ershov / js-church

Church encoding in javascript (experiment)

js-church: Church encoding in javascript experiment

This is based on Programming with Nothing article and the following links:

• Programming with Nothing
• Sources in Ruby: pedant and story
• Church Encoding in Wiki

NB: Ruby to Javascript conversion

The code in Ruby was converted to Javascript using these commands in Vim:

• .. from Ruby to JS:

  set ft=javascript
  %s/#/\/\/                                  " fix comments
  %s/\V[/(/g                                 " alter function call: [] -> ()
  %s/\V]/)/g                                 "
  %s/\v\s*\-\>\s*(\w+)\s*\{\s*/( \1 => /g    " alter function definition
  %s/\V}/)/g                                 " grouping (closing)
  %s/\v<_>/v/g                               " replace "_" variable with "v"
  w !node                                    " run with node js
  

  ... search for ((...)) and remove extra matching parens: search string: \v\(\( use macro: %x``x

• .. from JS to strings (js):

  set ft=javascript
  %s/\/\/.*//                                " strip comments
  %s/\v^(\w+)\s*\=\s*(.*)\s*$/\1 = `\2`;/    " function definitions
  %s/\v^@<!<([A-Z_]+)>/\$\{\1\}/g            " make use of string interpolation
  %s/\v(\w@<! )|( \w@!)//g                   " remove whitespace which is not between the letters
  $a                                         " append test code to file:
  console.log(`0\n(${TO_INTEGER})(${ZERO})`);
  console.log(`1\n(${TO_INTEGER})(${ONE})`);
  console.log(`10\n(${TO_INTEGER})(${TEN})`);
  console.log(`[1..10]\n${TO_ARRAY}(${RANGE}(${ONE})(${TEN})).map(${TO_INTEGER})`)
  console.log(`[1..100]\n${TO_ARRAY}(${RANGE}(${ONE})(${HUNDRED})).map(${TO_INTEGER})`)
  console.log(`fizzbuzz(100)\n${TO_ARRAY}(${FIZZBUZZ}(${HUNDRED})).map(${TO_STRING})`)
  .
  w !node                                    " run in Node
  

• .. from JS to strings (perl):

  set ft=perl
  %s/\/\/.*//                                " strip comments
  %s/\v^(\w+)\s*\=\s*(.*)\s*$/\1 = "\2";/    " function definitions
  %s/\v([A-Z_]+)/\$\1/g                      " make use of string interpolation
  $a                                         " append test code to file:
  print $FIZZBUZZ
  .
  w !perl                                    " run in perl