Webel: Mathematica: CONVENTION: A 'type$' indicator for an '$opt$' or '$arg$' is for documentation only. It may use a "pattern helper", a human-friendly String, or a SysML-similar short-hand type representation. It need not correspond to a valid Pattern.
Webel: Mathematica: CONVENTION: A '$t$' prefix indicates a String help holder with a "pseudo type" indicator (for human friendly documentation only). Used by the Doc`, HelpF`, and HelpO` packages.
Webel: Mathematica: A help Rule 'rule$opt$' for an '$opt$' (option) accepts keys: '$k$help' (required), '$k$def' (required), and optional '$k$warn', '$k$tip', '$k$lab' (a label), '$k$type' (indicator only), '$k$mult' (SysML multiplicity), and '$k$pat'.
Webel: Mathematica: A help Rule 'rule$arg' for an '$arg$' (argument) accepts keys: '$k$help' (required), '$k$def' (required if $k$req = True not given), '$k$req' (True if $k$def not given), '$k$warn', '$k$tip', '$k$lab', '$k$type', '$k$mult' and '$k$pat'
Webel: Mathematica: CONVENTION: An '$opt$' (option) or '$arg$ (argument) help holder may be have an associated (typically short) '$lab$opt$' or '$lab$arg$' label help holder for use in GUIs and views.
Webel: Mathematica: CONVENTION: Where keys of Associations are Strings they are encapsulated as variables prefixed with '$k$' (promotes DRY and has many advantages, such as IDE prompting). Direct use of "Strings" as keys is WET and strongly discouraged!
Webel: Mathematica: CONVENTION: "pattern helpers" (which are not themselves Patterns) use the prefix '$pat$. Encapsulated Patterns use a 'pat$' prefix, and may use a '$pat$' pattern helper (such as an Alternatives).
Webel: Mathematica: CONVENTION: Argument help holders use a String variable with the prefix '$arg$', a related '$info$arg$' String, a 'def$arg$' default value expression and/or 'req$arg$', and optional '$warn$arg$', '$tip$arg$, '$lab$arg$', 'type$arg$'..
Webel: Psy/MPsy: Psychrometrics for Mathematica: Convention: Option variable names are prefixed with '$opt$psy'
Webel: Mathematica: CONVENTION: Option help holders use a String variable with the prefix '$opt$', a related '$info$opt$' String, a 'def$opt$' default value expression, and optional '$warn$opt$', '$tip$opt$', '$lab$opt$', and 'type$opt$' indicator ...