mirror of
https://github.com/ilyakooo0/urbit.git
synced 2024-12-18 20:31:40 +03:00
76 lines
1.5 KiB
Plaintext
76 lines
1.5 KiB
Plaintext
|
Author: Curtis Yarvin (curtis.yarvin@gmail.com)
|
||
|
|
Date: 3/28/2008
|
||
|
|
Version: 0.12
|
||
|
|
|
||
|
|
1. Introduction
|
||
|
|
|
||
|
|
This file defines one function, "nock."
|
||
|
|
|
||
|
|
nock is in the public domain.
|
||
|
|
|
||
|
|
2. Data
|
||
|
|
|
||
|
|
A "noun" is either an "atom" or a "cell." An "atom" is an unsigned
|
||
|
|
integer of any size. A "cell" is an ordered pair of any two nouns,
|
||
|
|
the "head" and "tail."
|
||
|
|
|
||
|
|
3. Semantics
|
||
|
|
|
||
|
|
nock maps one noun to another. It doesn't always terminate.
|
||
|
|
|
||
|
|
4. Pseudocode
|
||
|
|
|
||
|
|
nock is defined in a pattern-matching pseudocode, below.
|
||
|
|
|
||
|
|
Parentheses enclose cells. (a b c) is (a (b c)).
|
||
|
|
|
||
|
|
5. Definition
|
||
|
|
|
||
|
|
5.1 Transformations
|
||
|
|
|
||
|
|
*(a (b c) d) => (*(a b c) *(a d))
|
||
|
|
*(a 0 b) => /(b a)
|
||
|
|
*(a 1 b) => (b)
|
||
|
|
*(a 2 b c) => *(*(a b) c)
|
||
|
|
*(a 3 b) => **(a b)
|
||
|
|
*(a 4 b) => &*(a b)
|
||
|
|
*(a 5 b) => ^*(a b)
|
||
|
|
*(a 6 b) => =*(a b)
|
||
|
|
|
||
|
|
*(a 7 b c d) => *(a 3 (0 1) 3 (1 c d) (1 0) 3 (1 2 3) (1 0) 5 5 b)
|
||
|
|
*(a 8 b c) => *(a 2 (((1 0) b) c) 0 3)
|
||
|
|
*(a 9 b c) => *(a c)
|
||
|
|
|
||
|
|
*(a) => *(a)
|
||
|
|
|
||
|
|
5.2 Operators
|
||
|
|
|
||
|
|
5.2.1 Goto (*)
|
||
|
|
|
||
|
|
*(a) -> nock(a)
|
||
|
|
|
||
|
|
5.2.2 Deep (&)
|
||
|
|
|
||
|
|
&(a b) -> 0
|
||
|
|
&(a) -> 1
|
||
|
|
|
||
|
|
5.2.4 Bump (^)
|
||
|
|
|
||
|
|
^(a b) -> ^(a b)
|
||
|
|
^(a) -> a + 1
|
||
|
|
|
||
|
|
5.2.5 Same (=)
|
||
|
|
|
||
|
|
=(a a) -> 0
|
||
|
|
=(a b) -> 1
|
||
|
|
=(a) -> =(a)
|
||
|
|
|
||
|
|
5.2.6 Snip (/)
|
||
|
|
|
||
|
|
/(1 a) -> a
|
||
|
|
/(2 a b) -> a
|
||
|
|
/(3 a b) -> b
|
||
|
|
/((a + a) b) -> /(2 /(a b))
|
||
|
|
/((a + a + 1) b) -> /(3 /(a b))
|
||
|
|
/(a) -> /(a)
|