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* Objectives
** efficient
*** compact
*** support primitives
*** avoid copying/boxing
** general
** extensible
** self-describing
** avoid platform specifics
* Extensibility
** fixed set of core types
** extension types in terms of core types
*** avoid blobs
** no type descriptors, just components
*** enough to skip unknown
* Core Types
| Tag | Fressian | Notes |
|--------+----------+--------------------------------------------------|
| null | null | not really a type, but possible value everywhere |
| true | true | special value |
| false | false | special value |
| int | int | |
| double | double | |
| float | float | |
| string | string | |
| bytes | bytes | array of bytes in user semantics |
| list | list | |
| struct | struct | must supply type tag |
* Standard Extension Types
| Tag | size | struct | notes |
|---------+------+---------------+-------------------------------------------|
| map | 1 | list<k,v> | |
| set | 1 | list | |
| inst | 1 | int | ms since 1970 |
| sym | 2 | string,string | |
| uuid | 1 | bytes | |
| uri | 1 | string | |
| bigint | 1 | bytes | signed, two's complement, msb first |
| bigdec | 2 | bytes,int | val (as per integer), scale |
| regex | 1 | string | |
| sym | 2 | ns, name | |
| key | 2 | ns, name | |
| (array) | 2 | count, vals | int, long, float, double, boolean, Object |
* Writer Interface
** org.fressian.Writer
* Tagged interface
In order to support construction, writing and reading of (esp. nested)
values of types for which there are no mappings, or no unique
mappings, or coercion is required, a single Tagged type must be
present. write(Object) must be able to distinguish Tagged objects.
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