== msgpack
[[toc:]]
An implementation of [[http://msgpack.org/|MessagePack]] for [[https://www.call-cc.org/|CHICKEN scheme v5]].

Forked from [[http://github.com/hugoArregui/msgpack-scheme|msgpack-scheme]] and partially rewritten
(ported to CHICKEN 5 and cleaned up).
I kept the original license and most of the original API. However the byte-blob have been replaced with
Chicken 5 native blob.
I removed the dependency on bind egg and the need for C++ code using built-ins features of C5.


=== Authors
Hugo Arregui: Original author of the egg.
Théo Cavignac: ported the egg to Chicken 5


=== Repository
Find the code at [[https://github.com/Lattay/chicken-msgpack|github.com]].


=== Requirements
This package requires the following eggs:
- matchable
- srfi-1
- srfi-69


=== Installation
Through {{Chicken egg repository}}:
Run {{chicken-install -s msgpack}} anywhere.

From source:
First install the required eggs listed above.
Then clone this [[https://github.com/Lattay/chicken-msgpack|repository]].
Finally run {{chicken-install -s}} in the root of this repository.


=== API Specification
Primitive pack-family procedures:

<enscript highlight="scheme"> 
(pack-uint port value)     ; will produce an error if the input is negative
(pack-sint port value)
(pack-float port FLONUM)   ; pack 32b floats, support both exact and inexact but convert to flonum (inexact) anyway
(pack-double port FLONUM)  ; pack 64b floats, same limitations as above
(pack-bin port BLOB)       ; chicken.blob byte blob
(pack-str port STRING)     ; string
(pack-array port VECTOR)   ; scheme vector, also support lists
(pack-map port HASH-TABLE) ; srfi-69 hash-table
(pack-ext port EXT)        ; extension (see below)
</enscript>

Also the simplest way to use is to use the generic procedures:

<enscript highlight="scheme"> 
(pack port value)
(pack/blob value)
</enscript>

These procedures will call primitive type packers, with the following rules:
- if the value has a packer, apply it.
- if the value is a string, it will be packed as str.
- if the value is a blob, it will be packed as bin.
- if the value is a char, it will be packed as a uint.
- if the value is a list, it will be packed as an array.
- if the value is a extension (see below), it will be packed as an ext

The {{/blob}} version return a blob of packed data, the others directly write it to the port.

Unpack procedures:
    [lang:scheme]

 (unpack port [mapper])
 (unpack/blob blob [mapper])

The optional mapper argument is applied to the output before returning.
The {{/blob}} version unpack the content of blob instead of reading from a port.


=== Extension
Extension is a record defined as:

{{
(define-record extension type data)
}}

* type: integer from 0 to 127
* data: a blob

Example:

<enscript highlight="scheme"> 
(make-extension 10 (string->byte-blob "hi"))
</enscript>


=== License
Distributed under the New BSD License.


=== History
v1.0.3 Ironing details for publication.

v1.0.0 Port to Chicken 5.
Breaking changes:
All blob related APIs have been changed to support Chicken native blob type.

v0.4 Last Chicken 4 version (2016)