D 2019-01-01T13:35:06.190
L Supplements
P 070fe6c95bff0aa7dc4ce8c7751c353d87772dc0d9b3321aa38bf86958f3cc52
U luismachuca
W 12680
<h1>Cxxomfort Library Supplements</h1>
The <code>cxxomfort</code> library offers some specific utilities of its own, not found in C++03 or C++11.
The header <code>cxxomfort/library.hpp></code> is responsible for adding these features, and automatically included when using <code>#include <cxxomfort/cxxomfort.hpp></code> as well. All the features thus included are defined in namespace <code>cxxomfort</code>.
Unlike [Extras], these features are considered intrinsic to the cxxomfort library: other features are allowed to depend on them, and they do not need to be explicitly included to work.
<b>General index of library utilities</b>:
* [#cxxo-sup-algorithm|Supplementals for <algorithm>]
* [#cxxo-sup-functional|Supplementals for <functional>]
* [#cxxo-sup-iterator|Supplementals for <iterator>]
* [#cxxo-sup-numeric|Supplementals for <numeric>]
* [#cxxo-sup-random|Supplementals for <random>]
* [#cxxo-sup-string|Supplementals for <string>]
* [#cxxo-sup-tuple|Supplementals for <tuple>]
* [#cxxo-sup-type_traits|Supplementals for <type_traits>]
* Array References
* [#foreach|Foreach Loop Emulation]
* <code>[#fixed_vector]</code>
* Initialization of sequences
* Local Function Emulation
* Sequence-related Utilities
* [#type_name|Type Identification utilities]
* [#typesafeenum|Typesafe Enums]
* <del>Upgraded <code>std::pair</code></del>
* <del>Upgraded <code>std::vector</code></del>
<a id="arrayref"></a>
<h2>Array References</h2>
<verbatim>
#include <cxxomfort/library/array_ref.hpp>
</verbatim>
The cxxomfort library implements n3334's <tt>array_ref<T></tt> as a Supplement: a reference or view-type for a contiguous sequence of elements. [http://ryan.gulix.cl/cxxomfort-docs/html/libarrayref.html|Generated Documentation].
<a id="foreach"></a>
<h2>Foreach Loop</h2>
<verbatim>
#include <cxxomfort/library/foreach.hpp>
</verbatim>
<b>[Features/Foreach|"foreach" Loop emulation]</b>: allows writing C++11-like foreach loops in C++03 via a reworked implementation of the Artima <em>Foreach</em> utility, which also generates native foreach loops in C++11 onwards, thus resulting in zero overhead.
<verbatim>
SomeSequence<string> mystrings;
// fill mystrings somehow
CXXO_FOREACH /string const& s, mystrings) {
// do stuff with 's'
}
</verbatim>
<a id="fixed_vector"></a>
<h2>Fixed_vector</h2>
<verbatim>
#include <cxxomfort/library/fixed_vector.hpp>
</verbatim>
<b>[Features/FixedVector|<code>fixed_vector<T></code>]</b> - the oft sought for holy grail of a <code>std::vector</code> whose size is fixed at construction as an invariant. [http://ryan.gulix.cl/cxxomfort-docs/html/liibfixedvector.html|Generated Documentation].
<verbatim>
fixed_vector<short> fixed(32);
// this vector has exactly 32 elements and can not be resized.
</verbatim>
<a id="i12n"></a>
<h2>Initialization of Sequence Containers</h2>
<verbatim>
#include <cxxomfort/library/i12n.hpp>
</verbatim>
<b>[Features/SequencesInitialization|Initialization of Sequences]</b>: a way to use a syntax similar to C++11's <code>{ , , , }</code> initialization of containers in various kinda of sequence-like containers, even in C++03.
<verbatim>
CXXO_I12N_SEQ (vector<string>, mystrings, { "foo", "bar", "baz" } );
// operate on mystrings
cout<< mystrings[1]<< endl; // foo
</verbatim>
<a id="localfun"></a>
<h2>Local Function Emulation</h2>
<verbatim>
#include <cxxomfort/library/localfn.hpp>
</verbatim>
<b>[Features/LocalFunction|Using local functions in template calls]</b>: a way to have locally defined functions or functors, which then can be used as arguments for eg.: STL algorithm calls. While one of the big limitations in C++03 is the inability to use <em>local types</em> as arguments to anything templated, this library adds a partial implementation that creates proxy functor objects, where the actual "calling" code resides out of scope, and that produces code near transpartent to C++11 onwards.
<verbatim>
// here, X is a tag that identifies the functor type in case one needs to add state or other nontrivial behaviour
CXXO_LOCALFN(X,void(int,int)) (int x0, int x1) {
std::cout<< '{'<< x0+1<< ','<< x1-1<< '}'<< std::endl;
}
CXXO_LOCALFN_NAME(X,mi_fn);
function<void(int,int)> f_localfn = mi_fn; // <-- can only exist in the current scope
CXXO_LOCALFN(Neg_,int(int)) (int x) {
return -x;
}
CXXO_LOCALFN_NAME(Neg_,negate);
transform( begin(sequence), end(sequence), begin(sequence), negate );
</verbatim>
<a id="type_name"></a>
<h2>Type Identification</h2>
<verbatim>
#include <cxxomfort/library/type_name.hpp>
</verbatim>
* <code>template <typename T><br/>std::string <b>type_name</b> ()</code> (1)
* <code>std::string <b>typeid_demangle</b> (std::type_info const&)</code> (2)
Given:
(1) a type T passed as a template argument;
(2) a function argument resulting from <em>typeid</em> evaluation;
these utilities return information from <code>typeid::name()</code>,
except this information is demangled if demangling is available.
<a id="typesafeenum"></a>
<h2>Typesafe Enums</h2>
<verbatim>
#include <cxxomfort/library/typesafe_enum.hpp>
</verbatim>
<b>[Features/typesafe_enum|<code>typesafe_enum<T,S></code>]</b> - a typesafe declaration wrapper for enum types, that implements the basic idea behind the <code>enum class...</code> feature of C++11.
<h2>Supplemental Headers</h2>
<a name="cxxo-sup-algorithm"></a>
<h3>Supplementals for <algorithm></h3>
<verbatim>
#include <cxxomfort/library/algorithm.hpp>
</verbatim>
Names made available: <tt>copy_leftmost_n, copy_rightmost_n, find_inversion, fix_inversion, valcmp, transform_inplace</tt>, etc.
[http://ryan.gulix.cl/cxxomfort-docs/html/cxxo-sup-algorithm.html|Listing of the functions and interfaces included in this supplement].
<a name="cxxo-sup-functional"></a>
<h3>Supplementals for <functional></h3>
<verbatim>
#include <cxxomfort/library/functional.hpp>
</verbatim>
[http://ryan.gulix.cl/cxxomfort-docs/html/cxxo-sup-functional.html|Listing of the functions and interfaces included in this supplement].
<b>Functional supplements to operator wrappers</b> - Just as there exists <code>std::plus</code> to wrap <code>operator+</code>, cxxomfort provides wrappers for the assignment version of those operators.
* <code>plus_it</code> - applies "<code>+=</code>" to its arguments.
* <code>minus_it</code> - applies "<code>-=</code>" to its arguments.
* <code>multiplies_it</code> - applies "<code>*=</code>" to its arguments.
* <code>divides_it</code> - applies "<code>/=</code>" to its arguments.
* <code>modulus_it</code> - applies "<code>%=</code>" to its arguments.
* <code>noop</code>, a simple do-nothing function object for completeness.
<b>Other features</b>
* <tt>functiontype</tt> - type traits for function signatures such as return type, arity, etc.
* <tt>function_ref</tt> from LLVM.
* <tt>function_caller</tt> - zero overhead functor for calling a named C function.
<a name="cxxo-sup-iterator"></a>
<h3>Supplementals for <iterator></h3>
<verbatim>
#include <cxxomfort/library/iterator.hpp>
namespace cxxomfort::library::iterator;
</verbatim>
Names made available: <tt>ssize , absdistance , fake_iterator</tt> etc.
[http://ryan.gulix.cl/cxxomfort-docs/html/cxxo-sup-iterator.html|Listing of the functions and interfaces included in this supplement].
<a name="cxxo-sup-numeric"></a>
<h3>Supplementals for <numeric></h3>
<verbatim>
#include <cxxomfort/library/numeric.hpp>
namespace cxxomfort::library::numeric;
</verbatim>
This header mostly provides static / compile time alternatives to <tt><numeric></tt>'s constexpr additions such as gcd and lcm, as well as a number of static / compile-time accumulators such as <tt>static_minmax</tt> and <tt>static_sum</tt>.
[http://ryan.gulix.cl/cxxomfort-docs/html/cxxo-sup-numeric.html|Listing of the functions and interfaces included in this supplement].
<a name="cxxo-sup-random"></a>
<h3>Supplementals for <random></h3>
<verbatim>
#include <cxxomfort/library/random.hpp>
namespace cxxomfort::library::random;
</verbatim>
* <tt>MMIX</tt>, <tt>numerical_recipes</tt> named typedefs for std linear engine.
* <tt>reseed</tt> and <tt>randint</tt> from Fundamentals V2.
* <tt>splitmix64</tt> PRNG.
<a name="cxxo-sup-string"></a>
<h3>Supplementals for <string></h3>
<verbatim>
#include <cxxomfort/library/string.hpp>
namespace cxxomfort::library::string;
</verbatim>
[http://ryan.gulix.cl/cxxomfort-docs/html/cxxo-sup-string.html|Listing of the functions and interfaces included in this supplement].
Features include:
* Generic <tt>to_string</tt> from p0117.
* Generic <tt>ltrim, rtrim</tt> functions.
* <tt>string_cast</tt>.
<a name="cxxo-sup-tuple"></a>
<h3>Supplementals for <tuple></h3>
<verbatim>
#include <cxxomfort/library/tuple.hpp>
</verbatim>
Features include:
* <code>is_tuple</code> - type trait to recognize a tuple.
* <code>tuple_pop</code> - creates a tuple with the last (rightmost) element removed.
* <code>tuple_shift</code> - creates a tuple with the first (leftmost) element removed (C++11 onwards only).
* <code>tuple2function_t</code> - creates a function signature type (<code>R(T1,T2,...)</code>) according to a list of tuple arguments (<code>tuple<T1,T2,...></code>).
* <code>function2tuple_t</code> - the inverse of the above.
<a name="cxxo-sup-type_traits"></a>
<h3>Supplementals for <type_traits></h3>
<verbatim>
#include <cxxomfort/library/type_traits.hpp>
</verbatim>
Type_traits to recognize types, that are either implemented here or pulled from other cxxomfort facilities into the header:
<verbatim>
is_std_array --> std::array<T,N>
is_std_byte --> std::byte
is_std_function --> std::function<Signature>
is_iterator --> Any type that specializes std::iterator_traits
is_pair --> std::pair<A,B>
is_tuple --> std::tuple<...>
is_sequence --> Any type that provides a begin() and end()
is_enumeration_like --> enum { ... } or any type that implements typesafe_enum<...>
</verbatim>
<a name="cxxo-sup-utility"></a>
<h3>Supplementals for <utility></h3>
<verbatim>
#include <cxxomfort/library/utility.hpp>
</verbatim>
[http://ryan.gulix.cl/cxxomfort-docs/html/cxxo-sup-utility.html|Listing of the functions and interfaces included in this supplement].
<h2>Other Features</h2>
The following traits are available in <code>cxxomfort/utilities.hpp</code> as assistance when writing generic / quasi-generic code.
<h4><code>is_any_of</code></h4>
Given a type <em>T</em> and a list of types <em>A1, A2, …, A9</em>, the trait <code>is_any_of<T, A1, A2, …, A9></code> inherits from <code>std::true_type</code> if:
* T is an exact <u>cv-qualified match</u> for any of the types A1, A2, …, A9.
In both C++03 and C++11, this trait can take up to 10 candidate types.
<h4><code>result_of_function</code></h4>
Given a type <em>T</em>, the trait <code>result_of_function<T></code> defines the member type <code>::type</code>, as a type to-be-determined below, if:
* T is a type signature of a function type eg.: <code>T = R(A1,A2, …)</code>. In this case, <code>type: R</code>.
* T is a pointer type to the above eg.: <code>T = R(*)(A1,A2,…)</code>. In this case, <code>type</code> is defined as in the above.
* (<b>Not implemented yet</b>) T is <code>std::random_device</code>. In this case, <code>type: unsigned int</code>.
In C++03 mode, this trait can recognize function types up to 10 arguments.
<h4><code>integral_of_size</code></h4>
Given a compile-time integer <em>N</em>, with <code>N≥0</code>, this trait defines the member type <code>::type</code>, as a type to-be-determined-below, if:
* There exists a native signed integral type <em>I</em> such that <code>sizeof(I)==N</code>. In this case, <code>type: I</code>.
If there is no integral type for the given value of <em>N</em>, instantiation of this template results in an error.
<h3>Utility Functions</h3>
<h4><code>null_device</code></h4>
This trait defines the static member variable <code>const char* value</code> as the literal string corresponding to the "null device" recognized by the OS in the current compiler.
* Under POSIX, this is <code>"/dev/null"</code>
* Under Microsoft Windows, this is <code>"NUL"</code>.
* Under other systems this is left a null-string.
----
<b>C++ [Features]</b> -- <b>[Cxxomfort|Back to the beginning]</b>
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