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pegjs/lib/compiler/passes/report-infinite-repetition.js

40 lines
1012 B
JavaScript

"use strict";
// Reports expressions that don't consume any input inside |*| or |+| in the
// grammar, which prevents infinite loops in the generated parser.
function reportInfiniteRepetition( ast, session ) {
const check = session.buildVisitor( {
zero_or_more( node ) {
if ( ! ast.alwaysConsumesOnSuccess( node.expression ) ) {
session.error(
"Possible infinite loop when parsing (repetition used with an expression that may not consume any input).",
node.location
);
}
},
one_or_more( node ) {
if ( ! ast.alwaysConsumesOnSuccess( node.expression ) ) {
session.error(
"Possible infinite loop when parsing (repetition used with an expression that may not consume any input).",
node.location
);
}
}
} );
check( ast );
}
module.exports = reportInfiniteRepetition;