Tacit programming: Difference between revisions

A train is a series of functions in isolation. An isolated function is either surrounded by parentheses or named. Below, <source lang=apl inline>⍺</source> and <source lang=apl inline>⍵</source> refer to the arguments of the train. <source lang=apl inline>f</source>, <source lang=apl inline>g</source>, and <source lang=apl inline>h</source> are functions (which themselves can be tacit or not), and <source lang=apl inline>A</source> is an array. The arguments are processed by the following rules:

A 3-train is a ''fork'':

{|

|-

|<source lang=apl>⍺ (A g h) ⍵</source>|| {{←→}} ||<source lang=apl>A g (⍺ h ⍵)</source>

|}

In [[Dyalog APL]], analysis of trains is assisted by a [[user command]] <source lang=apl inline>]Boxing on</source>. This is achieved by executing the command <source lang=apl inline>]Boxing on</source> and then entering a train without any parameters. A structure of the train will be displayed.

<source lang=apl>

       ]Boxing on

       ((+.×⍨⊢~∘.×⍨)1↓⍳)    ⍝ the train to be analysed

┌───────────────────────────────┬───────┐

│┌───────────┬─────────────────┐│┌─┬─┬─┐│

││└───────┴─┘││ │ ││└─┴─┴─┘│ ││││      │

││          ││ │ │└───────┴─┘│││      │

<source lang=apl>

       ]Boxing on -trains=tree

       ((+.×⍨⊢~∘.×⍨)1↓⍳)    ⍝ the train to be analysed

     ┌───┴───┐   

+ ×  ┌┴┐       

       ∘ ×       

</source>