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Challenges Evaluation order of an APL n-train

Haskell, 52 48 45 42 bytes Caught mistake thanks to rak1507 Saved 3 bytes thanks to Hakerh400 f n=n:g[n-1,n-2..1] g(b:c:t)=c:b:g t g t=t Try it online! g takes the rest of the trains. -...

posted 3y ago by user‭  ·  edited 3y ago by user‭

Answer
#7: Post edited by user avatar user‭ · 2021-06-09T22:39:47Z (over 3 years ago)
  • # [Haskell], <s>52</s> <s>48</s> 45 bytes
  • Caught mistake thanks to rak1507
  • <!-- language-all: lang-hs -->
  • f n=n:g[n-1,n-2..1]
  • g(b:c:t)=[c,b]++g t
  • g t=t
  • [Try it online!][TIO-kpop5lec]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpop5lec]: https://tio.run/##y0gszk7Nyfn/P00hzzbPKj06T9dQJ0/XSE/PMJYrXSPJKtmqRNM2OlknKVZbO12hhAuIbUv@5yZm5ilYWSl4@itoaHKBebYKKflcCgq5iQW@8QoFRZl5JQoqIJ5CmkK0IdA4g9j/AA "Haskell – Try It Online"
  • `g` takes the rest of the trains.
  • ```
  • -- This is a fork, so append c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • g(b:c:t)#=[c,b]++g t
  • -- t is either empty or a single monad, so finish it off
  • g t=t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=n:g[n-1,n-2..1]
  • ```
  • # [Haskell], <s>52</s> <s>48</s> <s>45</s> 42 bytes
  • Caught mistake thanks to rak1507
  • Saved 3 bytes thanks to Hakerh400
  • <!-- language-all: lang-hs -->
  • f n=n:g[n-1,n-2..1]
  • g(b:c:t)=c:b:g t
  • g t=t
  • [Try it online!][TIO-kpq203v9]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpq203v9]: https://tio.run/##y0gszk7Nyfn/P00hzzbPKj06T9dQJ0/XSE/PMJYrXSPJKtmqRNM22SrJKl2hhAuIbUv@5yZm5ilYWSl4@itoaHKBebYKKflcCgq5iQW@8QoFRZl5JQoqIJ5CmkK0IdAsg9j/AA "Haskell – Try It Online"
  • `g` takes the rest of the trains.
  • ```
  • -- This is a fork, so append c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • g(b:c:t)#=[c,b]++g t
  • -- t is either empty or a single monad, so finish it off
  • g t=t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=n:g[n-1,n-2..1]
  • ```
#6: Post edited by user avatar user‭ · 2021-06-08T23:51:56Z (over 3 years ago)
  • # [Haskell], <s>52</s> 48 bytes
  • Caught mistake thanks to rak1507
  • <!-- language-all: lang-hs -->
  • f n=[n]++g[n-1,n-2..1]
  • g(b:c:t)=[c,b]++g t
  • g t=t
  • [Try it online!][TIO-kpo1lt1b]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpo1lt1b]: https://tio.run/##HYw5CoAwFAX7nOIVFgkuGMtADmAhHiAEibuoX9HcPy7FFMPAzO5eh20LYQRpQzaOJ0OpTCgtskxaNvFWdcoLbbqk/So8e9E@7G4hKIWyBhfsN43@YMDuzqrBeS3kEX2GEUa@u9yGBw "Haskell – Try It Online"
  • `g` takes the rest of the trains.
  • ```
  • -- This is a fork, so append c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • g(b:c:t)#=[c,b]++g t
  • -- t is either empty or a single monad, so finish it off
  • g t=t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=[n]++g[n-1,n-2..1]
  • ```
  • # [Haskell], <s>52</s> <s>48</s> 45 bytes
  • Caught mistake thanks to rak1507
  • <!-- language-all: lang-hs -->
  • f n=n:g[n-1,n-2..1]
  • g(b:c:t)=[c,b]++g t
  • g t=t
  • [Try it online!][TIO-kpop5lec]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpop5lec]: https://tio.run/##y0gszk7Nyfn/P00hzzbPKj06T9dQJ0/XSE/PMJYrXSPJKtmqRNM2OlknKVZbO12hhAuIbUv@5yZm5ilYWSl4@itoaHKBebYKKflcCgq5iQW@8QoFRZl5JQoqIJ5CmkK0IdA4g9j/AA "Haskell – Try It Online"
  • `g` takes the rest of the trains.
  • ```
  • -- This is a fork, so append c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • g(b:c:t)#=[c,b]++g t
  • -- t is either empty or a single monad, so finish it off
  • g t=t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=n:g[n-1,n-2..1]
  • ```
#5: Post edited by user avatar user‭ · 2021-06-08T12:57:29Z (over 3 years ago)
  • # [Haskell], <s>52</s> 48 bytes
  • Caught mistake thanks to rak1507
  • <!-- language-all: lang-hs -->
  • f n=[n]++g[n-1,n-2..1]
  • g(b:c:t)=[c,b]++g t
  • g t=t
  • [Try it online!][TIO-kpo1lt1b]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpo1lt1b]: https://tio.run/##HYw5CoAwFAX7nOIVFgkuGMtADmAhHiAEibuoX9HcPy7FFMPAzO5eh20LYQRpQzaOJ0OpTCgtskxaNvFWdcoLbbqk/So8e9E@7G4hKIWyBhfsN43@YMDuzqrBeS3kEX2GEUa@u9yGBw "Haskell – Try It Online"
  • `g` takes the rest of the trains.
  • ```
  • --- This is a dyadic train, so append c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • g(b:c:t)#=[c,b]++g t
  • -- t is either empty or a single monad, so finish it off
  • g t=t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=[n]++g[n-1,n-2..1]
  • ```
  • # [Haskell], <s>52</s> 48 bytes
  • Caught mistake thanks to rak1507
  • <!-- language-all: lang-hs -->
  • f n=[n]++g[n-1,n-2..1]
  • g(b:c:t)=[c,b]++g t
  • g t=t
  • [Try it online!][TIO-kpo1lt1b]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpo1lt1b]: https://tio.run/##HYw5CoAwFAX7nOIVFgkuGMtADmAhHiAEibuoX9HcPy7FFMPAzO5eh20LYQRpQzaOJ0OpTCgtskxaNvFWdcoLbbqk/So8e9E@7G4hKIWyBhfsN43@YMDuzqrBeS3kEX2GEUa@u9yGBw "Haskell – Try It Online"
  • `g` takes the rest of the trains.
  • ```
  • --- This is a dyadic train, so append c (monad) and b (dyad)
  • -- This is a fork, so append c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • g(b:c:t)#=[c,b]++g t
  • -- t is either empty or a single monad, so finish it off
  • g t=t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=[n]++g[n-1,n-2..1]
  • ```
#4: Post edited by user avatar user‭ · 2021-06-08T12:56:13Z (over 3 years ago)
  • # [Haskell], 50 bytes
  • <!-- language-all: lang-hs -->
  • f n=[n-1,n-2..1]#[n]
  • (b:c:t)#a=t#a++[c,b]
  • t#a=a++t
  • [Try it online!][TIO-kpn9kiha]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpn9kiha]: https://tio.run/##y0gszk7Nyfn/P00hzzY6T9dQJ0/XSE/PMFY5Oi@WSyPJKtmqRFM50bZEOVFbOzpZJymWC8i0BXJK/ucmZuYpWFkpePoraGhygXm2Cin5XAoKuYkFvvEKBUWZeSUKKiCeQppCtCHQWIPY/wA "Haskell – Try It Online"
  • `#` takes a list of numbers representing a previously processed sub-train on the right, and the rest of the trains on the left.
  • ```
  • --- This is a dyadic train, so appending c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • (b:c:t)#a=t#a++[c,b]
  • -- t is either empty or a single monad, so finish it off
  • t#a=a++t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=[n-1,n-2..1]#[n]
  • ```
  • # [Haskell], <s>52</s> 48 bytes
  • Caught mistake thanks to rak1507
  • <!-- language-all: lang-hs -->
  • f n=[n]++g[n-1,n-2..1]
  • g(b:c:t)=[c,b]++g t
  • g t=t
  • [Try it online!][TIO-kpo1lt1b]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpo1lt1b]: https://tio.run/##HYw5CoAwFAX7nOIVFgkuGMtADmAhHiAEibuoX9HcPy7FFMPAzO5eh20LYQRpQzaOJ0OpTCgtskxaNvFWdcoLbbqk/So8e9E@7G4hKIWyBhfsN43@YMDuzqrBeS3kEX2GEUa@u9yGBw "Haskell – Try It Online"
  • `g` takes the rest of the trains.
  • ```
  • --- This is a dyadic train, so appending c (monad) and b (dyad)
  • -- This is a dyadic train, so append c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • g(b:c:t)#=[c,b]++g t
  • -- t is either empty or a single monad, so finish it off
  • g t=t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=[n]++g[n-1,n-2..1]
  • ```
#3: Post edited by user avatar user‭ · 2021-06-07T23:51:52Z (over 3 years ago)
  • # [Haskell], 50 bytes
  • <!-- language-all: lang-hs -->
  • f n=[n-1,n-2..1]#[n]
  • (b:c:t)#a=t#a++[c,b]
  • t#a=a++t
  • [Try it online!][TIO-kpn9kiha]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpn9kiha]: https://tio.run/##y0gszk7Nyfn/P00hzzY6T9dQJ0/XSE/PMFY5Oi@WSyPJKtmqRFM50bZEOVFbOzpZJymWC8i0BXJK/ucmZuYpWFkpePoraGhygXm2Cin5XAoKuYkFvvEKBUWZeSUKKiCeQppCtCHQWIPY/wA "Haskell – Try It Online"
  • # [Haskell], 50 bytes
  • <!-- language-all: lang-hs -->
  • f n=[n-1,n-2..1]#[n]
  • (b:c:t)#a=t#a++[c,b]
  • t#a=a++t
  • [Try it online!][TIO-kpn9kiha]
  • [Haskell]: https://www.haskell.org/
  • [TIO-kpn9kiha]: https://tio.run/##y0gszk7Nyfn/P00hzzY6T9dQJ0/XSE/PMFY5Oi@WSyPJKtmqRFM50bZEOVFbOzpZJymWC8i0BXJK/ucmZuYpWFkpePoraGhygXm2Cin5XAoKuYkFvvEKBUWZeSUKKiCeQppCtCHQWIPY/wA "Haskell – Try It Online"
  • `#` takes a list of numbers representing a previously processed sub-train on the right, and the rest of the trains on the left.
  • ```
  • -- This is a dyadic train, so appending c (monad) and b (dyad)
  • -- and continue with the rest of the train
  • (b:c:t)#a=t#a++[c,b]
  • -- t is either empty or a single monad, so finish it off
  • t#a=a++t
  • ```
  • `f` simply starts it off with the last function `n` and the other trains `1..n-1` (in reverse).
  • ```
  • f n=[n-1,n-2..1]#[n]
  • ```
#2: Post edited by user avatar user‭ · 2021-06-07T23:48:47Z (over 3 years ago)
#1: Initial revision by user avatar user‭ · 2021-06-07T23:47:52Z (over 3 years ago) 
# [Haskell], 50 bytes

<!-- language-all: lang-hs -->

    f n=[n-1,n-2..1]#[n]
    (b:c:t)#a=t#a++[c,b]
    t#a=a++t

[Try it online!][TIO-kpn9kiha]

[Haskell]: https://www.haskell.org/
[TIO-kpn9kiha]: https://tio.run/##y0gszk7Nyfn/P00hzzY6T9dQJ0/XSE/PMFY5Oi@WSyPJKtmqRFM50bZEOVFbOzpZJymWC8i0BXJK/ucmZuYpWFkpePoraGhygXm2Cin5XAoKuYkFvvEKBUWZeSUKKiCeQppCtCHQWIPY/wA "Haskell – Try It Online"