Ichthyostega
c7d157e295
...built while investigating type deduction problems on PtrDerefIter ...also allow PtrDerefIter to work with std::unique_ptr
122 lines
4.9 KiB
C++
122 lines
4.9 KiB
C++
/* try.cpp - for trying out some language features....
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* scons will create the binary bin/try
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*
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*/
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// 8/07 - how to control NOBUG??
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// execute with NOBUG_LOG='ttt:TRACE' bin/try
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// 1/08 - working out a static initialisation problem for Visitor (Tag creation)
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// 1/08 - check 64bit longs
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// 4/08 - comparison operators on shared_ptr<Asset>
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// 4/08 - conversions on the value_type used for boost::any
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// 5/08 - how to guard a downcasting access, so it is compiled in only if the involved types are convertible
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// 7/08 - combining partial specialisation and subclasses
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// 10/8 - abusing the STL containers to hold noncopyable values
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// 6/09 - investigating how to build a mixin template providing an operator bool()
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// 12/9 - tracking down a strange "warning: type qualifiers ignored on function return type"
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// 1/10 - can we determine at compile time the presence of a certain function (for duck-typing)?
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// 4/10 - pretty printing STL containers with python enabled GDB?
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// 1/11 - exploring numeric limits
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// 1/11 - integer floor and wrap operation(s)
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// 1/11 - how to fetch the path of the own executable -- at least under Linux?
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// 10/11 - simple demo using a pointer and a struct
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// 11/11 - using the boost random number generator(s)
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// 12/11 - how to detect if string conversion is possible?
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// 1/12 - is partial application of member functions possible?
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// 5/14 - c++11 transition: detect empty function object
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// 7/14 - c++11 transition: std hash function vs. boost hash
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// 9/14 - variadic templates and perfect forwarding
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// 11/14 - pointer to member functions and name mangling
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// 8/15 - Segfault when loading into GDB (on Debian/Jessie 64bit
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// 8/15 - generalising the Variant::Visitor
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// 1/16 - generic to-string conversion for ostream
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// 1/16 - build tuple from runtime-typed variant container
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// 3/17 - generic function signature traits, including support for Lambdas
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// 9/17 - manipulate variadic templates to treat varargs in several chunks
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// 11/17 - metaprogramming to detect the presence of extension points
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// 11/17 - detect generic lambda
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// 12/17 - investigate SFINAE failure. Reason was indirect use while in template instantiation
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// 03/18 - Dependency Injection / Singleton initialisation / double checked locking
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// 04/18 - investigate construction of static template members
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// 08/18 - Segfault when compiling some regular expressions for EventLog search
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// 10/18 - investigate insidious reinterpret cast
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// 12/18 - investigate the trinomial random number algorithm from the C standard lib
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// 04/19 - forwarding tuple element(s) to function invocation
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// 06/19 - use a statefull counting filter in a treeExplorer pipeline
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// 03/20 - investigate type deduction bug with PtrDerefIter
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/** @file try.cpp
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* Compiling a seemingly valid iterator pipeline failed, due to type deduction problems.
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* As expected, they originate within PtrDerefIter, which I abused here to dereference
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* an unique_ptr -- which might seem strange, yet is true to the spirit of generic programming.
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* Since I consider this a valid usage, the fix is to add a further specialisation to my
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* hand-written RemovePtr trait template in iter-adapter-ptr-deref.hpp (which also justifies
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* in hindsight to use a hand-written trait right within this header, instead of some library).
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*/
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typedef unsigned int uint;
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namespace std {
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template <typename _Tp, typename _Dp>
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class unique_ptr;
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}
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#include "lib/format-cout.hpp"
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#include "lib/test/test-helper.hpp"
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#include "lib/util.hpp"
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#include "lib/iter-adapter-ptr-deref.hpp"
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#include "lib/iter-adapter-stl.hpp"
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#include "lib/itertools.hpp"
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#include "lib/util-coll.hpp"
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#include <utility>
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#include <string>
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#include <vector>
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#include <memory>
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#include <type_traits>
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using std::string;
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using std::make_unique;
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using util::max;
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#define SHOW_TYPE(_TY_) \
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cout << "typeof( " << STRINGIFY(_TY_) << " )= " << lib::meta::typeStr<_TY_>() <<endl;
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#define SHOW_EXPR(_XX_) \
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cout << "Probe " << STRINGIFY(_XX_) << " ? = " << _XX_ <<endl;
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using PStr = std::unique_ptr<string>;
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using Strs = std::vector<PStr>;
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constexpr auto elems = [](auto& coll) { return lib::ptrDeref (lib::iter_stl::eachElm (coll)); };
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int
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main (int, char**)
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{
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Strs ss;
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ss.emplace_back(new string{"li"});
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ss.emplace_back(new string{"la"});
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ss.emplace_back(new string{"lutsch"});
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SHOW_EXPR (ss);
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SHOW_EXPR (elems(ss));
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using ITS = decltype(elems(ss));
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SHOW_TYPE (ITS);
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// using ITSR = typename ITS::reference;
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// lib::test::TypeDebugger<ITSR> buggy;
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auto dings = elems(ss);
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int maxVSize = max (lib::transformIterator(dings,
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[](string const& ding)
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{
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return ding.length();
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}));
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SHOW_EXPR (maxVSize);
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cout << "\n.gulp.\n";
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return 0;
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}
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