private String yysyntax_error()

in msys2/usr/share/bison/skeletons/lalr1.java [905:975]

• 38 lines of code
• 16 McCabe index (conditional complexity)

  private String yysyntax_error (int yystate, int tok)
  {]b4_error_verbose_if([[
    if (yyErrorVerbose)
      {
        /* There are many possibilities here to consider:
           - If this state is a consistent state with a default action,
             then the only way this function was invoked is if the
             default action is an error action.  In that case, don't
             check for expected tokens because there are none.
           - The only way there can be no lookahead present (in tok) is
             if this state is a consistent state with a default action.
             Thus, detecting the absence of a lookahead is sufficient to
             determine that there is no unexpected or expected token to
             report.  In that case, just report a simple "syntax error".
           - Don't assume there isn't a lookahead just because this
             state is a consistent state with a default action.  There
             might have been a previous inconsistent state, consistent
             state with a non-default action, or user semantic action
             that manipulated yychar.  (However, yychar is currently out
             of scope during semantic actions.)
           - Of course, the expected token list depends on states to
             have correct lookahead information, and it depends on the
             parser not to perform extra reductions after fetching a
             lookahead from the scanner and before detecting a syntax
             error.  Thus, state merging (from LALR or IELR) and default
             reductions corrupt the expected token list.  However, the
             list is correct for canonical LR with one exception: it
             will still contain any token that will not be accepted due
             to an error action in a later state.
        */
        if (tok != yyempty_)
          {
            /* FIXME: This method of building the message is not compatible
               with internationalization.  */
            StringBuffer res =
              new StringBuffer ("syntax error, unexpected ");
            res.append (yytnamerr_ (yytname_[tok]));
            int yyn = yypact_[yystate];
            if (!yy_pact_value_is_default_ (yyn))
              {
                /* Start YYX at -YYN if negative to avoid negative
                   indexes in YYCHECK.  In other words, skip the first
                   -YYN actions for this state because they are default
                   actions.  */
                int yyxbegin = yyn < 0 ? -yyn : 0;
                /* Stay within bounds of both yycheck and yytname.  */
                int yychecklim = yylast_ - yyn + 1;
                int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
                int count = 0;
                for (int x = yyxbegin; x < yyxend; ++x)
                  if (yycheck_[x + yyn] == x && x != yyterror_
                      && !yy_table_value_is_error_ (yytable_[x + yyn]))
                    ++count;
                if (count < 5)
                  {
                    count = 0;
                    for (int x = yyxbegin; x < yyxend; ++x)
                      if (yycheck_[x + yyn] == x && x != yyterror_
                          && !yy_table_value_is_error_ (yytable_[x + yyn]))
                        {
                          res.append (count++ == 0 ? ", expecting " : " or ");
                          res.append (yytnamerr_ (yytname_[x]));
                        }
                  }
              }
            return res.toString ();
          }
      }
]])[
    return "syntax error";
  }