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parsingjavacc

Why this gives Token Manager Exception

I am using Lexical state in JavaCC parser to switch from one state to other, after it matches Token A1.

< DEFAULT > TOKEN :
{
    <A1 : "Hello"> : STATE2
    | <A2 : "World">
}

< STATE2 > TOKEN :
{
    <B1: "World"> : DEFAULT
}

When I try to parse Hello Wolrd, It throws Token Manager Error.

Solution

  • Because in STATE2 there is no rule to match any prefix of " Wolrd". In case you meant "Hello World", it is because there is no rule in STATE2 to match any prefix of " World".

    If you want to ignore spaces, add a rule

    <DEFAULT, STATE2> SKIP : { " " }