# Dit API

## Structures

```
LineIndex: 5 bytes
  - type: 1 byte
  - data: 4 bytes
  
Current: 0
Last: 0
Number: 0
CurrentPlus: i32
Bookmark: FieldIndex
FirstRegex: FieldIndex
LastRegex: FieldIndex
  
LineRange: 10 bytes
  - start: LineIndex (5 bytes)
  - end:   LineIndex (5 bytes)
  
FieldIndex: 4 bytes

BufferId: 1 byte
```

## Commands

Commands, for the most part, are contained within a single byte slice in the
first message field. The other fields will be used if the command needs to
reference a string or a file, using the `FieldIndex` type. Those fields can be
set to null if the field index is zero. The first byte indicates which command
is being requested. If the calling program has opened multiple buffers, then it
can optionally specify the buffer id by adding it to the end of the byte slice.
Otherwise, the implied buffer is the last one that has been used by the calling
program.

```
append     = [0,  LineIndex, FieldIndex, BufferId?]
change     = [1,  LineRange, FieldIndex, BufferId?]
delete     = [2,  LineRange, BufferId?]
open       = [3,  FieldIndex] returns BufferId
setfile    = [4,  FieldIndex, BufferId?]
find       = [5,  LineRange, FieldIndex, BufferId?] returns number[]
insert     = [6,  LineIndex, FieldIndex, BufferId?]
join       = [7,  LineRange, BufferId?]
bookmark   = [8,  LineIndex, FieldIndex, BufferId?]
move       = [9,  LineRange, LineIndex, BufferId?]
read       = [10, LineRange, BufferId?] returns [LineRange, String]
substitute = [11, LineRange, FieldIndex, FieldIndex, BufferId?]
copy       = [12, LineRange, FieldIndex, BufferId?]
undo       = [13, BufferId?]
write      = [14, BufferId?]
linenumber = [15, BufferId?] returns number
jump       = [16, LineIndex, BufferId?]
```

### Append