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Merged
JackStouffer merged 1 commit into from
Jan 4, 2017
Merged

std.traits: hasFunctionAttributes #4287

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47 changes: 36 additions & 11 deletions changelog.dd
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Original file line number Diff line number Diff line change
Expand Up @@ -10,13 +10,14 @@ $(BUGSTITLE Library Changes,
in multi-term arithmetic expressions.))
$(LI $(RELATIVE_LINK2 staticIsSorted, Added `std.meta.staticIsSorted` to check if
an `AliasSeq` is sorted according to some template predicate.))
$(LI $(RELATIVE_LINK2 minIndex, Added `std.algorithm.searching.minIndex`
to get the index of the minimum element of a range.))
$(LI $(RELATIVE_LINK2 maxIndex, Added `std.algorithm.searching.maxIndex`
to get the index of the maximum element of a range.))
$(LI $(RELATIVE_LINK2 ndslice-removal, `std.experimental.ndslice`
has been deprecated.))

$(LI $(RELATIVE_LINK2 minIndex, Added `std.algorithm.searching.minIndex`
to get the index of the minimum element of a range.))
$(LI $(RELATIVE_LINK2 maxIndex, Added `std.algorithm.searching.maxIndex`
to get the index of the maximum element of a range.))
$(LI $(RELATIVE_LINK2 ndslice-removal, `std.experimental.ndslice`
has been deprecated.))
$(LI $(RELATIVE_LINK2 has-function-attributes, Added `std.traits.hasFunctionAttributes`
as a user-friendly way to query for function attributes.))
)

$(BUGSTITLE Library Changes,
Expand Down Expand Up @@ -48,8 +49,8 @@ static assert(!staticIsSorted!(Comp, bool, long, dchar));
)

$(LI $(LNAME2 minIndex, `std.algorithm.searching.minIndex` gets the index of
the minimum element of a range, according to a specified predicate. The
default predicate is "a < b")
the minimum element of a range, according to a specified predicate. The
default predicate is "a < b")
-------
import std.algorithm.searching : minIndex;
int[] a = [5, 4, 2, 1, 9, 10];
Expand All @@ -61,8 +62,8 @@ assert(a.minIndex == -1);
)

$(LI $(LNAME2 maxIndex, `std.algorithm.searching.maxIndex` gets the index of
the maximum element of a range, according to a specified predicate. The
default predicate is "a > b")
the maximum element of a range, according to a specified predicate. The
default predicate is "a > b")
-------
import std.algorithm.searching : maxIndex;
int[] a = [5, 4, 2, 1, 9, 10];
Expand All @@ -81,6 +82,30 @@ deprecated.)
mir package).
)

$(LI $(LNAME2 has-function-attributes, `std.traits.hasFunctionAttributes` has
been added)
It exposes a user-friendly way to query for function attributes:
-------
import std.traits : hasFunctionAttributes;

// manually annotated function
real func(real x) pure nothrow @safe
{
return x;
}
static assert(hasFunctionAttributes!(func, "@safe", "pure"));
static assert(!hasFunctionAttributes!(func, "@trusted"));

// for templated function types are automatically inferred
bool myFunc(T)(T b)
{
return !b;
}
static assert(hasFunctionAttributes!(myFunc!bool, "@safe", "pure", "@nogc", "nothrow"));
static assert(!hasFunctionAttributes!(myFunc!bool, "shared"));
-------
)

)

Macros:
Expand Down
197 changes: 197 additions & 0 deletions std/traits.d
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
* $(LREF isFunction)
* $(LREF arity)
* $(LREF functionAttributes)
* $(LREF hasFunctionAttributes)
* $(LREF functionLinkage)
* $(LREF FunctionTypeOf)
* $(LREF isSafe)
Expand Down Expand Up @@ -1308,6 +1309,9 @@ alias ParameterDefaultValueTuple = ParameterDefaults;

/**
Returns the attributes attached to a function $(D func).

See_Also:
$(LREF hasFunctionAttributes)
*/
enum FunctionAttribute : uint
{
Expand Down Expand Up @@ -1495,6 +1499,199 @@ private FunctionAttribute extractAttribFlags(Attribs...)()
return res;
}

/**
Checks whether a function has the given attributes attached.

Params:
func = function to check
attributes = variadic number of function attributes as strings

Returns:
`true`, if the function has the list of attributes attached and `false` otherwise.

See_Also:
$(LREF functionAttributes)
*/
template hasFunctionAttributes(args...)
if (isCallable!(args[0]) && args.length > 0
&& allSatisfy!(isSomeString, typeof(args[1 .. $])))
{
enum bool hasFunctionAttributes = {
import std.algorithm.searching : canFind;
import std.range : only;
enum funcAttribs = only(__traits(getFunctionAttributes, args[0]));
foreach (attribute; args[1 .. $])
{
if (!funcAttribs.canFind(attribute))
return false;
}
return true;
}();
}

///
unittest
{
real func(real x) pure nothrow @safe;
static assert(hasFunctionAttributes!(func, "@safe", "pure"));
static assert(!hasFunctionAttributes!(func, "@trusted"));

// for templates types are automatically inferred
bool myFunc(T)(T b)
{
return !b;
}
static assert(hasFunctionAttributes!(myFunc!bool, "@safe", "pure", "@nogc", "nothrow"));
static assert(!hasFunctionAttributes!(myFunc!bool, "shared"));
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@wilzbach wilzbach Jan 4, 2017

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This change is just to make the public unittest a bit more interesting and not use @trusted twice.

}

unittest
{
struct S
{
int noF();
int constF() const;
int immutableF() immutable;
int inoutF() inout;
int sharedF() shared;

ref int refF() return;
int propertyF() @property;
int nothrowF() nothrow;
int nogcF() @nogc;

int systemF() @system;
int trustedF() @trusted;
int safeF() @safe;

int pureF() pure;
}
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@wilzbach wilzbach Aug 31, 2016

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CodeCov is failing because DMD counts all these functions as uncovered.
(there's a NG thread discussion about not counting unittest blocks, but tl:dr it won't happen)


// true if no args passed
static assert(hasFunctionAttributes!(S.noF));

static assert(hasFunctionAttributes!(S.noF, "@system"));
static assert(hasFunctionAttributes!(typeof(S.noF), "@system"));
static assert(!hasFunctionAttributes!(S.noF, "@system", "pure"));

static assert(hasFunctionAttributes!(S.constF, "const", "@system"));
static assert(hasFunctionAttributes!(typeof(S.constF), "const", "@system"));
static assert(!hasFunctionAttributes!(S.constF, "const", "@system", "@nogc"));

static assert(hasFunctionAttributes!(S.immutableF, "immutable", "@system"));
static assert(hasFunctionAttributes!(typeof(S.immutableF), "immutable", "@system"));
static assert(!hasFunctionAttributes!(S.immutableF, "immutable", "@system", "pure"));

static assert(hasFunctionAttributes!(S.inoutF, "inout", "@system"));
static assert(hasFunctionAttributes!(typeof(S.inoutF), "inout", "@system"));
static assert(!hasFunctionAttributes!(S.inoutF, "inout", "@system", "pure"));

static assert(hasFunctionAttributes!(S.sharedF, "shared", "@system"));
static assert(hasFunctionAttributes!(typeof(S.sharedF), "shared", "@system"));
static assert(!hasFunctionAttributes!(S.sharedF, "shared", "@system", "@trusted"));

static assert(hasFunctionAttributes!(S.refF, "ref", "@system", "return"));
static assert(hasFunctionAttributes!(typeof(S.refF), "ref", "@system", "return"));
static assert(!hasFunctionAttributes!(S.refF, "ref", "@system", "return", "pure"));

static assert(hasFunctionAttributes!(S.propertyF, "@property", "@system"));
static assert(hasFunctionAttributes!(typeof(&S.propertyF), "@property", "@system"));
static assert(!hasFunctionAttributes!(S.propertyF, "@property", "@system", "ref"));

static assert(hasFunctionAttributes!(S.nothrowF, "nothrow", "@system"));
static assert(hasFunctionAttributes!(typeof(S.nothrowF), "nothrow", "@system"));
static assert(!hasFunctionAttributes!(S.nothrowF, "nothrow", "@system", "@trusted"));

static assert(hasFunctionAttributes!(S.nogcF, "@nogc", "@system"));
static assert(hasFunctionAttributes!(typeof(S.nogcF), "@nogc", "@system"));
static assert(!hasFunctionAttributes!(S.nogcF, "@nogc", "@system", "ref"));

static assert(hasFunctionAttributes!(S.systemF, "@system"));
static assert(hasFunctionAttributes!(typeof(S.systemF), "@system"));
static assert(!hasFunctionAttributes!(S.systemF, "@system", "ref"));

static assert(hasFunctionAttributes!(S.trustedF, "@trusted"));
static assert(hasFunctionAttributes!(typeof(S.trustedF), "@trusted"));
static assert(!hasFunctionAttributes!(S.trustedF, "@trusted", "@safe"));

static assert(hasFunctionAttributes!(S.safeF, "@safe"));
static assert(hasFunctionAttributes!(typeof(S.safeF), "@safe"));
static assert(!hasFunctionAttributes!(S.safeF, "@safe", "nothrow"));

static assert(hasFunctionAttributes!(S.pureF, "pure", "@system"));
static assert(hasFunctionAttributes!(typeof(S.pureF), "pure", "@system"));
static assert(!hasFunctionAttributes!(S.pureF, "pure", "@system", "ref"));

int pure_nothrow() nothrow pure { return 0; }
void safe_nothrow() @safe nothrow { }
static ref int static_ref_property() @property { return *(new int); }
ref int ref_property() @property { return *(new int); }

static assert(hasFunctionAttributes!(pure_nothrow, "pure", "nothrow", "@safe"));
static assert(hasFunctionAttributes!(typeof(pure_nothrow), "pure", "nothrow", "@safe"));
static assert(!hasFunctionAttributes!(pure_nothrow, "pure", "nothrow", "@safe", "@trusted"));

static assert(hasFunctionAttributes!(safe_nothrow, "@safe", "nothrow"));
static assert(hasFunctionAttributes!(typeof(safe_nothrow), "@safe", "nothrow"));
static assert(hasFunctionAttributes!(safe_nothrow, "@safe", "nothrow", "pure"));
static assert(!hasFunctionAttributes!(safe_nothrow, "@safe", "nothrow", "pure", "@trusted"));

static assert(hasFunctionAttributes!(static_ref_property, "@property", "ref", "@safe"));
static assert(hasFunctionAttributes!(typeof(&static_ref_property), "@property", "ref", "@safe"));
static assert(hasFunctionAttributes!(static_ref_property, "@property", "ref", "@safe", "nothrow"));
static assert(!hasFunctionAttributes!(static_ref_property, "@property", "ref", "@safe", "nothrow", "@nogc"));

static assert(hasFunctionAttributes!(ref_property, "@property", "ref", "@safe"));
static assert(hasFunctionAttributes!(typeof(&ref_property), "@property", "ref", "@safe"));
static assert(!hasFunctionAttributes!(ref_property, "@property", "ref", "@safe", "@nogc"));

struct S2
{
int pure_const() const pure { return 0; }
int pure_sharedconst() const shared pure { return 0; }
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@andralex andralex Jan 4, 2017

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these, too - declare and don't define

}

static assert(hasFunctionAttributes!(S2.pure_const, "const", "pure", "@system"));
static assert(hasFunctionAttributes!(typeof(S2.pure_const), "const", "pure", "@system"));
static assert(!hasFunctionAttributes!(S2.pure_const, "const", "pure", "@system", "ref"));

static assert(hasFunctionAttributes!(S2.pure_sharedconst, "const", "shared", "pure", "@system"));
static assert(hasFunctionAttributes!(typeof(S2.pure_sharedconst), "const", "shared", "pure", "@system"));
static assert(!hasFunctionAttributes!(S2.pure_sharedconst, "const", "shared", "pure", "@system", "@nogc"));

static assert(hasFunctionAttributes!((int a) { }, "pure", "nothrow", "@nogc", "@safe"));
static assert(hasFunctionAttributes!(typeof((int a) { }), "pure", "nothrow", "@nogc", "@safe"));
static assert(!hasFunctionAttributes!((int a) { }, "pure", "nothrow", "@nogc", "@safe", "ref"));

auto safeDel = delegate() @safe { };
static assert(hasFunctionAttributes!(safeDel, "pure", "nothrow", "@nogc", "@safe"));
static assert(hasFunctionAttributes!(typeof(safeDel), "pure", "nothrow", "@nogc", "@safe"));
static assert(!hasFunctionAttributes!(safeDel, "pure", "nothrow", "@nogc", "@safe", "@system"));

auto trustedDel = delegate() @trusted { };
static assert(hasFunctionAttributes!(trustedDel, "pure", "nothrow", "@nogc", "@trusted"));
static assert(hasFunctionAttributes!(typeof(trustedDel), "pure", "nothrow", "@nogc", "@trusted"));
static assert(!hasFunctionAttributes!(trustedDel, "pure", "nothrow", "@nogc", "@trusted", "ref"));

auto systemDel = delegate() @system { };
static assert(hasFunctionAttributes!(systemDel, "pure", "nothrow", "@nogc", "@system"));
static assert(hasFunctionAttributes!(typeof(systemDel), "pure", "nothrow", "@nogc", "@system"));
static assert(!hasFunctionAttributes!(systemDel, "pure", "nothrow", "@nogc", "@system", "@property"));


// call functions to make CodeCov happy
{
assert(pure_nothrow == 0);
safe_nothrow;
assert(static_ref_property == 0);
assert(ref_property == 0);
assert(S2().pure_const == 0);
assert((shared S2()).pure_sharedconst == 0);
cast(void) safeDel;
cast(void) trustedDel;
cast(void) systemDel;
}
}

/**
$(D true) if $(D func) is $(D @safe) or $(D @trusted).
Expand Down