Merge pull request #5 from Abscissa/master

Document basic usage.
This commit is contained in:
Sönke Ludwig 2016-09-20 08:30:02 +02:00 committed by GitHub
commit 2d9f9c537f
2 changed files with 130 additions and 1 deletions

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@ -3,4 +3,69 @@ TaggedAlgebraic
Implementation of a generic algebraic data type with a tagged union storage. All operations of the contained types are available for the `TaggedAlgebraic`
[![Build Status](https://travis-ci.org/s-ludwig/taggedalgebraic.svg?branch=master)](https://travis-ci.org/s-ludwig/taggedalgebraic) [![Coverage Status](https://coveralls.io/repos/s-ludwig/taggedalgebraic/badge.png?branch=master)](https://coveralls.io/r/s-ludwig/taggedalgebraic?branch=master)
[![Build Status](https://travis-ci.org/s-ludwig/taggedalgebraic.svg?branch=master)](https://travis-ci.org/s-ludwig/taggedalgebraic) [![Coverage Status](https://coveralls.io/repos/s-ludwig/taggedalgebraic/badge.png?branch=master)](https://coveralls.io/r/s-ludwig/taggedalgebraic?branch=master)
Usage
-----
```d
import taggedalgebraic;
struct Foo {
string name;
void bar() {}
}
union Base {
int i;
string str;
Foo foo;
}
alias Tagged = TaggedAlgebraic!Base;
// Instantiate
Tagged taggedInt = 5;
Tagged taggedString = "Hello";
Tagged taggedFoo = Foo();
Tagged taggedAny = taggedInt;
taggedAny = taggedString;
taggedAny = taggedFoo;
// Check type: Tagged.Kind is an enum
assert(taggedInt.kind == Tagged.Kind.i);
assert(taggedString.kind == Tagged.Kind.str);
assert(taggedFoo.kind == Tagged.Kind.foo);
assert(taggedAny.kind == Tagged.Kind.foo);
// In most cases, can simply use as-is
auto num = 4 + taggedInt;
auto msg = taggedString ~ " World!";
taggedFoo.bar();
if (taggedAny.kind == Tagged.Kind.foo) // Make sure to check type first!
taggedAny.bar();
//taggedString.bar(); // AssertError: Not a Foo!
// Convert back by casting
auto i = cast(int) taggedInt;
auto str = cast(string) taggedString;
auto foo = cast(Foo) taggedFoo;
if (taggedAny.kind == Tagged.Kind.foo) // Make sure to check type first!
auto foo2 = cast(Foo) taggedAny;
//cast(Foo) taggedString; // AssertError!
// Kind is an enum, so final switch is supported:
final switch (taggedAny.kind) {
case Tagged.Kind.i:
// It's "int i"
break;
case Tagged.Kind.str:
// It's "string str"
break;
case Tagged.Kind.foo:
// It's "Foo foo"
break;
}
```

View file

@ -195,6 +195,70 @@ struct TaggedAlgebraic(U) if (is(U == union) || is(U == struct))
private @trusted @property ref inout(T) trustedGet(T)() inout { return *cast(inout(T)*)m_data.ptr; }
}
///
unittest
{
import taggedalgebraic;
struct Foo {
string name;
void bar() {}
}
union Base {
int i;
string str;
Foo foo;
}
alias Tagged = TaggedAlgebraic!Base;
// Instantiate
Tagged taggedInt = 5;
Tagged taggedString = "Hello";
Tagged taggedFoo = Foo();
Tagged taggedAny = taggedInt;
taggedAny = taggedString;
taggedAny = taggedFoo;
// Check type: Tagged.Kind is an enum
assert(taggedInt.kind == Tagged.Kind.i);
assert(taggedString.kind == Tagged.Kind.str);
assert(taggedFoo.kind == Tagged.Kind.foo);
assert(taggedAny.kind == Tagged.Kind.foo);
// In most cases, can simply use as-is
auto num = 4 + taggedInt;
auto msg = taggedString ~ " World!";
taggedFoo.bar();
if (taggedAny.kind == Tagged.Kind.foo) // Make sure to check type first!
taggedAny.bar();
//taggedString.bar(); // AssertError: Not a Foo!
// Convert back by casting
auto i = cast(int) taggedInt;
auto str = cast(string) taggedString;
auto foo = cast(Foo) taggedFoo;
if (taggedAny.kind == Tagged.Kind.foo) // Make sure to check type first!
auto foo2 = cast(Foo) taggedAny;
//cast(Foo) taggedString; // AssertError!
// Kind is an enum, so final switch is supported:
final switch (taggedAny.kind) {
case Tagged.Kind.i:
// It's "int i"
break;
case Tagged.Kind.str:
// It's "string str"
break;
case Tagged.Kind.foo:
// It's "Foo foo"
break;
}
}
/** Operators and methods of the contained type can be used transparently.
*/
@safe unittest {