Mathematica: Webel ADT pseudo classes: POLICY: Definer functions MUST return the self-declared or injected 'pattern' that determines the unique "ADT-signature" of the defined ADT class.

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Note kind
POLICY
Policy level
STRICT
Webel Mathematica keywords
ADT`
Webel ADT
ADT definer function
Keywords

This POLICY supports:

Mathematica: Webel ADT pseudo classes: DEFINITION/CONVENTION: Functions that populate ADTs with reusable ADT-method UpValues are called 'definers' and include '$def' in the name after a Package scope indicator: Example: adt$def$ADT, my$def$MY$CleverList

Using the universal base ADT definer as an example:


adt$def$ADT[
  class_Symbol,
  $usage_String,
  pattern_,
  isAllSuper:(True|False):False
] := Module[{ ...},
...
  class /: get[pattern] := $$;
  class /: head[pattern] := Head[$$];
...
  pattern
];


adt$def$ADT[MY$ADT$String,
  "An ADT that carries a String",
  MY$ADT$String[$$_String],
  True
]

MY$ADT$String[$$_String]
The unique defining ADT-signature of the ADT pseudo class MY$ADT$String is MY$ADT$String[$$_String].
Relates to
Mathematica: POLICY NOTES for the Webel Abstract Data Type (ADT) pseudo classes with inheritance for the Wolfram Language
Classes in the ADT` package: Extendable ADT pseudo classes have corresponding "definer functions"
Creating new ADTs that extend other classes using a definer function (and adt$addSuper)
Related notes
[CONVENTION, NAMING, POLICY]{STRONG} Mathematica: Webel ADT pseudo classes: DEFINITION/CONVENTION: Functions that populate ADTs with reusable ADT-method UpValues are called 'definers' and include '$def' in the name after a Package scope indicator: Example: adt$def$ADT, my$def$MY$CleverList
[CONVENTION, POLICY]{STRICT} Mathematica: Webel ADT pseudo classes: POLICY: Every named concrete Abstract Data Type (ADT) has a ONE unique "signature" (which is the pattern passed to the "definer" functions). To vary a signature, define another unique ADT name.
[CONVENTION, POLICY]{STRICT} Mathematica: Webel ADT pseudo classes: POLICY: The Abstract Data Types (ADTs) are stateless functional (although inheritance and overrides are supported), with no caching by default (although there is nice optional caching using CreateUUID[] and Once[]).
[POLICY]{STRICT} Mathematica: Webel ADT pseudo classes: POLICY: The expression '$$' is reserved as the primary named parameter for the defining pattern of all ADT classes that extend the universal base 'ADT' class.
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