https://github.com/ktakashi/r6rs-msgpack

MessagePack for R6RS Scheme / msgpack.org[Scheme]
https://github.com/ktakashi/r6rs-msgpack

messagepack msgpack r6rs r6rs-scheme scheme

Last synced: 16 days ago
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MessagePack for R6RS Scheme / msgpack.org[Scheme]

• Host: GitHub
• URL: https://github.com/ktakashi/r6rs-msgpack
• Owner: ktakashi
• Created: 2013-02-06T10:51:19.000Z (almost 12 years ago)
• Default Branch: master
• Last Pushed: 2013-10-17T19:32:51.000Z (about 11 years ago)
• Last Synced: 2024-10-10T16:13:38.710Z (29 days ago)
• Topics: messagepack, msgpack, r6rs, r6rs-scheme, scheme
• Language: Scheme
• Homepage:
• Size: 152 KB
• Stars: 13
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
MessagePack for R6RS Scheme

========

This is an implementation of [MessagePack](http://msgpack.org/) for 

R6RS Scheme.

API references

--------

_Function_ (pack! bv message)   

_Function_ (pack! bv message offset)   

Pack *message* to message pack format bytevector and put it into the

*bv* destructively. Given *bv* must have enough length to hold the message.

Optional argument *offset* indicates where to start with, default is 0.  

_Function_ (pack message)   

The same as **pack!** but this one creates a new bytevector.

_Function_ (pack-size message)

Calculate the converted message size.

_Function_ (unpack bv)   

_Function_ (unpack bv offset)  

Unpack the given message format bytevector to Scheme object.

Optional argument *offset* indicates where to start with, default is 0.  

_Function_ (get-unpack in)

Unpack the given binary input port to Scheme object.

Conversion rules

--------

As you already know, Scheme doesn't have static types so the conversion of

Scheme objects to message pack data might cause unexpected results. To avoid

it, I will describe how conversion works.

### Scheme to message pack

#### Integer conversion

The library automatically decides proper size. More specifically, if it

can fit to message pack's fixnum then library uses it, so are uint8-64.

If the number is too big, then an error is raised. Users must know it tries

to use uint as much as possible. If the given number was negative then

sint will be used.

#### Floating point conversion

Unfortunately R6RS doesn't have difference between float and double. So

when flonum is given then it always converts to double number.

#### Collection conversion

Message pack has collections which are map and array. And these are associated

with alist (association list) and vector respectively. When you want to convert

alist to message pack data, then you need to make sure the _cdr_ part will be

the data and if you put _(("key" "value))__ then it will be converted to nested

map.

The collection size calculation is done automatically. It tries to use the

smallest size.

### Message pack to Scheme

The other way around is easy, it can simply restore the byte data to Scheme

object. Following describes the conversion rules;

Positive fixnum -> integer   

Negative fixnum -> integer   

uint8, uint16, uint32, uint64 -> integer   

sint8, sint16, sint32, sint64 -> integer   

Map -> alist   

Array -> vector   

fixstr, str8, str16, str32 -> string

bit8, bit16, bit32 -> bytevector

Tested Scheme implementations

--------

[Sagittarius Scheme](http://code.google.com/p/sagittarius-scheme/)

[Mosh Scheme](http://code.google.com/p/mosh-scheme/)

[Ypsilon](http://code.google.com/p/ypsilon/)

Your contributions are always welcome.

TODO

--------

* More testing

* Extended type handling