Last active
August 27, 2016 02:43
-
-
Save zkat/e7e9380ff050302de67813ef76258cc8 to your computer and use it in GitHub Desktop.
Sketched out example of protocol library built on top of genfun
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
var Protocol = require('genfun-protocol') | |
var Eq = Protocol(['a', 'b'], { | |
eql: ['a', 'b'], | |
// Extra set of [] and you can add a default implementation! | |
// This will dispatch only for existing instances | |
// (that is, it doesn't fall through to [Object, Object] in this case) | |
neq: [['a', 'b'], (a, b) => !Eq.eql(a, b)] | |
}) | |
Eq.impl([Number, Number], { | |
eql: [[Number, Number], (a, b) => a === b] | |
// neq [Number, Number] is automatically implemented | |
}) | |
var Show = Protocol(['a'], { | |
show: ['a'] | |
}) | |
class Thing {} | |
class Stream {} | |
Show.impl([Thing], { | |
out: [[Thing], (x) => JSON.stringify(x)] | |
}) | |
Show.impl([Stream], { | |
out: [[Stream], (stream) => { | |
var buffer = '' | |
stream.on('data', (chunk, enc, next) => { | |
buffer += chunk.toString(enc) | |
next() | |
}) | |
return new Promise((resolve, reject) => { | |
stream.on('end', () => resolve(buffer)) | |
stream.on('error', (e) => reject(e)) | |
}) | |
}] | |
}) | |
var Read = Protocol([Show('obj'), 'exemplar'], { | |
in: ['obj', 'exemplar'] | |
}) | |
Read.impl([String, Thing], { | |
in: [[String, Thing], (obj) => JSON.parse(Show.show(obj))] | |
}) | |
Read.impl([Stream, Thing], { | |
in: [[Stream, Thing], (stream) => { | |
return Show.show(stream).then(JSON.parse) | |
}] | |
}) | |
// Error, because Number doesn't have a Show impl | |
Read.impl([Number, Thing], { | |
in: [[Number, Thing], (num) => '' + num] | |
}) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment