https://github.com/athos/specium
Inverse of s/form, reducing eval calls as much as possible
https://github.com/athos/specium
clojure clojure-spec clojurescript spec
Last synced: 3 months ago
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Inverse of s/form, reducing eval calls as much as possible
- Host: GitHub
- URL: https://github.com/athos/specium
- Owner: athos
- License: epl-1.0
- Created: 2017-07-06T04:20:59.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2017-12-10T11:27:05.000Z (over 7 years ago)
- Last Synced: 2025-02-14T07:51:19.912Z (3 months ago)
- Topics: clojure, clojure-spec, clojurescript, spec
- Language: Clojure
- Size: 28.3 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# specium
[](https://clojars.org/specium)
[](https://circleci.com/gh/athos/specium/tree/master)
[](https://codecov.io/gh/athos/specium)
Specium provides the inverse function of `clojure.spec(.alpha)/form`, reducing `eval` calls as much as possible.
## Installation
Add the following to your `:dependencies`:
[](http://clojars.org/specium)
## Usage
A common way of getting a `s/form`ed spec form back into a spec object is to call `eval` with it:
```clj
=> (s/form (s/map-of keyword? integer?))
(clojure.spec.alpha/map-of clojure.core/keyword? clojure.core/integer?)
=> (eval *1)
#object[clojure.spec.alpha$every_impl$reify__946 0x6d47d0b2 "clojure.spec.alpha$every_impl$reify__946@6d47d0b2"]
=> (s/conform *1 {:key "wrong value"})
:clojure.spec.alpha/invalid
=> (s/explain *2 {:key "wrong value"})
In: [:key 1] val: "wrong value" fails at: [1] predicate: integer?
:clojure.spec.alpha/spec #object[clojure.spec.alpha$every_impl$reify__946 0x6d47d0b2 "clojure.spec.alpha$every_impl$reify__946@6d47d0b2"]
:clojure.spec.alpha/value {:key "wrong value"}
nil
=>
```
Though it perfectly works, in some cases you might not be able to overlook `eval`'s inefficiency (eg. where lots of spec forms have to be dealt with).
_Specium_ provides the `->spec` fn, which can be used as the inverse function of `s/form`; that is, you can use it to get spec forms back to spec objects efficiently, almost without calling `eval`:
```clj
=> (require '[specium.core :as specium])
nil
=> (s/form (s/map-of keyword? integer?))
(clojure.spec.alpha/map-of clojure.core/keyword? clojure.core/integer?)
=> (def s (specium/->spec *1))
#'user/s
=> (s/conform s {:key "wrong value"})
:clojure.spec.alpha/invalid
=> (s/explain s {:key "wrong value"})
In: [:key 1] val: "wrong value" fails at: [1] predicate: integer?
:clojure.spec.alpha/spec #object[clojure.spec.alpha$every_impl$reify__946 0x581fa0b "clojure.spec.alpha$every_impl$reify__946@581fa0b"]
:clojure.spec.alpha/value {:key "wrong value"}
nil
=>
```
Note that we said "**almost** without calling `eval`", which means that `eval` is actually necessary in some cases, especially in the case the spec form has an `fn` form in it as a predicate.
## License
Copyright © 2017 Shogo Ohta
Distributed under the Eclipse Public License either version 1.0 or (at
your option) any later version.