Diamond: Difference between revisions
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__NOTOC__ | __NOTOC__ | ||
{{Article header | |||
|sym={diamond} | |||
|def=Statement separator | |||
|ks=ALT+` (Accent grave) | |||
|char=8900 or x22C4 | |||
|kb=[[File:APLKB-Diamond.png]]}} | |||
==Usage== | ==Usage== | ||
While the diamond operator ('''<big><big>{diamond}</big></big>''') can be used in an immediate statement to the Session Manager, it is most commonly used in a [[functions|function]] to start a new statement '''on the same''' physical line-row of user-code. It is used similarly to the semi colon ('''<big>;</big>''') in C, Pascal, PHP and many other languages, or the colon ('''<big>:</big>''') and backslash ('''<big>\</big>''') in some versions of Basic. It allows another statement to be concisely set on the same line. | |||
'''Note:''' The '''<big><big>{diamond}</big></big>''' operator <u>cannot</u> be used after a [[lamp]] (<big><big>{lamp}</big></big>) comment operator appears on the same line, as all characters after <big><big>{lamp}</big></big> are ignored. | |||
'''Also note''' the '''<big><big>{diamond}</big></big>''' operator represents an <u>exception to the rule</u> that APL's interpreter executes from right to left, since the ''leftmost APL statement'' is executed BEFORE the adjacent APL statement after the next '''<big><big>{diamond}</big></big>''' operator and so on. Each APL statement is executed sequentially '''as if''' listed on multiple lines. The '''<big><big>{diamond}</big></big>''' operator also helps ''condense'' APL code since fewer ''visual'' lines will contain the same amount of APL coding - and in many instances it ''can result'' in cleaner, or easier-to-read-and-understand APL code. | |||
==Examples== | |||
In the first example, the variable K is tested to see if it is greater than or equal to 1. If the test fails, k is set to 1.<br/> | |||
:<code><big>{goto}(k{ge}1)/Xr {diamond} K{:=}1<br/>Xr: ⍝This branch/goto Label is deliberately placed <u>first</u> on its own line!</big></code><br/> | |||
It is the same as | |||
:<code><big>{goto}(k{ge}1)/Xr <br/> K{:=}1<br/>Xr:</big></code><br/> | |||
The following represents more <u>condensed</u> ''':for ... :endfor''' control structure in a user-function than if it were shown in four separate lines:<br><font color=purple><strong> | |||
<code> | |||
A←1 3 5 7 ⋄ :for ii :in ⍳⍴A ⋄ A[ii]←A[ii]*2 ⋄ :endfor ⍝Easier to maintain code if segmented well, esp. when surrounded by long code blocks. | |||
</code></strong></font> | |||
{{ | {{Article footer}} | ||
{{Symbol footer|11|D}} | |||
Latest revision as of 22:03, 21 February 2015
⋄ — Statement separator — Keystroke ALT+` (Accent grave) — Character 8900 or x22C4
[[file:
]]
[[File:{{{kb2}}}]]
Usage
While the diamond operator (⋄) can be used in an immediate statement to the Session Manager, it is most commonly used in a function to start a new statement on the same physical line-row of user-code. It is used similarly to the semi colon (;) in C, Pascal, PHP and many other languages, or the colon (:) and backslash (\) in some versions of Basic. It allows another statement to be concisely set on the same line.
Note: The ⋄ operator cannot be used after a lamp (⍝) comment operator appears on the same line, as all characters after ⍝ are ignored.
Also note the ⋄ operator represents an exception to the rule that APL's interpreter executes from right to left, since the leftmost APL statement is executed BEFORE the adjacent APL statement after the next ⋄ operator and so on. Each APL statement is executed sequentially as if listed on multiple lines. The ⋄ operator also helps condense APL code since fewer visual lines will contain the same amount of APL coding - and in many instances it can result in cleaner, or easier-to-read-and-understand APL code.
Examples
In the first example, the variable K is tested to see if it is greater than or equal to 1. If the test fails, k is set to 1.
→(k≥1)/Xr ⋄ K←1
Xr: ⍝This branch/goto Label is deliberately placed first on its own line!
It is the same as
→(k≥1)/Xr
K←1
Xr:
The following represents more condensed :for ... :endfor control structure in a user-function than if it were shown in four separate lines:
A←1 3 5 7 ⋄ :for ii :in ⍳⍴A ⋄ A[ii]←A[ii]*2 ⋄ :endfor ⍝Easier to maintain code if segmented well, esp. when surrounded by long code blocks.
| See Also | ||
| System Commands | System Variables and Functions | Operators |
| Keyboard | ||||||||||||||
| Alt+Shift | ⍪ | ≡ | ≢ | ⍒ | ⍋ | ⌽ | ⍉ | ⊖ | ⍟ | ⍱ | ⍲ | ⍠ | ⌹ | |
| Alt | ⋄ | ¨ | ¯ | < | ≤ | ∅ | ≥ | > | ≠ | ∨ | ∧ | × | ÷ | |
| Shift | ~ | ! | @ | # | $ | % | ^ | & | * | ( | ) | _ | + | |
| Key | ` | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 | - | = | |
| Alt+Shift | ⍷ | √ | ⍨ | ⍸ | ⍥ | ⍣ | ⍞ | ⍬ | ⊣ | |||||
| Alt | ? | ⍵ | ∊ | ⍴ | § | ↑ | ↓ | ⍳ | ○ | π | ← | → | ⊢ | |
| Shift | Q | W | E | R | T | Y | U | I | O | P | { | } | | | |
| Key | q | w | e | r | t | y | u | i | o | p | [ | ] | \ | |
| Alt+Shift | ∫ | ∂ | ⌻ | ⍢ | ⍙ | ⍤ | ⍫ | ⌷ | ||||||
| Alt | ⍺ | ⌈ | ⌊ | ∞ | ∇ | ∆ | ∘ | ‼ | ⎕ | ⍎ | ⍕ | |||
| Shift | A | S | D | F | G | H | J | K | L | : | " | |||
| Key | a | s | d | f | g | h | j | k | l | ; | ' | |||
| Alt+Shift | ⊆ | ⊇ | χ | ⍡ | ⍭ | ⊙ | ||||||||
| Alt | ⊂ | ⊃ | ∩ | ∪ | ⊥ | ⊤ | ⍦ | ⍝ | ⍀ | ⌿ | ||||
| Shift | 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 | ||||||||||||||||
[[Category:Mouse Group {{{1}}}|{{{2}}}]]
