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// file : build2/cc/lexer.hxx -*- C++ -*-
// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef BUILD2_CC_LEXER_HXX
#define BUILD2_CC_LEXER_HXX
#include <libbutl/char-scanner.hxx>
#include <build2/types.hxx>
#include <build2/utility.hxx>
#include <build2/diagnostics.hxx>
namespace build2
{
namespace cc
{
// Preprocessor-level tokenization of C/C++ source. In other words, the
// sequence of tokens returned is similar to what a real C/C++ compiler
// would see from its preprocessor.
//
// The input is a (partially-)preprocessed translation unit that may still
// contain comments, line continuations, and preprocessor directives such
// as #line, #pragma, etc. Currently all preprocessor directives are
// discarded and no values are saved for literals.
//
enum class token_type
{
// NOTE: remember to update operator<<() if changing anything here!
//
eos,
dot, // .
semi, // ;
lcbrace, // {
rcbrace, // }
punctuation, // Other punctuation.
identifier,
number, // Number literal.
character, // Char literal.
string, // String literal.
other // Other token.
};
struct token
{
token_type type;
string value;
uint64_t line;
uint64_t column;
public:
token ()
: token (token_type::eos, 0, 0) {}
token (token_type t, uint64_t l, uint64_t c)
: token (t, string (), l, c) {}
token (token_type t, string v, uint64_t l, uint64_t c)
: type (t), value (move (v)), line (l), column (c) {}
};
// Output the token value in a format suitable for diagnostics.
//
ostream&
operator<< (ostream&, const token&);
class lexer: protected butl::char_scanner
{
public:
lexer (istream& is, const path& name)
: char_scanner (is, false), name_ (name), fail ("error", &name_) {}
const path&
name () const {return name_;}
// Note that it is ok to call next() again after getting eos.
//
token
next ()
{
token t;
next (t, skip_spaces (), true);
return t;
}
// As above but reuse the token to avoid a (potential) memory
// allocation. Typical usage:
//
// for (token t; l.next (t) != token_type::eos; )
// ...
//
token_type
next (token& t)
{
next (t, skip_spaces (), true);
return t.type;
}
private:
void
next (token&, xchar, bool);
void
number_literal (token&, xchar);
void
char_literal (token&, xchar);
void
string_literal (token&, xchar);
void
raw_string_literal (token&, xchar);
void
literal_suffix (xchar);
xchar
skip_spaces (bool newline = true);
// The char_scanner adaptation for newline escape sequence processing.
// Enabled by default and is only disabled in the raw string literals.
//
private:
using base = char_scanner;
xchar
get (bool escape = true);
void
get (const xchar& peeked) {base::get (peeked);}
xchar
peek (bool escape = true);
private:
const path name_;
const fail_mark fail;
};
// Diagnostics plumbing. We assume that any diag stream for which we can
// use token as location has its aux data pointing to pointer to path.
//
inline location
get_location (const token& t, const path& p)
{
return location (&p, t.line, t.column);
}
inline location
get_location (const token& t, const void* data)
{
assert (data != nullptr); // E.g., must be &parser::path_.
const path* p (*static_cast<const path* const*> (data));
return get_location (t, *p);
}
}
}
#endif // BUILD2_CC_LEXER_HXX
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