find-the-block.js

// block-lambda proponents: what does this program do?

function omgnomakeitstopkillitwithfire (t) {
  x = {|y|
    return "returning: " + y
  }

  // now here comes a bunch of code.
  // imagine there are 50 lines here

  t(x)

  // now a bunch more stuff.
  // eventually:

  x("there")

  // then a bunch more stuff
  // ending with:

  return 100
}

var ret = omgnomakeitstopkillitwithfire(function (cb) {
  alert("before")
  cb("here")
  alert("after")
})

alert(ret)

/**
 * HOW DOES THIS NOT QUALIFY AS INSANE ACTION-AT-A-DISTANCE???
 * Seriously, this belongs in the bad-parts bucket with `with` and `eval`.
 **/

@grncdr: stretch your imagination with some Smalltalk-80 code. There are plenty of uses for mixed local and non-local returns. See https://github.com/allenwb/ESnext-experiments/blob/master/ST80collections-exp0-blp.js for a start.

/be

@BrendanEich, much better example of used mixed returns, I retract my previous suggestion.