None;
action = None;
i = self.parse_ws(j, true)?;
continue;
} else if let Some(j) = self.lookahead_is(";", i) {
if syms.is_empty() {
syms.push(Symbol::Empty(Span::new(i, i)));
}
self.ast.add_prod(rn, syms, prec, action);
return Ok(j);
}
Expand Down Expand Up @@ -694,19 +700,20 @@ impl YaccParser {
if !(self.lookahead_is("|", i).is_some() || self.lookahead_is(";", i).is_some()) {
return Err(self.mk_error(YaccGrammarErrorKind::ProductionNotTerminated, i));
}
} else if let Some(mut j) = self.lookahead_is("%empty", i) {
j = self.parse_ws(j, true)?;
} else if let Some(j) = self.lookahead_is("%empty", i) {
let k = self.parse_ws(j, true)?;
// %empty could be followed by all sorts of weird syntax errors: all we try and do
// is say "does this production look like it's finished" and trust that the other
// errors will be caught by other parts of the parser.
if !syms.is_empty()
| !(self.lookahead_is("|", j).is_some()
|| self.lookahead_is(";", j).is_some()
|| self.lookahead_is("{", j).is_some())
| !(self.lookahead_is("|", k).is_some()
|| self.lookahead_is(";", k).is_some()
|| self.lookahead_is("{", k).is_some())
{
return Err(self.mk_error(YaccGrammarErrorKind::NonEmptyProduction, i));
}
i = j;
syms.push(Symbol::Empty(Span::new(i, j)));
i = k;
} else {
let (j, sym, span) = self.parse_token(i)?;
if self.ast.tokens.contains(&sym) {
Expand Down Expand Up @@ -1238,7 +1245,7 @@ mod test {
assert_eq!(
grm.prods[grm.get_rule("A").unwrap().pidxs[0]],
Production {
symbols: vec![],
symbols: vec![Symbol::Empty(Span::new(32, 32))],
precedence: None,
action: None
}
Expand All @@ -1257,7 +1264,7 @@ mod test {
assert_eq!(
grm.prods[grm.get_rule("B").unwrap().pidxs[1]],
Production {
symbols: vec![],
symbols: vec![Symbol::Empty(Span::new(56, 56))],
precedence: None,
action: None
}
Expand All @@ -1266,7 +1273,7 @@ mod test {
assert_eq!(
grm.prods[grm.get_rule("C").unwrap().pidxs[0]],
Production {
symbols: vec![],
symbols: vec![Symbol::Empty(Span::new(74, 74))],
precedence: None,
action: None
}
Expand Down Expand Up @@ -2396,14 +2403,15 @@ Expr -> () : D;
for sym in &ast.prods[*pidx].symbols {
let name = match sym {
Symbol::Token(name, _) | Symbol::Rule(name, _) => name.clone(),
Symbol::Empty(_) => "%empty".to_string(),
};
prod_names.insert(name);
}
}
assert_eq!(ast.prods.len(), 5);
assert_eq!(
prod_names,
HashSet::from_iter(["A", "B", "C", "D"].map(|s| s.to_owned()))
HashSet::from_iter(["A", "B", "C", "D", "%empty"].map(|s| s.to_owned()))
);
}

Expand Down
2 changes: 2 additions & 0 deletions lrtable/src/lib/statetable.rs
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Expand Up @@ -1041,6 +1041,7 @@ S: S | ;";
match sym {
ast::Symbol::Rule(_, span) => assert_eq!(span, &Span::new(6, 7)),
ast::Symbol::Token(_, _) => panic!("Incorrect symbol"),
ast::Symbol::Empty(_) => panic!("Empty symbol"),
}
}
Err(e) => panic!("Incorrect error returned {:?}", e),
Expand Down Expand Up @@ -1072,6 +1073,7 @@ T: S | ;";
match sym {
ast::Symbol::Rule(_, span) => assert_eq!(span, &Span::new(15, 16)),
ast::Symbol::Token(_, _) => panic!("Incorrect symbol"),
ast::Symbol::Empty(_) => panic!("Empty symbol"),
}
}
Err(e) => panic!("Incorrect error returned {:?}", e),
Expand Down
23 changes: 11 additions & 12 deletions nimbleparse/src/diagnostics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -24,18 +24,17 @@ where
usize: num_traits::AsPrimitive<StorageT>,
StorageT: 'static + num_traits::PrimInt + num_traits::Unsigned,
{
if usize::from(pidx) < ast.prods.len() {
let prod = &ast.prods[usize::from(pidx)];
prod.symbols
.iter()
.map(|sym| match sym {
Symbol::Rule(name, span) => (format!("'{}'", name), span),
Symbol::Token(name, span) => (format!("'{}'", name), span),
})
.unzip()
} else {
(vec![], vec![])
}
let pidx = usize::from(pidx);
assert!(pidx < ast.prods.len());
let prod = &ast.prods[pidx];
prod.symbols
.iter()
.map(|sym| match sym {
Symbol::Rule(name, span) => (format!("'{}'", name), span),
Symbol::Token(name, span) => (format!("'{}'", name), span),
Symbol::Empty(span) => (format!("%empty"), span),
})
.unzip()
}

impl<'a> SpannedDiagnosticFormatter<'a> {
Expand Down
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