pegged.examples.pattern

This module is an attempt at introducing pattern-matching in D.

Pattern matching is a type- or value-matching present in functional languages like ML or Haskell.

The goal here is to obtain code like:

Pattern!"[ a, b, ... ]" p1; // match any range with at least two elements
                            // the rest being discarded.

auto m1 = p1([0,1,2,3,4]); // match and associate 'a' and 'b' with O and 1.
assert(m1.a == 0 && m1.b == 1);
auto m2 = p1("abc");
assert(m2.a = 'a' && m2.b == 'b');
auto m3 = p1(tuple("abc",0)); // not a range, the pattern fails
assert(m3 == matchFailure; // predefined constant

Pattern!"Tuple!(.,.) t" p2; // match any std.typecons.Tuple with two elements, of any type
auto m4 = p2(tuple("abc",0));
assert(m4.t = tuple("abc",0); // only the global pattern is named, and hence captured
assert(p2(tuple("abc")) == matchFailure); // only one member -> failure
assert(p2(tuple("abc",0,1)) == matchFailure); // three members -> failure (the pattern has no trailing ...

Pattern!" . { int, double, double }" p3; // match any aggregate (struct, class)
                                         // with three members being int,double and double, in that order.

Don't salivate, it's not implemented yet.

Members

Functions

anyValue auto anyValue(Args args): Undocumented in source. Be warned that the author may not have intended to support it.
endValue auto endValue(Args args): Undocumented in source. Be warned that the author may not have intended to support it.
failure auto failure(R rest): Undocumented in source. Be warned that the author may not have intended to support it.
rangeAny Tuple!(ElementType!R, R) rangeAny(R r): Undocumented in source. Be warned that the author may not have intended to support it.
rangeRest Tuple!(R, R) rangeRest(R r): Undocumented in source. Be warned that the author may not have intended to support it.
success Success!(M) success(M match, size_t begin, size_t end): Undocumented in source. Be warned that the author may not have intended to support it.

Structs

MatchResult struct MatchResult(size_t junction, T...): Undocumented in source.
Success struct Success(M...): Undocumented in source.
TypeAnd struct TypeAnd(alias Pattern1, alias Pattern2): Undocumented in source.
TypeAny struct TypeAny: Undocumented in source.
TypeDiscardMatch struct TypeDiscardMatch(alias Pattern): Discards the matched types, but propagate the indices.
TypeEnd struct TypeEnd: Undocumented in source.
TypeEps struct TypeEps: Undocumented in source.
TypeLiteral struct TypeLiteral(U...): Undocumented in source.
TypeNegLookAhead struct TypeNegLookAhead(alias Pattern): Undocumented in source.
TypeOneOrMore struct TypeOneOrMore(alias Pattern): Undocumented in source.
TypeOption struct TypeOption(alias Pattern): Undocumented in source.
TypeOr struct TypeOr(alias Pattern1, alias Pattern2): Undocumented in source.
TypePosLookAhead struct TypePosLookAhead(alias Pattern): Undocumented in source.
TypeSatisfy struct TypeSatisfy(alias test): Undocumented in source.
TypeSubType struct TypeSubType(U...): Undocumented in source.
TypeZeroOrMore struct TypeZeroOrMore(alias Pattern): Undocumented in source.
isRange struct isRange: Undocumented in source.

Templates

RangePatternResult template RangePatternResult(R): Undocumented in source.
TypeAnd template TypeAnd(Patterns...): Undocumented in source.
TypeAnd template TypeAnd(Patterns...): Undocumented in source.
TypeFailure template TypeFailure(T...): Undocumented in source.
TypeOr template TypeOr(Patterns...): Undocumented in source.
TypeOr template TypeOr(Patterns...): Undocumented in source.
isSubtype template isSubtype(T...): Undocumented in source.
onRange template onRange(RangePatterns...): Undocumented in source.

pegged.examples.pattern

Members

Functions

Structs

Templates

Meta

Source