Add documentation
This commit is contained in:
parent
aa34ac6470
commit
fb50e68e85
|
@ -0,0 +1,12 @@
|
||||||
|
Commands
|
||||||
|
--------
|
||||||
|
Gir brainfuck has only the base 8 commands `+-<>[].,`
|
||||||
|
|
||||||
|
Tape
|
||||||
|
----
|
||||||
|
Gir's tape is unbounded in both directions and made out of unsigned 8-bit
|
||||||
|
cells that wrap around
|
||||||
|
|
||||||
|
IO
|
||||||
|
--
|
||||||
|
`.` and `,` operate on a utf-8 stream. `,` produces `0` on EOF
|
|
@ -0,0 +1,72 @@
|
||||||
|
Gir uses two types of IR, with and without offsets
|
||||||
|
|
||||||
|
Without offsets
|
||||||
|
---------------
|
||||||
|
This is produced by `parse`. Each subsection shows the properties the
|
||||||
|
command object of that type has in IR without offsets
|
||||||
|
|
||||||
|
### add
|
||||||
|
type | `add`
|
||||||
|
value | The number to add to current cell
|
||||||
|
|
||||||
|
Generated on `+` and `-`
|
||||||
|
|
||||||
|
### moveHead
|
||||||
|
type | `moveHead`
|
||||||
|
value | The number of steps to move the tape head right
|
||||||
|
|
||||||
|
Generated on `<` and `>`
|
||||||
|
|
||||||
|
### writeByte
|
||||||
|
type | `writeByte`
|
||||||
|
|
||||||
|
Generated on `.`
|
||||||
|
|
||||||
|
### readByte
|
||||||
|
type | `readByte`
|
||||||
|
|
||||||
|
Generated on `,`
|
||||||
|
|
||||||
|
### loop
|
||||||
|
type | `loop`
|
||||||
|
contents | An array of the commands making up the loop body
|
||||||
|
|
||||||
|
Generated on `[`…`]`
|
||||||
|
|
||||||
|
### clear
|
||||||
|
type | `clear`
|
||||||
|
|
||||||
|
Not generated by the parser directly, but generated by optimizations
|
||||||
|
|
||||||
|
|
||||||
|
With offsets
|
||||||
|
------------
|
||||||
|
This is produced by the optimization pass `addOffsetProperties`. Each
|
||||||
|
subsection shows the properties the command object of that type has in IR
|
||||||
|
with offsets
|
||||||
|
|
||||||
|
### add
|
||||||
|
type | `add`
|
||||||
|
value | The number to add to the cell
|
||||||
|
offfset | The location of the cell relative to current tape position
|
||||||
|
|
||||||
|
### moveHead
|
||||||
|
type | `moveHead`
|
||||||
|
value | The number of steps to move the tape head right
|
||||||
|
|
||||||
|
### writeByte
|
||||||
|
type | `writeByte`
|
||||||
|
offset | The location of the cell relative to current tape position
|
||||||
|
|
||||||
|
### readByte
|
||||||
|
type | `readByte`
|
||||||
|
offset | The location of the cell relative to current tape position
|
||||||
|
|
||||||
|
### loop
|
||||||
|
type | `loop`
|
||||||
|
contents | An array of the commands making up the loop body
|
||||||
|
isBalanced | Whether execution of the loop body ends in same cell it started in
|
||||||
|
|
||||||
|
### clear
|
||||||
|
type | `clear`
|
||||||
|
offset | The location of the cell relative to current tape position
|
|
@ -0,0 +1,38 @@
|
||||||
|
Gir has three optimization passes.
|
||||||
|
|
||||||
|
joinAdjacentOps
|
||||||
|
---------------
|
||||||
|
consumes | commands without offsets
|
||||||
|
produces | commands without offsets
|
||||||
|
unknown commands | passed through unmodified
|
||||||
|
acts on | `moveHead`, `add`
|
||||||
|
|
||||||
|
`joinAdjacentOps` joins adjacent `moveHead`s and `add`s together. Normally
|
||||||
|
`parse` joins runs of `<>` or `+-` into one command, but if the runs are
|
||||||
|
interrupted by another character two commands get generated. `moveHead`s are
|
||||||
|
joined first, before the pass goes over the generated commands again and
|
||||||
|
joins `add`s.
|
||||||
|
|
||||||
|
transformClearLoops
|
||||||
|
-------------------
|
||||||
|
consumes | commands without offsets
|
||||||
|
produces | commands without offsets
|
||||||
|
unknown commands | passed through unmodified
|
||||||
|
acts on | `loop` with one command, which is `add 1` or `add -1`
|
||||||
|
|
||||||
|
`transformClearLoops` changes loops of the form `[-]` or `[+]` into a single
|
||||||
|
`clear` command.
|
||||||
|
|
||||||
|
addOffsetProperties
|
||||||
|
-------------------
|
||||||
|
consumes | commands without offsets
|
||||||
|
produces | commands with offsets
|
||||||
|
unknown commands | raise UnknownIRError
|
||||||
|
acts on | `moveHead`, `add`, `clear`, `writeByte`, `readByte`, `loop`
|
||||||
|
|
||||||
|
`addOffsetProperties` adds an `offset` property to `add`, `clear`,
|
||||||
|
`writeByte`, and `readByte`. The `offset` tells the offset at which from the
|
||||||
|
current tape head location the operations are performed. It also adds an
|
||||||
|
`isBalanced` property to loops. This property tells if execution of loop
|
||||||
|
body ends at the same cell where it began, which is useful for performing
|
||||||
|
further optimizations.
|
Loading…
Reference in New Issue