4,494
edits
Tacit programming: Difference between revisions
Jump to navigation
Jump to search
→Summary of rules: moved to Function composition
(→Trains: hooks) |
(→Summary of rules: moved to Function composition) |
||
| (10 intermediate revisions by 5 users not shown) | |||
| Line 45: | Line 45: | ||
The ''left tine'' of a fork can be an array: | The ''left tine'' of a fork can be an array: | ||
{| | {| | ||
|<source lang=apl> (A g h)</source>|| {{←→}} ||<source lang=apl>A g ( h ⍵)</source> | |<source lang=apl> (A g h) ⍵</source>|| {{←→}} ||<source lang=apl>A g ( h ⍵)</source> | ||
|- | |- | ||
|<source lang=apl>⍺ (A g h) ⍵</source>|| {{←→}} ||<source lang=apl>A g (⍺ h ⍵)</source> | |<source lang=apl>⍺ (A g h) ⍵</source>|| {{←→}} ||<source lang=apl>A g (⍺ h ⍵)</source> | ||
| Line 66: | Line 66: | ||
|<source lang=apl>⍺ (g h) ⍵</source>|| {{←→}} ||<source lang=apl>⍺ g (h ⍵)</source> | |<source lang=apl>⍺ (g h) ⍵</source>|| {{←→}} ||<source lang=apl>⍺ g (h ⍵)</source> | ||
|} | |} | ||
=== Problems caused by function-operator overloading === | |||
Trains that use a [[Function-operator_overloading|hybrid function-operator]] in its [[function]] role can run into the problems with the hybrid being parsed as a monadic [[operator]] instead of as a function. This happens when a function appears to the immediate left of the hybrid, causing this function to be bound as the hybrid's operand — the hybrid taking on an operator role — rather than supplying a left [[argument]] or post-processing the result. | |||
For example, the attempted [[#3-trains|fork]] <source lang=apl inline>f/h</source> is actually parsed as the [[#2-trains|atop]] <source lang=apl inline>(f/)h</source> and the attempted atop <source lang=apl inline>f/</source> is actually parsed as a [[Windowed Reduce|Windowed Reduction]]. There are multiple [[Function-operator_overloading#Mitigation|ways to mitigate this issue]]. For example, the fork can be enforced using the [[Atop (operator)|Atop operator]] by applying identity to the hybrid's result as <source lang=apl inline>f⊢⍤/h</source> and the atop can be enforced by using the explicit Atop operator instead of a 2-train; <source lang=apl inline>f⍤/</source>. | |||
No problem presents when left argument is supplied as an array (literal or by name reference) and when the hybrid is the leftmost token. For example, <source lang=apl inline>1 0 1/⌽</source> and <source lang=apl inline>/,⊃</source> are parsed as forks. | |||
== Debugging == | == Debugging == | ||
| Line 191: | Line 198: | ||
+.×⍨(⊢1↓⍳17)~∘.×⍨1↓⍳17 ⍝ Fork evalution | +.×⍨(⊢1↓⍳17)~∘.×⍨1↓⍳17 ⍝ Fork evalution | ||
+.×⍨(1↓⍳17)~∘.×⍨1↓⍳17 ⍝ ⊢ evaluation | +.×⍨(1↓⍳17)~∘.×⍨1↓⍳17 ⍝ ⊢ evaluation | ||
+.×⍨2 3 5 7 11 13 | +.×⍨2 3 5 7 11 13 17 ⍝ numbers 2 through 17 without those appearing in their multiplication table are primes | ||
666 ⍝ the sum of the squares of the primes up to 17 | 666 ⍝ the sum of the squares of the primes up to 17 | ||
</source> | </source> | ||
| Line 212: | Line 219: | ||
== External links == | == External links == | ||
=== Tutorials === | === Tutorials === | ||
* Dyalog: [https://help.dyalog.com/16.0/Content/RelNotes14.0/Function%20Trains.htm version 14.0 release notes] | <div style="column-width:30em"> | ||
==== In text form ==== | |||
* [[Learning APL]]: [https://xpqz.github.io/learnapl/tacit.html Trainspotting] | |||
* [[Documentation_suites#Dyalog_APL|Dyalog documentation]]: [https://help.dyalog.com/16.0/Content/RelNotes14.0/Function%20Trains.htm version 14.0 release notes] | |||
* [[Dfns workspace]]: [https://dfns.dyalog.com/n_tacit.htm Translation of <nowiki>[dfns]</nowiki> into tacit form] | * [[Dfns workspace]]: [https://dfns.dyalog.com/n_tacit.htm Translation of <nowiki>[dfns]</nowiki> into tacit form] | ||
* [[APL Cultivation]]: [https://chat.stackexchange.com/rooms/52405/conversation/lesson-23-transcribing-to-and-reading-trains Transcribing to and reading trains] | * [[APL Cultivation]]: [https://chat.stackexchange.com/rooms/52405/conversation/lesson-23-transcribing-to-and-reading-trains Transcribing to and reading trains] | ||
* [[APLtrainer]]: [https://www.youtube.com/watch?v=kt4lMZbn-so How to read trains in Dyalog APL code] | * gitonthescene: [https://gist.github.com/gitonthescene/666c77ee3ed0ae0a79cf8e057584b7fd Forks: Spoon fed] | ||
* [[APLtrainer]]: [https://www.youtube.com/watch?v=A2LqqBosvY0 Function trains in APL] | * gitonthescene: [https://gist.github.com/gitonthescene/5e9c25ab9edd2f2ce0d5ad38d8a8b2b4 Training day] | ||
* [[Dyalog webinar]]: [https://www.youtube.com/watch?v=Enlh5qwwDuY?t=440 Train Spotting in Dyalog APL] | |||
* [[Dyalog '13]]: [https://www.youtube.com/watch?v=7-93GzDqC08 Train Spotting in Version 14.0] | |||
==== Videos ==== | |||
* [[APLtrainer]]: [https://www.youtube.com/watch?v=kt4lMZbn-so How to read trains in Dyalog APL code] | |||
* [[APLtrainer]]: [https://www.youtube.com/watch?v=A2LqqBosvY0 Function trains in APL] | |||
* [[Dyalog webinar]]: [https://www.youtube.com/watch?v=Enlh5qwwDuY?t=440 Train Spotting in Dyalog APL] | |||
* [[Dyalog '13]]: [https://www.youtube.com/watch?v=7-93GzDqC08 Train Spotting in Version 14.0] | |||
</div> | |||
=== Documentation === | === Documentation === | ||