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// file : build/variable -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
// license : MIT; see accompanying LICENSE file
#ifndef BUILD_VARIABLE
#define BUILD_VARIABLE
#include <string>
#include <memory> // unique_ptr
#include <utility> // move()
#include <cassert>
#include <typeindex>
#include <unordered_set>
#include <build/path>
#include <build/name>
#include <build/prefix-map>
namespace build
{
class scope;
struct value;
struct value_type
{
std::type_index id;
value* (*const factory) ();
};
// variable
//
// The two variables are considered the same if they have the same name.
//
struct variable
{
explicit
variable (std::string n): name (std::move (n)), type (nullptr) {}
std::string name;
const value_type* type; // If NULL, then this variable has no fixed type.
};
inline bool
operator== (const variable& x, const variable& y) {return x.name == y.name;}
typedef std::reference_wrapper<const variable> variable_cref;
// value
//
struct value
{
typedef build::scope scope_type;
virtual
~value () = default;
value (scope_type& s): scope (s) {}
scope_type& scope; // Scope to which this value belongs.
};
typedef std::unique_ptr<value> value_ptr;
struct list_value: value
{
list_value (scope_type& s, names d): value (s), data (std::move (d)) {}
list_value (scope_type& s, std::string d)
: value (s)
{
data.emplace_back (std::move (d));
}
// Note: stored in name as a directory.
//
list_value (scope_type& s, path d)
: value (s)
{
data.emplace_back (std::move (d));
}
names data;
};
typedef std::unique_ptr<list_value> list_value_ptr;
// value_proxy
//
struct value_proxy
{
explicit operator bool () const {return p != nullptr && *p != nullptr;}
explicit operator value_ptr& () const {return *p;}
// Get interface. See available specializations below.
//
template <typename T>
T
as () const = delete;
// Set interface.
//
const value_proxy&
operator= (value_ptr v) const
{
assert (v == nullptr || &v->scope == s);
*p = std::move (v);
return *this;
}
const value_proxy&
operator= (std::string v) const
{
// In most cases this is used to initialize a new variable, so
// don't bother trying to optimize for the case where p is not
// NULL.
//
p->reset (new list_value (*s, std::move (v)));
return *this;
}
// Note: stored in name as a directory.
//
const value_proxy&
operator= (path v) const
{
p->reset (new list_value (*s, std::move (v)));
return *this;
}
// Implementation details.
//
explicit
value_proxy (value_ptr* p, scope* s): p (p), s (s) {}
protected:
value_ptr* p;
scope* s;
};
template <>
list_value& value_proxy::
as<list_value&> () const;
template <>
const std::string& value_proxy::
as<const std::string&> () const;
// Note: get the name's directory.
//
template <>
const path& value_proxy::
as<const path&> () const;
}
namespace std
{
template <>
struct hash<build::variable>: hash<string>
{
size_t
operator() (const build::variable& v) const noexcept
{
return hash<string>::operator() (v.name);
}
};
}
namespace build
{
// variable_pool
//
struct variable_set: std::unordered_set<variable>
{
// @@ Need to check/set type?
//
const variable&
find (std::string name) {return *emplace (std::move (name)).first;}
};
extern variable_set variable_pool;
// variable_map
//
template <>
struct compare_prefix<variable_cref>: compare_prefix<std::string>
{
typedef compare_prefix<std::string> base;
explicit
compare_prefix (char d): base (d) {}
bool
operator() (const variable& x, const variable& y) const
{
return base::operator() (x.name, y.name);
}
bool
prefix (const variable& p, const variable& k) const
{
return base::prefix (p.name, k.name);
}
};
struct variable_map: prefix_map<variable_cref, value_ptr, '.'>
{
typedef prefix_map<variable_cref, value_ptr, '.'> base;
value_proxy
operator[] (const std::string& v)
{
return operator[] (variable_pool.find (v));
}
value_proxy
operator[] (const variable& v)
{
return value_proxy (&base::operator[] (v), &scope_);
}
explicit
variable_map (scope& s): scope_ (s) {}
private:
scope& scope_; // Scope to which this map belongs (and all its value).
};
}
#endif // BUILD_VARIABLE
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