Symbol Goto: Difference between revisions

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===Conditional branch===
===Conditional branch===
The value to the right of the arrow is a boolean expression surrounded by parentheses, followed by the line number to transfer to if the expression is true.


===Unconditional branch===
===Unconditional branch===

Revision as of 20:37, 11 September 2015

→ — Branch to a line in a function — Keystroke ALT+] — Character 8594 or 0x2192

APLKB-Goto.png

Alternate Names

This symbol is also known as right arrow or APL text symbol {rightarrow}.

Usage

The goto symbol may be used as a conditional branch (branch based on a comparison) or an unconditional branch, or it may be used to exit a function. It is most often used in a function to transfer control, but can be used from the session manager to transfer to a line in a suspended function.

Conditional branch

The value to the right of the arrow is a boolean expression surrounded by parentheses, followed by the line number to transfer to if the expression is true.

Unconditional branch

The goto symbol is followed on the right either by the line number or a label. Execution continues in the function at that line (unless the line specified is 0, in which case the function exits.)

Exit Function

The goto symbol may be used to exit a function and return to the calling function (or return to the session manager if the function was called by the user typing its name) by using 0 as the line number to goto.

Examples

Exit Function

In the following example, function one calls function two, which exits part way through the function, returning to function 1.

∆one

[0] one
[1] 'This is one'
[2] two
[3] 'return to one from two'

∆
∆two

[0] two
[1] 'This is two'
[2] →0
[3] 'Two Continues'

∆
one

This is one
This is two
return to one from two

Another Example see: Control Structures - Branching Example


See Also
System Commands System Variables and Functions Operators


Keyboard
A+S ⍪ ≡ ≢ ⍒ ⍋ ⌽ ⍉ ⊖ ⍟ ⍱ ⍲ ⍠ ⌹
Alt ⋄ ¨ ¯ < ≤ ∅ ≥ > ≠ ∨ ∧ × ÷
Sh ~ ! @ # $ % ^ & * ( ) _ +
Key ` 1 2 3 4 5 6 7 8 9 0 - =
A+S ⍷ √ ⍨ ⍸ ⍥ ⍣ ⍞ ⍬ ⊣
Alt ? ⍵ ∊ ⍴ § ↑ ↓ ⍳ ○ π ← → ⊢
Sh Q W E R T Y U I O P { } |
Key q w e r t y u i o p [ ] \
A+S ∫ ∂ ⌻ ⍢ ⍙ ⍤ ⍫ ⌷
Alt ⍺ ⌈ ⌊ ∞ ∇ ∆ ∘ ‼ ⎕ ⍎ ⍕
Sh A S D F G H J K L : "
Key a s d f g h j k l ; '
A+S ⊆ ⊇ χ ⍡ ⍭ ⊙
Alt ⊂ ⊃ ∩ ∪ ⊥ ⊤ ⍦ ⍝ ⍀ ⌿
Sh Z X C V B N M < > ?
Key z x c v b n m , . /
NARS 2000 Lang
Tool
Bar 		← → + - × ÷ * ⍟ ⌹ ○ ! ? √ | ⌈ ⌊ ⊥ ⊤ ⊣ ⊢
≡ ≢ < ≤ = ≥ > ≠ ∨ ∧ ⍱ ⍲ ↑ ↓ ⊂ ⊃ ⌷ ⍋ ⍒
⍳ ∊ ⍸ ⍷ ∪ ∩ ⊆ ⊇ ~ § π .. , ⍪ ⍴ ⌽ ⊖ ⍉
/ \ ⌿ ⍀ ⊙ ¨ ⍨ ⍤ ⍣ ⍡ ⍥ ⍦ . ∘ ⍠ ‼ ⌻ ∂ ∫ ⍞ ⎕ ⍎ ⍕
⋄ ⍝ ∇ ∆ ⍙ _ ⍺ ⍵ ¯ ⍬ ∞ ∅
Second Row i j k i j k l g p r v x

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