A tool to convert from EDN to JSON.
$ ej < some.edn > some.json
Note: no command line options (or even filenames) are (currently) accepted.
Output is one record per line.
$ cat drinks.edn
{:name "milkshake" :sizes [330 500 1000] :contents {:milk true :alcohol false}}
{:name "latte" :sizes [125 250] :contents {:milk true :alcohol false}}
{:name "beer" :sizes [284 568] :contents {:milk false :alcohol true}}
{:name "white russian" :sizes [100] :contents {:milk true :alcohol true}}
{:name "water" :sizes [1000] :contents {:milk false :alcohol false}}
$ ej < drinks.edn
{"contents":{"alcohol":false,"milk":true},"name":"milkshake","sizes":[330,500,1000]}
{"contents":{"alcohol":false,"milk":true},"name":"latte","sizes":[125,250]}
{"contents":{"alcohol":true,"milk":false},"name":"beer","sizes":[284,568]}
{"contents":{"alcohol":true,"milk":true},"name":"white russian","sizes":[100]}
{"contents":{"alcohol":false,"milk":false},"name":"water","sizes":[1000]}
ej works well with jq, a tool for command-line JSON processing.
To get pretty JSON from EDN:
$ ej < some.edn | jq .
To query EDN from the command line:
$ cat drinks.edn | ej | jq -r 'select(.contents.milk) | .name'
milkshake
latte
white russian
- EDN tagging information is removed
- Rational numbers are parsed, and become floats in JSON (the EDN spec doesn't mention rationals, but it looks as if it should)
- keywords and symbols as map keys become strings
- other types used as map keys become JSON-encoded strings
-
The Haskell Stack
$ curl -sSL https://get.haskellstack.org/ | sh
(Be prepared for a wait)
$ git clone https://github.com/uswitch/ej.git
$ cd ej
$ stack setup
$ stack install
which, if all goes well, will create ~/.local/bin/ej. It may be a
good idea to put ~/.local/bin in your PATH.
- Needed a fast way to convert streams of EDN to JSON, to get benefit of tools such as jq.
- Clojure takes too long to start for a command line tool.
- There's a Go implementation, but its licence is unclear.
- I'm a Haskell beginner, so I thought this would make a good first (useful) project.