Crate autoperm

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Expand description

Autoperm is a tool for generating programs to apply stack effect diagrams.

It is backend agnostic and could be used to generate programs for any language as long as the language implements the Model trait.

A brainfuck backend is provided and accessible with autoperm_bf.

Binary

Installing the crate as a binary gives access to the autoperm command which uses this brainfuck backend as REPL.

cargo install autoperm

Usage:

$ autoperm a b -- b a
[->+<]<[->+<]>>[-<<+>>]<

$ autoperm
a b c -- c a b
[->+<]<[->+<]<[->+<]>>>[-<<<+>>>]<

a -- a a a a
[->>>>+<<<<]>>>>[-<+<+<+<+>>>>]<

a b c d -- d c a b
[->+<]<<[->>+<<]>[-<+>]<<[->>+<<]>>>>[-<<<<+>>>>]<

a b c -- c
<<[-]>[-]>[-<<+>>]<<

a b c d e f -- c d d f e e b
<<<<<[-]>[->>>>>+<<<<<]>[-<<+>>]>[-<+<+>>]>>[-<<+>>]<[->>>+<<<]>>>[-<<+<+>>>]<

The program assumes the memory pointer starts by pointing at the top of the stack. Any “new” cells (cells that are not defined in the input) should start empty. There must also be 1 free cell at the top of the stack for temporary storage.

For example:

(a b c -- c)
start must be:
  a  b *c  0 // a and b are cleared
<<[-]>[-]>[-<<+>>]<<
end:
 *c  0  0  0

(a -- a a a a)
start must be:
  a  0  0  0  0 // note: no 0s are initialized before usage
[->>>>+<<<<]>>>>[-<+<+<+<+>>>>]<
end:
  a  a  a *a  0

A walk through for (a b – a b a b)

a b -- a b a b
<[->>>>+<<<<]>>>>[-<<+<<+>>>>]<<<[->>>+<<<]>>>[-<+<<+>>>]<

# the tape
 0 *1  2  3  T
 a  b  0  0  0

<[->>>>+<<<<]      0 → {T}
*0  1  2  3  T
 0  b  0  0  a

>>>>[-<<+<<+>>>>]  T → {2 0}
 0  1  2  3 *T
 a  b  a  0  0

<<<[->>>+<<<]      1 → {T}
 0 *1  2  3  T
 a  0  a  0  b

>>>[-<+<<+>>>]     T → {1 3}
 0  1  2  3 *T
 a  b  a  b  0

<
 0  1  2 *3  T
 a  b  a  b  0

Modules

  • models
    Predefined models for certain programming languages

Structs

Enums

Traits

  • Model
    The assumed model of computation

Functions