148 changes: 1 addition & 147 deletions std/experimental/allocator/common.d
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Original file line number Diff line number Diff line change
Expand Up @@ -8,153 +8,6 @@ Authors: $(WEB erdani.com, Andrei Alexandrescu), Timon Gehr (`Ternary`)
module std.experimental.allocator.common;
import std.algorithm, std.traits;

/**
Ternary type with three thruth values.
*/
struct Ternary
{
@safe @nogc nothrow pure:

package ubyte value = 6;
package static Ternary make(ubyte b)
{
Ternary r = void;
r.value = b;
return r;
}

/**
In addition to `false` and `true`, `Ternary` offers `unknown`.
*/
enum no = make(0);
/// ditto
enum yes = make(2);
/// ditto
enum unknown = make(6);

/**
Construct and assign from a `bool`, receiving `no` for `false` and `yes`
for `true`.
*/
this(bool b) { value = b << 1; }

/// ditto
void opAssign(bool b) { value = b << 1; }

/**
Construct a ternary value from another ternary value
*/
this(const Ternary b) { value = b.value; }

/**
$(TABLE Truth table for logical operations,
$(TR $(TH `a`) $(TH `b`) $(TH `$(TILDE)a`) $(TH `a | b`) $(TH `a & b`) $(TH `a ^ b`))
$(TR $(TD `no`) $(TD `no`) $(TD `yes`) $(TD `no`) $(TD `no`) $(TD `no`))
$(TR $(TD `no`) $(TD `yes`) $(TD) $(TD `yes`) $(TD `no`) $(TD `yes`))
$(TR $(TD `no`) $(TD `unknown`) $(TD) $(TD `unknown`) $(TD `no`) $(TD `unknown`))
$(TR $(TD `yes`) $(TD `no`) $(TD `no`) $(TD `yes`) $(TD `no`) $(TD `yes`))
$(TR $(TD `yes`) $(TD `yes`) $(TD) $(TD `yes`) $(TD `yes`) $(TD `no`))
$(TR $(TD `yes`) $(TD `unknown`) $(TD) $(TD `yes`) $(TD `unknown`) $(TD `unknown`))
$(TR $(TD `unknown`) $(TD `no`) $(TD `unknown`) $(TD `unknown`) $(TD `no`) $(TD `unknown`))
$(TR $(TD `unknown`) $(TD `yes`) $(TD) $(TD `yes`) $(TD `unknown`) $(TD `unknown`))
$(TR $(TD `unknown`) $(TD `unknown`) $(TD) $(TD `unknown`) $(TD `unknown`) $(TD `unknown`))
)
*/
Ternary opUnary(string s)() if (s == "~")
{
return make(386 >> value & 6);
}

/// ditto
Ternary opBinary(string s)(Ternary rhs) if (s == "|")
{
return make(25_512 >> value + rhs.value & 6);
}

/// ditto
Ternary opBinary(string s)(Ternary rhs) if (s == "&")
{
return make(26_144 >> value + rhs.value & 6);
}

/// ditto
Ternary opBinary(string s)(Ternary rhs) if (s == "^")
{
return make(26_504 >> value + rhs.value & 6);
}
}

@safe @nogc nothrow pure
unittest
{
alias f = Ternary.no, t = Ternary.yes, u = Ternary.unknown;
Ternary[27] truthTableAnd =
[
t, t, t,
t, u, u,
t, f, f,
u, t, u,
u, u, u,
u, f, f,
f, t, f,
f, u, f,
f, f, f,
];

Ternary[27] truthTableOr =
[
t, t, t,
t, u, t,
t, f, t,
u, t, t,
u, u, u,
u, f, u,
f, t, t,
f, u, u,
f, f, f,
];

Ternary[27] truthTableXor =
[
t, t, f,
t, u, u,
t, f, t,
u, t, u,
u, u, u,
u, f, u,
f, t, t,
f, u, u,
f, f, f,
];

for (auto i = 0; i != truthTableAnd.length; i += 3)
{
assert((truthTableAnd[i] & truthTableAnd[i + 1])
== truthTableAnd[i + 2]);
assert((truthTableOr[i] | truthTableOr[i + 1])
== truthTableOr[i + 2]);
assert((truthTableXor[i] ^ truthTableXor[i + 1])
== truthTableXor[i + 2]);
}

Ternary a;
assert(a == Ternary.unknown);
static assert(!is(typeof({ if (a) {} })));
assert(!is(typeof({ auto b = Ternary(3); })));
a = true;
assert(a == Ternary.yes);
a = false;
assert(a == Ternary.no);
a = Ternary.unknown;
assert(a == Ternary.unknown);
Ternary b;
b = a;
assert(b == a);
assert(~Ternary.yes == Ternary.no);
assert(~Ternary.no == Ternary.yes);
assert(~Ternary.unknown == Ternary.unknown);
}

/**
Returns the size in bytes of the state that needs to be allocated to hold an
object of type $(D T). $(D stateSize!T) is zero for $(D struct)s that are not
Expand Down Expand Up @@ -605,6 +458,7 @@ package void testAllocator(alias make)()
{
import std.conv : text;
import std.stdio : writeln, stderr;
import std.typecons : Ternary;
alias A = typeof(make());
scope(failure) stderr.writeln("testAllocator failed for ", A.stringof);

Expand Down
171 changes: 171 additions & 0 deletions std/typecons.d
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Original file line number Diff line number Diff line change
Expand Up @@ -7143,3 +7143,174 @@ unittest
ubyte, ubyte, T3, T3,
);
}

/**
Ternary type with three truth values:
$(UL
$(LI `Ternary.yes` for `true`)
$(LI `Ternary.no` for `false`)
$(LI `Ternary.unknown` as an unknown state)
)
Also known as trinary, trivalent, or trilean.
See_Also:
$(WEB https://en.wikipedia.org/wiki/Three-valued_logic,
Three Valued Logic on Wikipedia)
*/
struct Ternary
{
@safe @nogc nothrow pure:

private ubyte value = 6;
private static Ternary make(ubyte b)
{
Ternary r = void;
r.value = b;
return r;
}

/**
The possible states of the `Ternary`
*/
enum no = make(0);
/// ditto
enum yes = make(2);
/// ditto
enum unknown = make(6);

/**
Construct and assign from a `bool`, receiving `no` for `false` and `yes`
for `true`.
*/
this(bool b) { value = b << 1; }

/// ditto
void opAssign(bool b) { value = b << 1; }

/**
Construct a ternary value from another ternary value
*/
this(const Ternary b) { value = b.value; }

/**
$(TABLE Truth table for logical operations,
$(TR $(TH `a`) $(TH `b`) $(TH `$(TILDE)a`) $(TH `a | b`) $(TH `a & b`) $(TH `a ^ b`))
$(TR $(TD `no`) $(TD `no`) $(TD `yes`) $(TD `no`) $(TD `no`) $(TD `no`))
$(TR $(TD `no`) $(TD `yes`) $(TD) $(TD `yes`) $(TD `no`) $(TD `yes`))
$(TR $(TD `no`) $(TD `unknown`) $(TD) $(TD `unknown`) $(TD `no`) $(TD `unknown`))
$(TR $(TD `yes`) $(TD `no`) $(TD `no`) $(TD `yes`) $(TD `no`) $(TD `yes`))
$(TR $(TD `yes`) $(TD `yes`) $(TD) $(TD `yes`) $(TD `yes`) $(TD `no`))
$(TR $(TD `yes`) $(TD `unknown`) $(TD) $(TD `yes`) $(TD `unknown`) $(TD `unknown`))
$(TR $(TD `unknown`) $(TD `no`) $(TD `unknown`) $(TD `unknown`) $(TD `no`) $(TD `unknown`))
$(TR $(TD `unknown`) $(TD `yes`) $(TD) $(TD `yes`) $(TD `unknown`) $(TD `unknown`))
$(TR $(TD `unknown`) $(TD `unknown`) $(TD) $(TD `unknown`) $(TD `unknown`) $(TD `unknown`))
)
*/
Ternary opUnary(string s)() if (s == "~")
{
return make((386 >> value) & 6);
}

/// ditto
Ternary opBinary(string s)(Ternary rhs) if (s == "|")
{
return make((25_512 >> (value + rhs.value)) & 6);
}

/// ditto
Ternary opBinary(string s)(Ternary rhs) if (s == "&")
{
return make((26_144 >> (value + rhs.value)) & 6);
}

/// ditto
Ternary opBinary(string s)(Ternary rhs) if (s == "^")
{
return make((26_504 >> (value + rhs.value)) & 6);
}
}

///
@safe @nogc nothrow pure
unittest
{
Ternary a;
assert(a == Ternary.unknown);

assert(~Ternary.yes == Ternary.no);
assert(~Ternary.no == Ternary.yes);
assert(~Ternary.unknown == Ternary.unknown);
}

@safe @nogc nothrow pure
unittest
{
alias f = Ternary.no, t = Ternary.yes, u = Ternary.unknown;
Ternary[27] truthTableAnd =
[
t, t, t,
t, u, u,
t, f, f,
u, t, u,
u, u, u,
u, f, f,
f, t, f,
f, u, f,
f, f, f,
];

Ternary[27] truthTableOr =
[
t, t, t,
t, u, t,
t, f, t,
u, t, t,
u, u, u,
u, f, u,
f, t, t,
f, u, u,
f, f, f,
];

Ternary[27] truthTableXor =
[
t, t, f,
t, u, u,
t, f, t,
u, t, u,
u, u, u,
u, f, u,
f, t, t,
f, u, u,
f, f, f,
];

for (auto i = 0; i != truthTableAnd.length; i += 3)
{
assert((truthTableAnd[i] & truthTableAnd[i + 1])
== truthTableAnd[i + 2]);
assert((truthTableOr[i] | truthTableOr[i + 1])
== truthTableOr[i + 2]);
assert((truthTableXor[i] ^ truthTableXor[i + 1])
== truthTableXor[i + 2]);
}

Ternary a;
assert(a == Ternary.unknown);
static assert(!is(typeof({ if (a) {} })));
assert(!is(typeof({ auto b = Ternary(3); })));
a = true;
assert(a == Ternary.yes);
a = false;
assert(a == Ternary.no);
a = Ternary.unknown;
assert(a == Ternary.unknown);
Ternary b;
b = a;
assert(b == a);
assert(~Ternary.yes == Ternary.no);
assert(~Ternary.no == Ternary.yes);
assert(~Ternary.unknown == Ternary.unknown);
}