This is a kind of ad-hocish response to an interesting problem. In previous Syndicates, assertion changes were gathered into *patches* which *netted out* intra-turn changes. In this implementation, each change is relayed unchanged, so there is *no netting* going on. The closest we get is a convention that when things are being replaced, incoming assertions should be made before outgoing ones are retracted, so that the kind of glitch that's seen is a double-up of records, rather than a brief window where no records are present. So here, by moving the stop continuation into an onStop for the stopping facet (that nonetheless *executes* in that facet's parent's context), we allow the following pattern to run without problem glitching: react { assert Something(1); stop on asserted Condition() => react { assert Something(2); } } Observers like this... during Something(_) => { // **A** ... during Something($specific) => { // **B** } } will see + Something(1) + Something(2) - Something(1) rather than what they saw before this change, + Something(1) - Something(1) + Something(2) The consequence is that the line marked **A** above will *remain active* after this change, with the facet at **B** being replaced, rather than briefly tearing down the **A** facet when `- Something(1)` and then creating a fresh one when `+ Something(2)`. This came up in flappy bird, where I had react { at mainDs { assert ui.html('#board-area', template`<h1 class="score">${score.value}</h1>`); } at gameDs { stop on asserted GameOver() => react { at mainDs { assert ui.html( '#board-area', template`<h1 class="score">${score.value}<br/>GAME OVER</h1>`); } } } } which, in combination with the particular implementation of index.ts in the html package, caused the UIFragment responder to get confused and to not show the GAME OVER message - the previous score message was removed, but the new one wasn't manifested in the DOM. Changing the last `ui.html` above to `ui.context('foo').html` caused the problem to go away (by making it effectively two unrelated fragments, rather than a replacement of the content of a single fragment). |
||
---|---|---|
.. | ||
examples | ||
protocols | ||
src | ||
stubs | ||
test | ||
LICENCE | ||
Makefile | ||
README.md | ||
jest.config.ts | ||
package.json | ||
rollup.config.js | ||
tsconfig.json |
README.md
@syndicate-lang/core
An implementation of the Dataspace model that underpins the Syndicate language design.
Licence
@syndicate-lang/core, an implementation of Syndicate dataspaces for JS.
Copyright (C) 2016-2021 Tony Garnock-Jones tonyg@leastfixedpoint.com
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.