- Dr. Alistair Ward
Permits Perl-style shortcuts to be canned & assigned a single-
Char mnemonic for subsequent reference;
the implementation of
Read looks for a back-slashed
Char, for which it expects there to be a corresponding canned
Since the underlying polymorphic data-type isn't required to implement neither
Ord, the implementation of
Read can't cope with range-specifications.
Lacking this, Bracket-expression members must be enumerated exhaustively.
- The interface via which Perl-style shortcuts are expanded (when they occur within a bracket-expression), in a manner appropriate to the chosen type-parameter.
- The expansion of Perl-style shortcuts, is more restricted inside than outside, a bracket-expression,
& consequently are merely represented here by a
ShowablePredicate, rather than providing a more general form suitable also for those Perl-style shortcuts found outside bracket-expressions.
- This interface is implemented elsewhere, where the specific type-parameter & consequently the appropriate set of Perl-style shortcuts, are defined.
- A BracketExpression can contain either a literal, a range of literals given
(Enum a, Ord a), a Perl-style shortcut, or when
Charis the type-parameter, a POSIX Character-class.
- This data-type reduces the representation of all these possibilities to either a predicate or a literal.
|Predicate (ShowablePredicate m)|