parens, squareBrackets, braces, envelopes, bananas are not actually lazy when parsing an input string

[changlinli]

All the derived specializations of bracket aren't actually lazy in their argument when the generated parser is finally applied to some string. This prevents me from writing mutually recursive parsers that make use of any of these specializations of bracket as they will promptly enter an infinite loop when asked to parse any string.

import atto._
import Atto._

def dummyParser: Parser[Char] = {println("activate!"); char('a')}

// Prints activate!
parens(dummyParser).parseOnly("notparentheses")

def myParens[A](p: => Parser[A]): Parser[A] =
  bracket(char('('), p, char(')')) // Notice the absence of named

// Does not print anything
myParens(dummyParser).parseOnly("notparentheses")

[tpolecat]

Thanks, I'll have a look. This is a port of a lazy library and there are strictness issues buried here and there.

[changlinli]

FWIW I'm pretty sure the evaluation here is "accidental" in the sense that what's being forced is ultimately the toString method rather than the parsing itself.

[tpolecat]

Yep yep.