3.8.3 ¥¹¥¿¡¼¥È¾õÂ֤˴ؤ¹¤ëÃí

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• Æüìʸ»ú

  £±¤Ä¤Î¥ë¡¼¥ë¤Ë¤ª¤¤¤Æ¤Ï¡¢ ñ°ì¤Î¥¹¥¿¡¼¥È¾õÂÖ¡¢ ¤Þ¤¿¤Ï¡¢ ¥«¥ó¥Þ¤Ç¶èÀÚ¤é¤ì¤¿¥¹¥¿¡¼¥È¾õÂ֤Υꥹ¥È¤Î¤ß¤ò»ÈÍѤ¹¤ë¤³¤È¤¬¤Ç¤­¤Þ¤¹¡£ ¤Þ¤¿¡¢ ¤³¤¦¤·¤¿¥¹¥¿¡¼¥È¾õÂ֤λØÄê¤Ï¥ë¡¼¥ë¤ÎÀèƬ¤Ë¤Ê¤±¤ì¤Ð¤Ê¤ê¤Þ¤»¤ó¡£ ¼¡¤Ë¼¨¤¹¤â¤Î¤ÏÀµÅö¤Ç¤¹¡£

  %x state1
  %s state2
  %%
  <state1> "something"
  <state2> "another thing"
  <state, state2> "something else"
  

  ¤·¤«¤·¡¢ ¼¡¤Ë¼¨¤¹¤â¤Î¤ÏÉÔÅö¤Ç¤¹¡£

  %x state1
  %s state2
  %%
  wrong<state1>
  <state1><state2>"wrong"
  <state2>"wrong"<state1>
  

• ÇÓ¾Ū¥¹¥¿¡¼¥È¾õÂÖ

  ÇÓ¾Ū¥¹¥¿¡¼¥È¾õÂ֤ϡ¢ ¾¤Î¤¹¤Ù¤Æ¤Î¾õÂÖ¤ò¡Ö̵¸ú¡×¤Ë¤¹¤ë¤Î¤Ç¡¢ ¶¯ÎϤǤ¹¡£ ¤³¤ì¤Ï¡¢ ¥¹¥­¥ã¥Ê¤ÎÆâÉô¤Ë¤ª¤¤¤Æ¤â¤¦£±¤Ä¤Î¥¹¥­¥ã¥Ê¤ò¸ú²ÌŪ¤ËÄêµÁ¤¹¤ë¤³¤È¤¬¤Ç¤­¤ë¤³¤È¤ò°ÕÌ£¤·¤Æ¤¤¤Þ¤¹¡£ ¤³¤ì¤Ë¤è¤êÎ㤨¤Ð¡¢ ¥¹¥¿¡¼¥È¾õÂÖ¼¡Âè¤Ç¡¢ C¤ÈPascal¤ÎξÊý¤ò¥¹¥­¥ã¥ó¤¹¤ë¥¹¥­¥ã¥Ê¤òÄêµÁ¤¹¤ë¤³¤È¤¬¡¢ ÍýÏÀŪ¤Ë¤Ï²Äǽ¤Ë¤Ê¤ê¤Þ¤¹¡£ °Ê²¼¤Î¤è¤¦¤Ê¥³¡¼¥É¤¬»ý¤Ä¸ú²Ì¤òÁÛÁü¤·¤Æ¤ß¤Æ¤¯¤À¤µ¤¤¡£

  %x PASCAL
  %x C
  %%
  <PASCAL>begin     return(OPEN_BLOCK);
  <PASCAL>end       return(CLOSE_BLOCK);
  <C>{              return(OPEN_BLOCK);
  <C>}              return(CLOSE_BLOCK);
  

• ¥¹¥¿¡¼¥È¾õÂÖ¤Î̾Á°

  Á°½Ò¤Î¤È¤ª¤ê¡¢ ¥¹¥¿¡¼¥È¾õÂ֤Ϥ½¤ì¼«¿È¤Î̾Á°¶õ´Ö¤ò»ý¤Ã¤Æ¤¤¤Þ¤»¤ó¡£ ¤½¤ÎÍýͳ¤Ï¡¢ ¥¹¥¿¡¼¥È¾õÂÖ¤¬#define¤È¤Û¤È¤ó¤ÉƱ¤¸ÊýË¡¤ÇÀ°¿ôÃͤȤ·¤ÆÄêµÁ¤µ¤ì¤Æ¤¤¤ë¤«¤é¤Ç¤¹¡£ ¤³¤Î¤³¤È¤Ï¡¢ À°¿ôÃͤÈƱÍÍ¡¢ ¥¹¥¿¡¼¥È¾õÂ֤Ρ֥¹¥¿¥Ã¥¯¡×¤Î¤è¤¦¤Ê¤â¤Î¤òºîÀ®¤¹¤ë¤³¤È¤¬²Äǽ¤Ç¤¢¤ë¤³¤È¤ò°ÕÌ£¤·¤Æ¤¤¤Þ¤¹¡£ Î㤨¤Ð¡¢

  %{
      int last_state[MAX_STATES]
      int state_count = 0;
  %}
  %x FOO BAR baz
  %%
  FOO        {
                last_state[state_count] = FOO;
                state_count++; 
                BEGIN(baz);
             }
  

  BAR        {
                last_state[state_count] = BAR;
                state_count++; 
                BEGIN(baz);
             }
  

  <baz>rule 1
       …  
  <baz>rule n
  <baz>END   {
                statecount--;
                BEGIN(last_state[statecount]);
             } 
  

  ¤ÏFOO¤ÈBAR¤ÎξÊý¤Ë¤è¤Ã¤Æbaz¾õÂÖ¤ò³èÀ­²½¤µ¤»¡¢ <baz>END¤È¤¤¤¦¥ë¡¼¥ë¤Ë¤è¤Ã¤Æ£±¤ÄÁ°¤Î¾õÂÖ¤ËÌᤷ¤Þ¤¹¡£ ¤³¤¦¤·¤¿¡Ö¾õÂÖ¥¹¥¿¥Ã¥¯¡×¤Ï¾­Íè¡¢ Flex¤ÎÆÃħŪ¤Êµ¡Ç½¤Ë¤Ê¤ë¤«¤â¤·¤ì¤Þ¤»¤ó¡£⁴