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// file : build/config/utility.txx -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#include <utility> // move()
#include <build/scope>
#include <build/variable>
namespace build
{
namespace config
{
template <typename T>
std::pair<const T&, bool>
required (scope& root, const char* name, const T& def_value)
{
T r;
const variable& var (variable_pool.find (name));
if (auto v = root[var])
{
const T& s (v.as<const T&> ());
if (!v.belongs (*global_scope)) // A value from (some) config.build.
return std::pair<const T&, bool> (s, false);
r = s;
}
else
r = def_value;
auto v (root.assign (var));
v = std::move (r);
return std::pair<const T&, bool> (v.as<const T&> (), true);
}
template <typename T>
const T*
optional (scope& root, const char* name)
{
const T* r (nullptr);
const variable& var (variable_pool.find (name));
auto v (root[var]);
if (v.defined ())
{
if (v.belongs (*global_scope))
root.assign (var) = v;
r = v.null () ? nullptr : &v.as<const T&> ();
}
else
root.assign (var) = nullptr;
return r;
}
}
}
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