optional

fun <T> EvalPE<T>.optional(): EvalPE<Option<T>>

Optional parsing expression that yields Some value of the type T on successful parsing, or None otherwise.

Samples

import io.kpeg.pe.Symbol.Rule
fun main() { 
   //sampleStart 
   // a - OK   - Some('a')
// A - FAIL - None
// b - FAIL - None

char('a')       // EvalPE<Char>
    .optional() // EvalPE<Option<Char>> 
   //sampleEnd
}

Sources

JVM source