cscalfani

Type Safe JSON Decoding in Elm

The power of a Static Typed language can seem magical at first. But the goal here is to take a tiny peak behind that curtain.

Elm's implementation of JSON parsing is type safe and how it achieves that can seem like a mystery. Even though I got the code to work, it took me a while to fully understand how it works.

I'm writing it down here for 2 reasons. To help others gain a greater understanding of Types and so I don't forget what I learned.

Word of Caution

henridf

I needed to quickly encode a protobuf from the command-line, and while I pretty much immediately came across protoc --encode as the obvious solution, I did not find much documentation on the input textual syntax.

Here is the relevant snippet from protoc --help:

--encode=MESSAGE_TYPE       Read a text-format message of the given type
                              from standard input and write it in binary
                              to standard output.  The message type must
                              be defined in PROTO_FILES or their imports.