0a312b4f40
This is a well-worn idea: use a `promise-channel` of `[result nil]` or
`[nil error]` pairs. The `go-pair` and `<?` macros handle catching
exceptions (important, given that synchronous CLJ code expects to throw
rather than return an error promise or similar), allowing code like:
```
(go-pair
(let [result (<? (pair-chan-fn))]
(when (not result)
(throw (Exception. "No result!")))
(transform result)))
```
to be expressed naturally. These are the equivalents of `async` and
`await` in JS.
The implementation is complicated by significant incompatibilities
between CLJ and CLJS. The solution presented here takes care to
separate the macro definitions into CLJ. Sadly, this requires
namespacing the per-environment symbols explicitly; but we hope to
minimize such code in files like this.
The most significant restriction to this approach is that consumers must
require the transitive dependencies of the macro-defining modules. See
the included tests (both CLJ and CLJS) for the appropriate
incantations (for pair-chan, core.async, and test).
17 lines
551 B
Clojure
17 lines
551 B
Clojure
;; This Source Code Form is subject to the terms of the Mozilla Public
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;; License, v. 2.0. If a copy of the MPL was not distributed with this
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;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
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(ns datomish.test-macros-test
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(:require-macros
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[datomish.pair-chan :refer [go-pair]]
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[datomish.test-macros :refer [deftest-async]]
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[cljs.core.async.macros])
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(:require [cljs.core.async]
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[cljs.test :refer-macros [is are deftest testing async]]))
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(deftest sync-test
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(is (= 1 1)))
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(deftest-async async-test
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(is (= 1 1)))
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