Maximum Call Stack Size Exceeded while parsing custom grammar

[fabianfreyer]

Parsing the following grammar:

RValue ::= Number | InfixExpression
InfixExpression ::= RValue InfixOperator RValue
InfixOperator ::= "+" | "-" | "*" | "/"
Number ::= "-"? ("0" | [1-9] [0-9]*) ("." [0-9]+)? (("e" | "E") ( "-" | "+" )? ("0" | [1-9] [0-9]*))?

Fails with the following error message:

/home/user/service-xsharp/service/node_modules/ebnf/dist/Parser.js:53
        name: name.replace(decorationRE, '').replace(preDecorationRE, ''),
                   ^

RangeError: Maximum call stack size exceeded
    at String.replace (<anonymous>)
    at parseRuleName (/home/user/service-xsharp/service/node_modules/ebnf/dist/Parser.js:53:20)
    at options.forEach.phases (/home/user/service-xsharp/service/node_modules/ebnf/dist/Parser.js:256:47)
    at Array.forEach (<anonymous>)
    at Parser.parse (/home/user/service-xsharp/service/node_modules/ebnf/dist/Parser.js:233:25)
    at options.forEach.phases (/home/user/service-xsharp/service/node_modules/ebnf/dist/Parser.js:282:51)
    at Array.forEach (<anonymous>)
    at Parser.parse (/home/user/service-xsharp/service/node_modules/ebnf/dist/Parser.js:233:25)
    at options.forEach.phases (/home/user/service-xsharp/service/node_modules/ebnf/dist/Parser.js:282:51)
    at Array.forEach (<anonymous>)

[menduz]

In this case we have an invalid state machine for the parser, but the error isn't happy at all.

RValue -> InfixExpression -> RValue -> InfixExpression -> RValue -> InfixExpression ...

That is called left recursion in parsers, and this generator doesn't support it.

Though, you can reconfigure your grammar:

{ ws=explicit }

InfixExpression ::= RValue (InfixOperator RValue)* {simplifyWhenOneChildren=true}
RValue ::= Number WS*
InfixOperator ::= WS* ("+" | "-" | "*" | "/") WS*
Number ::= "-"? ("0" | [1-9] [0-9]*) ("." [0-9]+)? (("e" | "E") ( "-" | "+" )? ("0" | [1-9] [0-9]*))?

WS ::= ' '