deprecate _capt and _expr

[twada]

_capt and _expr is now out of date in the destructuring era.
Seeking for a better way without them.

see: allow destructuring of t parameter. by jamestalmage · Pull Request #302 · sindresorhus/ava

[twada]

rough design

import assert from 'power-assert';
import _powerAssertCapture from 'power-assert-capturing';

assert(_powerAssertCapture(this, function (_capt) {
    return _capt(falsyStr, 'arguments/0');
}, {
    content: 'assert(falsyStr)',
    filepath: 'test/fixtures/Identifier/fixture.js',
    line: 3
}));

[jamestalmage]

race condition: power-assert-js/empower#21 (comment)

While yours looks better, it won't work with async/await:

async function foo() {
   function bar() {
     // await will not work in here.
   }
}

We could do

assert(await _powerAssertCapture(this, ...))

But then you end up having to change how you do things in generators vs async functions vs synchronous functions.

[twada]

closed since Embed value capturing helper into transpiled code has landed