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C++11 constexpr variables support added

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This commit is contained in:
William S Fulton 2014-03-10 07:07:39 +00:00
commit e186dc13b7
3 changed files with 36 additions and 15 deletions
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21
Doc/Manual/CPlusPlus11.html
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@ -107,7 +107,7 @@ For example, ignore the move constructor:
</pre></div> </pre></div>
<p> <p>
The plan is to ignore them by default in a future version of SWIG. Note that both normal assignment operators as well as move assignment operators are ignored by default in most target languages with the following warning: The plan is to ignore move constructors by default in a future version of SWIG. Note that both normal assignment operators as well as move assignment operators are ignored by default in most target languages with the following warning:
</p> </p>
<div class="shell"> <div class="shell">
@ -120,20 +120,19 @@ example.i:18: Warning 503: Can't wrap 'operator =' unless renamed to a valid ide
<H3><a name="CPlusPlus11_generalized_constant_expressions"></a>7.2.2 Generalized constant expressions</H3> <H3><a name="CPlusPlus11_generalized_constant_expressions"></a>7.2.2 Generalized constant expressions</H3>
<p>SWIG correctly parses the keyword <tt>constexpr</tt>, but ignores its functionality. Constant functions cannot be used as constants.</p> <p>SWIG parses and identifies the keyword <tt>constexpr</tt>, but cannot fully utilise it.
These C++ compile time constants are usable as runtime constants from the target languages.
Below shows example usage for assigning a C++ compile time constant from a compile time constant function:
</p>
<div class="code"><pre> <div class="code"><pre>
constexpr int myConstFunc() { return 10; } constexpr int XXX() { return 10; }
const int a = myConstFunc(); // results in error constexpr int YYY = XXX() + 100;
</pre></div> </pre></div>
<p>Users needs to use values or predefined constants when defining the new constant value:</p> <p>
When either of these is used from a target language, a runtime call is made to obtain the underlying constant.
<div class="code"><pre> </p>
#define MY_CONST 10
constexpr int myConstFunc() { return MY_CONST; }
const int a = MY_CONST; // ok
</pre></div>
<H3><a name="CPlusPlus11_extern_template"></a>7.2.3 Extern template</H3> <H3><a name="CPlusPlus11_extern_template"></a>7.2.3 Extern template</H3>

28
Examples/test-suite/cpp11_constexpr.i
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@ -4,9 +4,31 @@
%module cpp11_constexpr %module cpp11_constexpr
%inline %{ %inline %{
class TestClass { constexpr int AAA = 10;
public: constexpr const int BBB = 20;
constexpr int func() { return 10; } constexpr int CCC() { return 30; }
constexpr const int DDD() { return 40; }
constexpr int XXX() { return 10; }
constexpr int YYY = XXX() + 100;
struct ConstExpressions {
static constexpr const int JJJ = 100;
static constexpr int KKK = 200;
static const int LLL = 300;
constexpr int MMM() { return 400; }
constexpr const int NNN() { return 500; }
}; };
%} %}
%{
int Array10[AAA];
int Array20[BBB];
int Array30[CCC()];
int Array40[DDD()];
int Array100[ConstExpressions::JJJ];
int Array200[ConstExpressions::KKK];
int Array300[ConstExpressions::LLL];
//int Array400[ConstExpressions::MMM()];
//int Array500[ConstExpressions::NNN()];
%}

2
Source/CParse/parser.y
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@ -412,7 +412,7 @@ static void add_symbols(Node *n) {
} else { } else {
ty = type; ty = type;
} }
if (!SwigType_ismutable(ty)) { if (!SwigType_ismutable(ty) || (storage && Strstr(storage, "constexpr"))) {
SetFlag(n,"hasconsttype"); SetFlag(n,"hasconsttype");
SetFlag(n,"feature:immutable"); SetFlag(n,"feature:immutable");
} }