PhraseBook: TechnicalReference

For a fuller explanation of complex issues such as Examples and Test Cases the StyleGuidelines is a good place to start.

Phrases

Users of unicode enabled interpreters should be able to cut & paste the code from the phrase pages into their session or functions (but see Apl2Problems).

Others such as APL+WIN users can manually copy it.

Main Phrases

• Phrases are single expressions with no statement separators ⋄ or newlines.

• Phrases should return the desired result rather than creating a side-effect on an existing array.
• Phrases should work on as many different platforms as possible.

• Phrases should be ⎕IO=0 compatible (and preferably also ⎕IO=1) if possible and unless otherwise stated.

• Phrases should be ISO/IEC 13751 (Extended APL Standard) compatible if possible and unless otherwise stated.
• Phrases should be APL2 compatible if possible and unless otherwise stated.

• Identifiers in phrases should follow the scheme in the NamingConventions table below or be assigned from them in a following comment: X...Y...Z   ⍝ X←B0; Y←C1; Z←I2

Specialities

• Incompatible phrases (as implied above and enumerated below) should be relegated to the Specialities section of the page keeping the head-line position for a compatible phrase.

• Phrases within this section should be headed (level three) with the dialects which support them and annotated with the required system settings (⎕IO ⎕ML ⎕CT &c.).

Incompatibilities (to be avoided in main phrases)

• ⍬ (empty numeric vector) is not implemented in APL2 - use (⍳0) or '' when type is not critical.

• Monadic ↓ - split is only implemented in Dyalog - use ⊂[0⊥⍳⍴⍴an]an enclose last axis.

• First is ↑ and Mix is ⊃ in APL2 and compatibles.

• First is ⊃ and Mix is ↑ in Dyalog with ⎕ML≤1.

• Dyadic ⊂ - partition splits at negative greater-than difference in an integer mask with zero masking in APL2 and compatiblesas Partition; and splits at ones in a boolean mask with leading zero masking in Dyalog with ⎕ML<3. as Partitioned enclose.

• ⎕FX requires a character matrix in APL+WIN as opposed to that or a nested list elsewhere.

• Neither '' nor (⍳0) is a valid argument to reshape of an empty array except in Dyalog.

• ⎕AI is not implemented in NARS2000.

Conforming Variants

• Alternative algorithms to the main phrase, perhaps with more annotated dependencies, that still conform to the constraints applied to main phrases, particularly in being interpreter independent.
• Reasons to include a variant:
  • works for a larger domain;
  • works along or across a different axis or dimension;
  • works with a different rank;
  • works at a different depth;
  • is faster in particular circumstances;
  • is capable of handling larger arrays.

NamingConventions

Insert Start - don't touch this: it's needed by RegEx expression in order to include the table underneath

so far: Bool, Int, Float, Num, Char, Enclosed, enclosed Text, Simple, Any Insert End - don't touch this: it's needed by RegEx expression in order to include the table above see GlossaryOfAplTerms for any of the above terms you don't understand.

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CategoryPhraseBookBackground