this post was submitted on 01 Dec 2024
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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:

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

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Ategon
Andy
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Happy Advent of Code 2024 Everyone! (adventofcode.com)
submitted 1 month ago* (last edited 1 month ago) by Andy to c/concatenative
7 comments fedilink hide all child comments
 

Alright, show me I'm not the only one in this community, and show off some solutions!

Here's my Day 1 solution in Factor (minus imports):

spoiler

: get-input ( -- left-list right-list )
  "aoc-2024.01" "input.txt" vocab-file-lines
  [ split-words harvest ] map unzip
  [ [ string>number ] map ] bi@ ;

: part1 ( -- n )
  get-input
  [ sort ] bi@
  [ - abs ] 2map-sum ;

: part2 ( -- n )
  get-input
  histogram
  '[ dup _ at 0 or * ] map-sum ;

Sadly, Factor doesn't get highlighted properly here, so here it is again as an image:

spoiler

syntax-highlighted screenshot of the code above

I probably won't last the week, but what solutions I do have will be up on GitHub.

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[–] Andy 1 points 1 month ago* (last edited 1 month ago)

Day 4

spoiler

: get-input ( -- rows )
  "vocab:aoc-2024/04/input.txt" utf8 file-lines ;

: verticals ( rows -- lines )
  [ dimension last [0..b) ] keep cols ;

: slash-origins ( rows -- coords )
  dimension
  [ first [0..b) [ 0 2array ] map ] [
    first2 [ 1 - ] [ 1 (a..b] ] bi*
    [ 2array ] with map
  ] bi append ;

: backslash-origins ( rows -- coords )
  dimension first2
  [ [0..b) [ 0 2array ] map ]
  [ 1 (a..b] [ 0 swap 2array ] map ] bi* append ;

: slash ( rows origin -- line )
  first2
  [ 0 [a..b] ]
  [ pick dimension last [a..b) ] bi* zip
  swap matrix-nths ;

: backslash ( rows origin -- line )
  [ dup dimension ] dip first2
  [ over first [a..b) ]
  [ pick last [a..b) ] bi* zip nip
  swap matrix-nths ;

: slashes ( rows -- lines )
  dup slash-origins
  [ slash ] with map ;

: backslashes ( rows -- lines )
  dup backslash-origins
  [ backslash ] with map ;

: word-count ( line word -- n )
  dupd [ reverse ] dip
  '[ _ subseq-indices length ] bi@ + ;

: part1 ( -- n )
  get-input
  { [ ] [ verticals ] [ slashes ] [ backslashes ] } cleave-array concat
  [ "XMAS" word-count ] map-sum ;

: origin-adistances ( rows origins line-quot: ( rows origin -- line ) -- origin-adistances-assoc )
  with zip-with
  "MAS" "SAM" [ '[ [ _ subseq-indices ] map-values ] ] bi@ bi append
  harvest-values
  [ [ 1 + ] map ] map-values ; inline

: a-coords ( origin-adistances coord-quot: ( adistance -- row-delta col-delta ) -- coords )
  '[ first2 [ @ 2array v+ ] with map ] map-concat ; inline

: slash-a-coords ( rows -- coords )
  dup slash-origins [ slash ] origin-adistances
  [ [ 0 swap - ] keep ] a-coords ;

: backslash-a-coords ( rows -- coords )
  dup backslash-origins [ backslash ] origin-adistances
  [ dup ] a-coords ;

: part2 ( -- n )
  get-input [ slash-a-coords ] [ backslash-a-coords ] bi
  intersect length ;

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