parse_location.h

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#ifndef PARSE_LOCATION_INCLUDED
#define PARSE_LOCATION_INCLUDED

#include <cstdlib>  // size_t

/**
  Helper class for the YYLTYPE
*/
struct Symbol_location {
  const char *start;  // token start
  const char *end;    // the 1st byte after the token

  bool is_empty() const { return length() == 0; }
  size_t length() const { return static_cast<size_t>(end - start); }
};

/**
  Bison "location" class
*/
struct YYLTYPE {
  Symbol_location cpp;  // token location in the preprocessed buffer
  Symbol_location raw;  // token location in the raw buffer

  bool is_empty() const { return cpp.is_empty(); }
};

/*
  Note: YYLTYPE doesn't overload a default constructor (as well an underlying
  Symbol_location).
  OTOH if we need a zero-initialized POS, YYLTYPE or Symbol_location object,
  we can simply call POS(), YYLTYPE() or Symbol_location(): C++ does
  value-initialization in that case.
*/
typedef YYLTYPE POS;

#define YYLTYPE_IS_DECLARED 1  // signal Bison that we have our own YYLTYPE

/**
  Bison calls this macro:
  1. each time a rule is matched and
  2. to compute a syntax error location.

  @param [out] Current location of the whole matched rule
  @param Rhs           locations of all right hand side elements in the rule
  @param N             number of right hand side elements in the rule
*/
#define YYLLOC_DEFAULT(Current, Rhs, N)                                   \
  do                                                                      \
    if (N) {                                                              \
      (Current).cpp.start = YYRHSLOC(Rhs, 1).cpp.start;                   \
      (Current).cpp.end = YYRHSLOC(Rhs, N).cpp.end;                       \
      (Current).raw.start = YYRHSLOC(Rhs, 1).raw.start;                   \
      (Current).raw.end = YYRHSLOC(Rhs, N).raw.end;                       \
    } else {                                                              \
      (Current).cpp.start = (Current).cpp.end = YYRHSLOC(Rhs, 0).cpp.end; \
      (Current).raw.start = (Current).raw.end = YYRHSLOC(Rhs, 0).raw.end; \
    }                                                                     \
  while (0)

#endif /* PARSE_LOCATION_INCLUDED */