hodur-engine notes

Motivation

Awesome if you could generate stuff from a single source of definition

lacinia-schema

spec

datomic-schema

etc...

Especially if they can refer to the same datatype

e.g. would be expensive to ensure that the person definition in the lacinia schema is consistent with the corresponding spec

And if writing your own generator is easy

Predecessor(?)

Difference

Umlaut

DSL

parsed with instaparse

generators work with the resulting map

extend definition beyond dsl via annotation

Hudor

edn

read by the clojure reader

returning a datascript db

which generators can query

extend definition beyond default via metadata

Implementation details

Using a generator

No datascript/datalog knowledge required

add hudor/engine along with whatever plugins that you will use as deps. Here I will stick to spec.

code:clojure

{:deps {hodur/engine {:mvn/version "0.1.5"}

hodur/spec-schema {:mvn/version "0.1.0"}}}

Define a model in edn along with meta data that is recognized by the generator

code:clojure

[^{:spec/tag-recursive true}

Food

[^{:type String

ingredients]

^{:spec/tag-recursive true}

Diet

[^{:type Food

:nullable true}

meals]]

Invoke the generator

code:clojure

(hodur-spec/schema

(hodur/init-path "domain-model.edn")

{:prefix "foo"})

=>

[(clojure.spec.alpha/def

:foo.food/ingredients

(clojure.spec.alpha/coll-of

clojure.core/string?

:min-count

0

:max-count

4))

(clojure.spec.alpha/def

:foo/food

(clojure.spec.alpha/keys

:req-un

:opt-un

[]))

(clojure.spec.alpha/def

:foo.diet/meals

(clojure.spec.alpha/coll-of :foo/food :min-count 1 :max-count 3))

(clojure.spec.alpha/def

:foo/diet

Authoring a generator

query the datascript db and do stuff