retroforth/example/json.retro

This is a wrapper over `jq` (https://stedolan.github.io/jq/) to
provide some access to JSON using RETRO.

~~~
{{
  :input   swap '/tmp/r.json file:spew ; 
  :command 'cat_/tmp/r.json_|_jq_'%s'_>/tmp/r.json2 s:format ;
  :process unix:system here '/tmp/r.json2 file:slurp ;
  :results '/tmp/r.json '/tmp/r.json2 &file:delete bi@ here ;
---reveal---
  :jq (ss-s) input command process results ;
}}
~~~

With this, I can begin to parse JSON and do things with it.

Import a JSON test set (`https://api.github.com/repos/stedolan/jq/commits?per_page=5`)

~~~
'JSON d:create
  here 'test.json file:slurp here s:length n:inc !Heap
~~~

Extract the commit messages using `jq`.

~~~
JSON '.[]_|_{message:_.commit.message}_|_flatten jq s:temp
~~~

This leaves output like:

    [
      "Improve jv_is_integer()"
    ]
    [
      "Dockerfile: Change base image to Debian Stable"
    ]

I can tokenize this and filter out the [ ] pairs:

~~~
ASCII:LF s:tokenize [ fetch [ $[ eq? ] [ $] eq? ] bi or not ] a:filter
~~~

And then display the resulting lines:

~~~
[ s:put nl ] a:for-each
~~~