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

: reverse-vowels-2 ( str -- str' )
  [ clone ] [
    >lower [ vowel? ] find-all
    [ values reverse ] [ keys ] bi
  ] bi                       ! str vowels idxs
  [                          ! str | vowel idx
    pick dupd nth            ! str | vowel idx orig
    1string upper?           ! str | vowel idx t/f
    swapd [ ch>upper ] when  ! str | idx vowel
    set-nth-of               ! str'
  ] 2each                    ! str'
;

: reverse-vowels-2 ( str -- str' )
  [ clone ] [
    >lower [ vowel? ] find-all
    [ values reverse ] [ keys ] bi
  ] bi                       
  [                          
    pick dupd nth            
    1string upper?           
    swapd [ ch>upper ] when  
    set-nth-of               
  ] 2each                    
;