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// file : build/lexer -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
// license : MIT; see accompanying LICENSE file
#ifndef BUILD_LEXER
#define BUILD_LEXER
#include <string>
#include <iosfwd>
#include <cstdint> // uint64_t
#include <exception>
#include <build/token>
#include <build/diagnostics>
namespace build
{
class lexer
{
public:
lexer (std::istream& is, const std::string& name): is_ (is), fail (name) {}
token
next ();
// Character interface.
//
private:
class xchar
{
public:
typedef std::char_traits<char> traits_type;
typedef traits_type::int_type int_type;
typedef traits_type::char_type char_type;
xchar (int_type v, std::uint64_t l, std::uint64_t c)
: v_ (v), l_ (l), c_ (c) {}
operator char_type () const {return static_cast<char_type> (v_);}
int_type
value () const {return v_;}
std::uint64_t line () const {return l_;}
std::uint64_t column () const {return c_;}
private:
int_type v_;
std::uint64_t l_;
std::uint64_t c_;
};
xchar
peek ();
xchar
get ();
void
unget (const xchar&);
// Tests.
//
bool
is_eos (const xchar& c) const
{
return c.value () == xchar::traits_type::eof ();
}
// Scanner.
//
private:
xchar
escape ();
void
skip_spaces ();
token
name (xchar);
// Diagnostics.
//
private:
struct fail_mark_base: build::fail_mark_base<failed>
{
fail_mark_base (const std::string& n): name_ (n) {}
location_prologue
operator() (const xchar&) const;
std::string name_;
};
typedef diag_mark<fail_mark_base> fail_mark;
private:
std::istream& is_;
fail_mark fail;
std::uint64_t l_ {1};
std::uint64_t c_ {1};
bool unget_ {false};
xchar buf_ {0, 0, 0};
bool eos_ {false};
// Context-dependent lexing mode. In the value mode we don't treat
// certain characters (e.g., +, =) as special so that we can use
// them in the variable values, e.g., 'foo = g++'.
//
enum class mode {normal, value};
mode mode_ {mode::normal};
};
}
#endif // BUILD_LEXER
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