Beside: Difference between revisions

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{{Built-in|Beside|∘}}, '''Compose''' or '''After''' is a [[primitive operator]]. It shares the glyph <source lang=apl inline>∘</source> with [[Bind]]. Called [[Dyadic function|dyadically]] with function operands <source lang=apl inline>f</source> and <source lang=apl inline>g</source>, it uses <source lang=apl inline>g</source> [[Monadic function|monadically]] to pre-processes the right argument before applying <source lang=apl inline>f</source> to the given left argument and pre-processed right argument. Called [[Monadic function|monadically]] with operands <source lang=apl inline>f</source> and <source lang=apl inline>g</source>, it applies <source lang=apl inline>f</source> to the result of applying <source lang=apl inline>g</source> to the argument.
{{Built-in|Beside|∘}}, '''Compose''' or '''After''' is a [[primitive operator]]. It shares the glyph [[Jot]] (<source lang=apl inline>∘</source>) with [[Bind]]. Called [[Dyadic function|dyadically]] with function operands <source lang=apl inline>f</source> and <source lang=apl inline>g</source>, it uses <source lang=apl inline>g</source> [[Monadic function|monadically]] to pre-processes the right argument before applying <source lang=apl inline>f</source> to the given left argument and pre-processed right argument. Called [[Monadic function|monadically]] with operands <source lang=apl inline>f</source> and <source lang=apl inline>g</source>, it applies <source lang=apl inline>f</source> to the result of applying <source lang=apl inline>g</source> to the argument.


In usage, <source lang=apl inline>X f∘g Y</source> is equivalent to <source lang=apl inline>X f g Y</source>, and <source lang=apl inline>f∘g Y</source> is equivalent to <source lang=apl inline>f g Y</source>. Thus, beside can be defined as the [[dop]] <source lang=apl inline>{⍺←⊢ ⋄ ⍺ ⍺⍺ ⍵⍵ ⍵}</source>.
In usage, <source lang=apl inline>X f∘g Y</source> is equivalent to <source lang=apl inline>X f g Y</source>, and <source lang=apl inline>f∘g Y</source> is equivalent to <source lang=apl inline>f g Y</source>. Thus, beside can be defined as the [[dop]] <source lang=apl inline>{⍺←⊢ ⋄ ⍺ ⍺⍺ ⍵⍵ ⍵}</source>.

Revision as of 06:14, 28 July 2022

Beside (), Compose or After is a primitive operator. It shares the glyph Jot () with Bind. Called dyadically with function operands f and g, it uses g monadically to pre-processes the right argument before applying f to the given left argument and pre-processed right argument. Called monadically with operands f and g, it applies f to the result of applying g to the argument.

In usage, X fg Y is equivalent to X f g Y, and fg Y is equivalent to f g Y. Thus, beside can be defined as the dop { ⍺⍺ ⍵⍵ }.

Examples

When used monadically, fg behaves the same as an atop:

      -÷ 2 
¯0.5
      ⍝ same as
      -(÷2)
¯0.5

When used dyadically, fg forms a dyadic hook:

      'oy''yo'
1
      ⍝ same as
      'oy'≡⌽'yo'
1

When used monadically with Commute, fg forms a monadic hook:

      'UwU'
1
      ⍝ same as this, because operators are left-associative, unlike functions which are right-associative
      ()'UwU'
1
      ⍝ same as
      'UwU'≡⌽'UwU'
1

External links

Lessons

Documentation


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