Concatenative Programming

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Hello!

This space is for sharing news, experiences, announcements, questions, showcases, etc. regarding concatenative programming concepts and tools.

We'll also take any programming described as:

• pipelined
• stack-oriented
• tacit
• postfix / reverse Polish notation (RPN)

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From Wikipedia:

A concatenative programming language is a point-free computer programming language in which all expressions denote functions, and the juxtaposition of expressions denotes function composition. Concatenative programming replaces function application, which is common in other programming styles, with function composition as the default way to build subroutines.

For example, a sequence of operations in an applicative language like the following:

y = foo(x)
z = bar(y)
w = baz(z)

...is written in a concatenative language as a sequence of functions:

x foo bar baz

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Active Languages

Let me know if I've got any of these misplaced!

Primarily Concatenative

• Forth
• Factor
• Retro
• min
• Joy
• Uiua
• kcats
• iNet
• mlatu
• Execline

Concatenative-ish, Chain-y, Pipe-y, Uniform Function Call Syntax, etc.

• Nim
• Roc
• Unix Pipes
• Cognate
• D Programming Language
• Koka

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Cheat Sheets & Tutorials

• Learn Factor in Y minutes
• A panoramic tour of Factor
• Factor Tutorial Video

Discord

• Concatenative
• Factor

IRC

• #concatenative on irc.libera.chat

Wikis

• concatenative wiki

Wikipedia Topics

• Reverse Polish Notation
• Uniform Function Call Syntax
• Stack-Oriented Programming
• Tacit Programming

Subreddits

• r/concatenative
• r/factor

GitHub Topics

• Stack-Based Language
• Concatenative
• Concatenative Language
• Concatenative Programming Language
• Concatenative Interpreting Language

Blogs

• planet-factor

Practice

• Codewars (Forth, Factor, Nim)
• Advent of Code
• Code Golf (Forth, Factor, Nim)
• Project Euler
• Exercism (Nim)
• Perl Weekly Challenge

MODERATORS

USING: combinators.short-circuit.smart kernel math math.functions math.parser sequences sequences.extras sets unicode ;

: luhn? ( str -- ? )
  " " without
  dup { [ length 2 < ] [ [ digit? ] all? not ] } || [ drop f ] [
    string>digits
    reverse [ <evens> sum ] [ <odds> ] bi
    [ 2 * dup 9 > [ 9 - ] when ] map-sum +
    10 divisor?
  ] if
;

USING: combinators.short-circuit.smart kernel math math.parser rosetta-code.luhn-test sequences sets unicode ;

: ex-luhn? ( str -- ? )
  " " without
  dup {
    [ length 2 < ]
    [ [ digit? ] all? not ]
  } || [ drop f ] [
    string>number luhn?
  ] if
;

USING: combinators.short-circuit.smart kernel math sequences sets unicode validators ;

: ex-luhn? ( str -- ? )
  " " without
  dup {
    [ length 2 < ]
    [ [ digit? ] all? not ]
  } || [ drop f ] [ luhn? ] if
;