ada形式文法.zip

/* * The detection that an identifer is actually an Ada reserved * word is done via a hash function. See SIGAda Letters V4 N1 * pages 40-44 for more information regarding the hash technique. */ #include <ctype.h> #include "y.tab.h" #define ERROR_TOKEN 0 typedef struct reserved_word_entry { char *text_value; int token_value; } reserved_word_entry; static reserved_word_entry reserved_word_table[ 71 ] = { { "else" , ELSE_ }, { "exit" , EXIT_ }, { "end" , END_ }, { "at" , AT_ }, { "then" , THEN_ }, { "range" , RANGE_ }, { "abs" , ABS_ }, { "do" , DO_ }, { "exception", EXCEPTION_ }, { "delay" , DELAY_ }, { "use" , USE_ }, { "xor" , XOR_ }, { "select" , SELECT_ }, { "" , ERROR_TOKEN }, { "declare" , DECLARE_ }, { "type" , TYPE_ }, { "array" , ARRAY_ }, { "limited" , LIMITED_ }, { "subtype" , SUBTYPE_ }, { "elsif" , ELSIF_ }, { "case" , CASE_ }, { "generic" , GENERIC_ }, { "and" , AND_ }, { "not" , NOT_ }, { "renames" , RENAMES_ }, { "package" , PACKAGE_ }, { "null" , NULL_ }, { "separate" , SEPARATE_ }, { "terminate", TERMINATE_ }, { "raise" , RAISE_ }, { "entry" , ENTRY_ }, { "reverse" , REVERSE_ }, { "task" , TASK_ }, { "" , ERROR_TOKEN }, { "all" , ALL_ }, { "constant" , CONSTANT_ }, { "delta" , DELTA_ }, { "accept" , ACCEPT_ }, { "digits" , DIGITS_ }, { "return" , RETURN_ }, { "abort" , ABORT_ }, { "record" , RECORD_ }, { "in" , IN_ }, { "access" , ACCESS_ }, { "or" , OR_ }, { "function" , FUNCTION_ }, { "goto" , GOTO_ }, { "others" , OTHERS_ }, { "rem" , REM_ }, { "procedure", PROCEDURE_ }, { "out" , OUT_ }, { "private" , PRIVATE_ }, { "is" , IS_ }, { "mod" , MOD_ }, { "of" , OF_ }, { "" , ERROR_TOKEN }, { "pragma" , PRAGMA_ }, { "for" , FOR_ }, { "new" , NEW_ }, { "when" , WHEN_ }, { "with" , WITH_ }, { "begin" , BEGIN_ }, { "" , ERROR_TOKEN }, { "while" , WHILE_ }, { "" , ERROR_TOKEN }, { "" , ERROR_TOKEN }, { "" , ERROR_TOKEN }, { "loop" , LOOP_ }, { "" , ERROR_TOKEN }, { "if" , IF_ }, { "body" , BODY_ } }; static int magic_table[ 26 ] = { 0, 49, 0, -7, -20, 18, -2, -38, 33, 0, -9, 9, 29, -9, 6, 26, 0, 8, 1, 1, -9, 0, 56, -28, 11, 0 }; int reserved_word( word ) char *word; { int index; int hash_value; int word_length = strlen( word ); char canonical_word[ 1024 ]; /* * Check some simple things first: * - it has the correct length, must be >= 2 and <= 9 * - it doesn't have any digits in important (for the hash) places */ if ( ( word_length < 2 ) || ( word_length > 9 ) || ( isdigit( word[ 0 ] ) ) || ( isdigit( word[ word_length - 1 ] ) ) || ( isdigit( word[ word_length - 2 ] ) ) ) { return identifier; } /* convert the identifier to all lower case characters */ for ( index = 0; *word; word++, index++ ) { canonical_word[ index ] = isupper( *word ) ? tolower( *word ) : *word; } /* compute the magic hash value */ hash_value = magic_table[ canonical_word[ 0 ] - 'a' ] + magic_table[ canonical_word[ word_length - 1 ] - 'a' ] + ( 2 * ( canonical_word[ word_length - 2 ] - 'a' ) ) + word_length; if ( ( hash_value >= 0 ) && ( hash_value <= 70 ) && ( strncmp( canonical_word, reserved_word_table[ hash_value ].text_value, word_length ) == 0 ) ) { return reserved_word_table[ hash_value ].token_value; } else { return identifier; } }