递归下降法的语法分析器-3-编译原理
递归下降法的语法分析器
一、实验目的
掌握语法分析器的构造原理，掌握递归下降法的编程方法。
二、实验内容
用递归下降法编写一个语法分析程序，使之与词法分析器结合，能够根据语言的上下文无关文法，识别输入的单词序列是否文法的句子。（注意，需要改写文法，消除左递归等）
program → block
block → { stmts }
stmts → stmt stmts | e
stmt → id= expr ;
| if ( bool ) stmt
| if ( bool) stmt else stmt
| while (bool) stmt
| do stmt while (bool ) ;
| break ;
| block
bool → expr < expr
| expr <= expr
| expr > expr
| expr >= expr
| expr
expr → expr + term
| expr - term
| term
term → term * factor
| term / factor
| factor
factor → ( expr ) | id| num
三、实验要求
１．个人完成，提交实验报告。
２．实验报告中给出采用测试源代码片断，及其对应的最左推导过程（形式可以自行考虑）。
程序片断
{
i = 2;
while (i <=100)
{
sum = sum + i;
i = i + 2;
}
}
对应的推导过程为：
实验文件： main.cpp ，parse.cpp， yytex.cpp ，yytex.h ，a.txt
四、实验说明
- 1. 词法分析器的说明
本实验使用“实验2 用FLEX实现词法分析器”的生成的代码。其中每次调用一次yylex()函数就可以获取一个词法单元。
- 2. 公共左因子的处理
本实验使用的是公共左因子，需要考虑改造文法。其中：
如果lookahead是词法单元else时，使用产生式else_part → else stmt；否则使用产生式else_part → e
- 3. 预测分析器
假设是将上述文法改造为LL(1)文法，同时采用带预测的递归下降进行语法分析。预测分析器的部分代码是：
1 stmt()函数
View Code
void stmt() { switch(Lookahead) { case ID_TKN: printf("\nstmt->ID=expr;\n"); match(ID_TKN);match(RELOP_TKN);Expr();match(RELOP_TKN);break; case IF_TKN: printf("\nstmt->IF(bool) stmt else_part \n"); match(IF_TKN);match(LEFT_BRACKET);bool_();match(RIGHT_BRACKET);stmt();match(ELSE_TKN);else_part();break; case WHILE_TKN: printf("\nstmt->WHILE (bool) stmt \n"); match(WHILE_TKN);match(LEFT_BRACKET);bool_();match(RIGHT_BRACKET);stmt();break; case DO_TKN: { printf("\nstmt->DO stmt while(bool)\n"); stmt(); match(WHILE_TKN); match(LEFT_BRACKET); bool_(); match(RIGHT_BRACKET); match(RELOP_SENI); break; } case BREAK_TKN: printf("\nstmt->BREAK ;\n"); match(BREAK_TKN),match(RELOP_TKN);break; default: printf("stmt->block"); block(); } }
2 stmts()函数
View Code
void stmts() { if(Lookahead==ID_TKN||Lookahead==IF_TKN||Lookahead==WHILE_TKN||Lookahead==DO_TKN||Lookahead==BREAK_TKN||Lookahead==LEFT_BIBRACKET)//first follow { printf(" stmts->stmt "); printf("stmts"); stmt(); stmts(); } else if(Lookahead==RIGHT_BIBRACKET) return; else printf(" stmts() error lookahead:%d\n",Lookahead); return; }
3 bool_()函数
View Code
void bool_(); void else_part() { if(Lookahead==ELSE_TKN) { printf("\nelse_part->else stmt;\n"); match(ELSE_TKN); } else { printf("\nelse_part->∞;\n"); return; } }
test1.l
View Code
%{ #include <stdio.h> #include <stdlib.h> #define ID_TKN 500 #define NUM_TKN 510 #define RELOP_TKN 520 #define RELOP_AD 521 #define RELOP_SU 522 #define RELOP_MU 523 #define RELOP_DI 524 #define RELOP_LT 525 #define RELOP_LE 526 #define RELOP_EQ 527 #define RELOP_NE 528 #define RELOP_GT 529 #define RELOP_GE 530 #define RELOP_SENI 531 #define RELOP_COMMA 532 #define LEFT_BRACKET 530 #define RIGHT_BRACKET 531 #define LEFT_MIBRACKET 532 #define RIGHT_MIBRACKET 533 #define LEFT_BIBRACKET 534 #define RIGHT_BIBRACKET 535 #define IF_TKN 610 #define WHILE_TKN 611 #define DO_TKN 612 #define BREAK_TKN 613 #define REAL_TKN 614 #define TRUE_TKN 615 #define FALSE_TKN 616 #define BASIC_TKN 617 #define ELSE_TKN 618 /*书上使用该变量yylval，但该变量不是flex自带的，所以我们要自己定义这个变量*/ int yylval; /*该函数可以将变量添加到符号表中，在这里我们没有实现该功能*/ int installID() ; /*该函数可以将数值添加到数值表中，在这里我们没有实现该功能*/ int installNum() ; /*请参考下面网页中的说明*/ /* http://www.ibm.com/developerworks/cn/linux/sdk/lex/index.html {explan} {printf("REMARK:%s\n",yytext);} */ %} delim [" "\t\n] ws {delim}+ letter [A-Za-z] digit [0-9] id {letter}({letter}|{digit})* number {digit}+(\.{digit}+)?(E[+-]?{digit}+)? explan \/\*.*\*\/ %% {ws} {/*no action and no return */ } if { printf("IF:%s\n",yytext); return (IF_TKN); } else { printf("ELSE:%s\n",yytext); return (ELSE_TKN); } while { printf("WHILE:%s\n",yytext); return (WHILE_TKN); } do { printf("DO:%s\n",yytext); return (DO_TKN); } break { printf("BREAK:%s\n",yytext); return (BREAK_TKN); } real { printf("REAL:%s\n",yytext); return (REAL_TKN); } true { printf("TRUE:%s\n",yytext); return (TRUE_TKN); } false { printf("FALSE:%s\n",yytext); return (FALSE_TKN); } int { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } char { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } bool { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } float { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } {explan} {printf("REMARK:%s\n",yytext);} {id} { yylval = (int) installID(); printf("ID:%s\n",yytext); return (ID_TKN); } {number} { yylval = (int) installNum();printf("Num:%d\n",yylval); return (NUM_TKN); } \( { yylval = LEFT_BRACKET; printf("LEFT_BRACKET:%s\n",yytext); return (LEFT_BRACKET); } \) { yylval = RIGHT_BRACKET; printf("RIGHT_BRACKET:%s\n",yytext); return (RIGHT_BRACKET); } \] { yylval = LEFT_MIBRACKET; printf("LEFT_MIBRACKET:%s\n",yytext); return (LEFT_MIBRACKET); } \[ { yylval = RIGHT_MIBRACKET; printf("RIGHT_MIBRACKET:%s\n",yytext); return (RIGHT_MIBRACKET); } \{ { yylval = LEFT_BIBRACKET; printf("LEFT_BIBRACKET:%s\n",yytext); return (LEFT_BIBRACKET); } \} { yylval = RIGHT_BIBRACKET; printf("RIGHT_BIBRACKET:%s\n",yytext); return (RIGHT_BIBRACKET); } ";" { yylval = RELOP_SENI; printf("SENI:%s\n",yytext); return(RELOP_TKN); } "," { yylval = RELOP_COMMA; printf("COMMA:%s\n",yytext); return(RELOP_TKN); } "+" { yylval = RELOP_AD; printf("AD:%s\n",yytext); return(RELOP_TKN); } "-" { yylval = RELOP_SU; printf("SU:%s\n",yytext); return(RELOP_TKN); } "*" { yylval = RELOP_MU; printf("MU:%s\n",yytext); return(RELOP_TKN); } "/" { yylval = RELOP_DI; printf("DI:%s\n",yytext); return(RELOP_TKN); } "<" { yylval = RELOP_LT; printf("LT:%s\n",yytext); return(RELOP_TKN); } "<=" { yylval = RELOP_LE; printf("LE:%s\n",yytext); return(RELOP_TKN); } "=" { yylval = RELOP_EQ; printf("EQ:%s\n",yytext); return(RELOP_TKN); } "!=" { yylval = RELOP_NE; printf("NE:%s\n",yytext); return(RELOP_TKN); } ">" { yylval = RELOP_GT; printf("GT:%s\n",yytext); return(RELOP_TKN); } ">=" { yylval = RELOP_GE; printf("GE:%s\n",yytext); return(RELOP_TKN); } %% /*该函数设置yyin变量，fflex对yyin变量所对应的文件进行词法分析*/ void BeginCompileOneFile( const char * filename ) { yyin = fopen( filename, "r"); fseek( yyin, 0, SEEK_SET ); } void EndCompileOneFile(void) { fclose(yyin); yyin = 0; } int yywrap()/*多文件*/ { return 1; } int exp() { return 1; } int installID() { return 1; } int installNum() { int tokenval=0; /*yytext*/ char *p=yytext; while(*p>='0'&&*p<='9') { tokenval=tokenval*10+*p-'0'; p++; } return tokenval ; } /* #ifdef __cplusplus extern "C" int yylex(void); extern "C" void BeginCompileOneFile( const char * filename ); extern "C" void EndCompileOneFile( void); #endif */ void main() { int token; char filename[1000]; printf("请输入要编译的源程序文件名："); gets(filename); BeginCompileOneFile( filename ); //当flex扫描到文件末尾，yylex函数返回0 while( ( token = yylex() ) > 0 ) ; EndCompileOneFile(); getchar(); }
main.cpp
View Code
#include<stdio.h> void parse(); void main() { printf("main\n"); parse(); }
paser.cpp
View Code
#include<stdio.h> #include"yytex.h" void yytex(); void BeginCompileOneFile( const char * filename ); void EndCompileOneFile(void); int yylex(void); void Expr(); int token; int Lookahead; extern char *yytext; //yytext 也就是现在获得的字符。 void program(); void parse() {//要先lookahean // int token; // char filename[1000]; printf("请输入要编译的源程序文件名："); //gets(filename); // BeginCompileOneFile( filename ); //当flex扫描到文件末尾，yylex函数返回0 // while( ( token = yylex() ) > 0 ) ; BeginCompileOneFile("a.txt"); Lookahead=yylex(); printf("program="); program();//函数调用 printf("\ngrogram end\n"); EndCompileOneFile(); //getchar(); } void match(int t) {//用来匹配字符 用已经定义的字符比如define if 500 如果match(if) 于是就是词法分析器获得了if 字符串。 //yylex为返回if字符串对应的500 是要return给yylex函数的。 yytext为if保存字符串的字符数组 yyval 是具体的符号， yylex是类符号 //match return后面的符号。 if(Lookahead==t) { Lookahead=yylex(); // printf(" %d ",Lookahead); } else printf("\nmatch() syntax error Lookahead:%d \n",Lookahead); } void block(); void program() { printf("\n program->block"); block(); } void stmts(); void block() { printf("\nblock->{ "); printf("stmts "); printf(" }\n"); match(LEFT_BIBRACKET); stmts(); match(RIGHT_BIBRACKET); return; } void stmt() { switch(Lookahead) { case ID_TKN: printf("\nstmt->ID=expr;\n"); match(ID_TKN);match(RELOP_TKN);Expr();match(RELOP_TKN);break; case IF_TKN: printf("\nstmt->IF(bool) stmt else_part \n"); match(IF_TKN);match(LEFT_BRACKET);bool_();match(RIGHT_BRACKET);stmt();match(ELSE_TKN);else_part();break; case WHILE_TKN: printf("\nstmt->WHILE (bool) stmt \n"); match(WHILE_TKN);match(LEFT_BRACKET);bool_();match(RIGHT_BRACKET);stmt();break; case DO_TKN: { printf("\nstmt->DO stmt while(bool)\n"); stmt(); match(WHILE_TKN); match(LEFT_BRACKET); bool_(); match(RIGHT_BRACKET); match(RELOP_SENI); break; } case BREAK_TKN: printf("\nstmt->BREAK ;\n"); match(BREAK_TKN),match(RELOP_TKN);break; default: printf("stmt->block"); block(); } } void bool_() { Expr(); switch(Lookahead){ case RELOP_TKN: printf("bool_->RELOP_TKN "); match(RELOP_TKN);Expr();break; default: break; /* switch(Lookahead){ case RELOP_LT: printf("\nbool_->LT "); match(RELOP_LT);Expr();break; case RELOP_LE: printf("\nbool_->LE "); match(RELOP_LE);Expr();break; case RELOP_GT: printf("\nbool_->GT "); match(RELOP_GT);Expr();break; case RELOP_GE: printf("\nbool_->GE "); match(RELOP_GE);Expr();break; default: match(520); match(510);*/ } } /*void Expr() { Expr(); switch(Lookahead){ case RELOP_AD: ; case RELOP_AD: }*/ void Factor() { /*switch( Lookahead ) { case '(': match('('); Expr(); match(')');break; default: match(Lookahead);break; }*/ if(Lookahead=='(') { match('('); Expr(); match(')'); } if(Lookahead==ID_TKN) //其中id_tkn与num_tkn为looahead的值 如何取得具体的值num值呢 { // printf("id "); // printf("%s\n",yytext); match(Lookahead); } if(Lookahead==NUM_TKN) { //printf("num "); //printf("%s\n",yytext); match(Lookahead); } // match(Lookahead); } void Morefactors(); void Term() { Factor(); Morefactors(); } void Morefactors() { switch( Lookahead ) { case '*': match('*'); Factor(); putchar('*'); Morefactors(); // rest --> + term {print('+')} rest break; case '/': match('/'); Term(); putchar('/'); Morefactors(); // rest --> - term {print('-')} rest break; default: // rest --> 空 break; } } void Moreterms() { switch( Lookahead ) { case '+': match('+'); Term(); putchar('+'); Moreterms(); // rest --> + term {print('+')} rest break; case '-': match('-'); Term(); putchar('-'); Moreterms(); // rest --> - term {print('-')} rest break; default: // rest --> 空 break; } } void Expr() { Term(); Moreterms(); }
yytex.cpp
View Code
/* A lexical scanner generated by flex */ /* Scanner skeleton version: * $Header: /home/daffy/u0/vern/flex/RCS/flex.skl,v 2.85 95/04/24 10:48:47 vern Exp $ */ #define FLEX_SCANNER #define YY_FLEX_MAJOR_VERSION 2 #define YY_FLEX_MINOR_VERSION 5 #include <stdio.h> #include"yytex.h" /* cfront 1.2 defines "c_plusplus" instead of "__cplusplus" */ #ifdef c_plusplus #ifndef __cplusplus #define __cplusplus #endif #endif #ifdef __cplusplus #include <stdlib.h> //#include <unistd.h> #ifndef _WIN32 #include <unistd.h> #else #ifndef YY_ALWAYS_INTERACTIVE #ifndef YY_NEVER_INTERACTIVE /* extern int isatty YY_PROTO(( int )); */ #include <io.h> #endif #endif #endif /* Use prototypes in function declarations. */ #define YY_USE_PROTOS /* The "const" storage-class-modifier is valid. */ #define YY_USE_CONST #else /* ! __cplusplus */ #if __STDC__ #define YY_USE_PROTOS #define YY_USE_CONST #endif /* __STDC__ */ #endif /* ! __cplusplus */ #ifdef __TURBOC__ #pragma warn -rch #pragma warn -use #include <io.h> #include <stdlib.h> #define YY_USE_CONST #define YY_USE_PROTOS #endif #ifdef YY_USE_CONST #define yyconst const #else #define yyconst #endif #ifdef YY_USE_PROTOS #define YY_PROTO(proto) proto #else #define YY_PROTO(proto) () #endif /* Returned upon end-of-file. */ #define YY_NULL 0 /* Promotes a possibly negative, possibly signed char to an unsigned * integer for use as an array index. If the signed char is negative, * we want to instead treat it as an 8-bit unsigned char, hence the * double cast. */ #define YY_SC_TO_UI(c) ((unsigned int) (unsigned char) c) /* Enter a start condition. This macro really ought to take a parameter, * but we do it the disgusting crufty way forced on us by the ()-less * definition of BEGIN. */ #define BEGIN yy_start = 1 + 2 * /* Translate the current start state into a value that can be later handed * to BEGIN to return to the state. The YYSTATE alias is for lex * compatibility. */ #define YY_START ((yy_start - 1) / 2) #define YYSTATE YY_START /* Action number for EOF rule of a given start state. */ #define YY_STATE_EOF(state) (YY_END_OF_BUFFER + state + 1) /* Special action meaning "start processing a new file". */ #define YY_NEW_FILE yyrestart( yyin ) #define YY_END_OF_BUFFER_CHAR 0 /* Size of default input buffer. */ #define YY_BUF_SIZE 16384 typedef struct yy_buffer_state *YY_BUFFER_STATE; extern int yyleng; extern FILE *yyin, *yyout; #define EOB_ACT_CONTINUE_SCAN 0 #define EOB_ACT_END_OF_FILE 1 #define EOB_ACT_LAST_MATCH 2 /* The funky do-while in the following #define is used to turn the definition * int a single C statement (which needs a semi-colon terminator). This * avoids problems with code like: * * if ( condition_holds ) * yyless( 5 ); * else * do_something_else(); * * Prior to using the do-while the compiler would get upset at the * "else" because it interpreted the "if" statement as being all * done when it reached the ';' after the yyless() call. */ /* Return all but the first 'n' matched characters back to the input stream. */ #define yyless(n) \ do \ { \ /* Undo effects of setting up yytext. */ \ *yy_cp = yy_hold_char; \ yy_c_buf_p = yy_cp = yy_bp + n - YY_MORE_ADJ; \ YY_DO_BEFORE_ACTION; /* set up yytext again */ \ } \ while ( 0 ) #define unput(c) yyunput( c, yytext_ptr ) /* The following is because we cannot portably get our hands on size_t * (without autoconf's help, which isn't available because we want * flex-generated scanners to compile on their own). */ typedef unsigned int yy_size_t; struct yy_buffer_state { FILE *yy_input_file; char *yy_ch_buf; /* input buffer */ char *yy_buf_pos; /* current position in input buffer */ /* Size of input buffer in bytes, not including room for EOB * characters. */ yy_size_t yy_buf_size; /* Number of characters read into yy_ch_buf, not including EOB * characters. */ int yy_n_chars; /* Whether we "own" the buffer - i.e., we know we created it, * and can realloc() it to grow it, and should free() it to * delete it. */ int yy_is_our_buffer; /* Whether this is an "interactive" input source; if so, and * if we're using stdio for input, then we want to use getc() * instead of fread(), to make sure we stop fetching input after * each newline. */ int yy_is_interactive; /* Whether we're considered to be at the beginning of a line. * If so, '^' rules will be active on the next match, otherwise * not. */ int yy_at_bol; /* Whether to try to fill the input buffer when we reach the * end of it. */ int yy_fill_buffer; int yy_buffer_status; #define YY_BUFFER_NEW 0 #define YY_BUFFER_NORMAL 1 /* When an EOF's been seen but there's still some text to process * then we mark the buffer as YY_EOF_PENDING, to indicate that we * shouldn't try reading from the input source any more. We might * still have a bunch of tokens to match, though, because of * possible backing-up. * * When we actually see the EOF, we change the status to "new" * (via yyrestart()), so that the user can continue scanning by * just pointing yyin at a new input file. */ #define YY_BUFFER_EOF_PENDING 2 }; static YY_BUFFER_STATE yy_current_buffer = 0; /* We provide macros for accessing buffer states in case in the * future we want to put the buffer states in a more general * "scanner state". */ #define YY_CURRENT_BUFFER yy_current_buffer /* yy_hold_char holds the character lost when yytext is formed. */ static char yy_hold_char; static int yy_n_chars; /* number of characters read into yy_ch_buf */ int yyleng; /* Points to current character in buffer. */ static char *yy_c_buf_p = (char *) 0; static int yy_init = 1; /* whether we need to initialize */ static int yy_start = 0; /* start state number */ /* Flag which is used to allow yywrap()'s to do buffer switches * instead of setting up a fresh yyin. A bit of a hack ... */ static int yy_did_buffer_switch_on_eof; void yyrestart YY_PROTO(( FILE *input_file )); void yy_switch_to_buffer YY_PROTO(( YY_BUFFER_STATE new_buffer )); void yy_load_buffer_state YY_PROTO(( void )); YY_BUFFER_STATE yy_create_buffer YY_PROTO(( FILE *file, int size )); void yy_delete_buffer YY_PROTO(( YY_BUFFER_STATE b )); void yy_init_buffer YY_PROTO(( YY_BUFFER_STATE b, FILE *file )); void yy_flush_buffer YY_PROTO(( YY_BUFFER_STATE b )); #define YY_FLUSH_BUFFER yy_flush_buffer( yy_current_buffer ) YY_BUFFER_STATE yy_scan_buffer YY_PROTO(( char *base, yy_size_t size )); YY_BUFFER_STATE yy_scan_string YY_PROTO(( yyconst char *str )); YY_BUFFER_STATE yy_scan_bytes YY_PROTO(( yyconst char *bytes, int len )); static void *yy_flex_alloc YY_PROTO(( yy_size_t )); static void *yy_flex_realloc YY_PROTO(( void *, yy_size_t )); static void yy_flex_free YY_PROTO(( void * )); #define yy_new_buffer yy_create_buffer #define yy_set_interactive(is_interactive) \ { \ if ( ! yy_current_buffer ) \ yy_current_buffer = yy_create_buffer( yyin, YY_BUF_SIZE ); \ yy_current_buffer->yy_is_interactive = is_interactive; \ } #define yy_set_bol(at_bol) \ { \ if ( ! yy_current_buffer ) \ yy_current_buffer = yy_create_buffer( yyin, YY_BUF_SIZE ); \ yy_current_buffer->yy_at_bol = at_bol; \ } #define YY_AT_BOL() (yy_current_buffer->yy_at_bol) typedef unsigned char YY_CHAR; FILE *yyin = (FILE *) 0, *yyout = (FILE *) 0; typedef int yy_state_type; extern char *yytext; #define yytext_ptr yytext static yy_state_type yy_get_previous_state YY_PROTO(( void )); static yy_state_type yy_try_NUL_trans YY_PROTO(( yy_state_type current_state )); static int yy_get_next_buffer YY_PROTO(( void )); static void yy_fatal_error YY_PROTO(( yyconst char msg[] )); /* Done after the current pattern has been matched and before the * corresponding action - sets up yytext. */ #define YY_DO_BEFORE_ACTION \ yytext_ptr = yy_bp; \ yyleng = (int) (yy_cp - yy_bp); \ yy_hold_char = *yy_cp; \ *yy_cp = '\0'; \ yy_c_buf_p = yy_cp; #define YY_NUM_RULES 35 #define YY_END_OF_BUFFER 36 static yyconst short int yy_accept[84] = { 0, 0, 0, 36, 35, 1, 35, 17, 18, 27, 25, 24, 26, 28, 16, 23, 29, 31, 33, 15, 20, 19, 15, 15, 15, 15, 15, 15, 15, 15, 15, 21, 22, 1, 32, 0, 0, 16, 0, 30, 34, 15, 15, 15, 15, 5, 15, 15, 15, 2, 15, 15, 15, 15, 0, 0, 16, 0, 16, 15, 15, 15, 15, 15, 15, 10, 15, 15, 15, 14, 12, 15, 11, 3, 15, 15, 7, 8, 15, 6, 9, 13, 4, 0 } ; static yyconst int yy_ec[256] = { 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 4, 2, 1, 1, 1, 1, 1, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 1, 14, 15, 16, 17, 1, 1, 18, 18, 18, 18, 19, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 20, 1, 21, 1, 1, 1, 22, 23, 24, 25, 26, 27, 18, 28, 29, 18, 30, 31, 18, 32, 33, 18, 18, 34, 35, 36, 37, 18, 38, 18, 18, 18, 39, 1, 40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 } ; static yyconst int yy_meta[41] = { 0, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 3, 3, 1, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1 } ; static yyconst short int yy_base[86] = { 0, 0, 0, 106, 107, 39, 89, 107, 107, 107, 107, 107, 107, 97, 32, 107, 87, 107, 86, 0, 107, 107, 13, 73, 67, 68, 22, 22, 72, 63, 68, 107, 107, 53, 107, 88, 81, 39, 49, 107, 107, 0, 60, 66, 69, 0, 55, 58, 55, 0, 51, 64, 48, 55, 76, 53, 48, 69, 68, 49, 57, 44, 51, 41, 53, 0, 43, 47, 41, 64, 0, 39, 0, 0, 40, 28, 0, 0, 37, 0, 0, 0, 0, 107, 45, 67 } ; static yyconst short int yy_def[86] = { 0, 83, 1, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 84, 83, 83, 84, 84, 84, 84, 84, 84, 84, 84, 84, 83, 83, 83, 83, 85, 83, 83, 83, 83, 83, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 85, 85, 83, 83, 83, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 85, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 0, 83, 83 } ; static yyconst short int yy_nxt[148] = { 0, 4, 5, 5, 6, 7, 8, 9, 10, 11, 12, 4, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 19, 22, 23, 24, 25, 26, 19, 27, 19, 19, 19, 19, 28, 19, 29, 19, 30, 31, 32, 33, 33, 36, 47, 37, 42, 43, 41, 49, 36, 38, 37, 48, 50, 33, 33, 57, 38, 57, 55, 56, 58, 82, 81, 69, 80, 38, 54, 79, 54, 55, 78, 77, 76, 75, 74, 73, 72, 71, 70, 58, 58, 55, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 56, 55, 53, 52, 51, 46, 45, 44, 40, 39, 35, 34, 83, 3, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83 } ; static yyconst short int yy_chk[148] = { 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 5, 14, 26, 14, 22, 22, 84, 27, 37, 14, 37, 26, 27, 33, 33, 38, 37, 38, 55, 56, 38, 78, 75, 55, 74, 56, 85, 71, 85, 69, 68, 67, 66, 64, 63, 62, 61, 60, 59, 58, 57, 54, 53, 52, 51, 50, 48, 47, 46, 44, 43, 42, 36, 35, 30, 29, 28, 25, 24, 23, 18, 16, 13, 6, 3, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83 } ; static yy_state_type yy_last_accepting_state; static char *yy_last_accepting_cpos; /* The intent behind this definition is that it'll catch * any uses of REJECT which flex missed. */ #define REJECT reject_used_but_not_detected #define yymore() yymore_used_but_not_detected #define YY_MORE_ADJ 0 char *yytext; #line 1 "test.1" #define INITIAL 0 #line 3 "test.1" #include <stdio.h> #include <stdlib.h> /*书上使用该变量yylval，但该变量不是flex自带的，所以我们要自己定义这个变量*/ int yylval; /*该函数可以将变量添加到符号表中，在这里我们没有实现该功能*/ int installID() ; /*该函数可以将数值添加到数值表中，在这里我们没有实现该功能*/ int installNum() ; /*请参考下面网页中的说明*/ /* http://www.ibm.com/developerworks/cn/linux/sdk/lex/index.html {explan} {printf("REMARK:%s\n",yytext);} */ #line 470 "lex.yy.c" /* Macros after this point can all be overridden by user definitions in * section 1. */ #ifndef YY_SKIP_YYWRAP #ifdef __cplusplus extern "C" int yywrap YY_PROTO(( void )); #else extern int yywrap YY_PROTO(( void )); #endif #endif #ifndef YY_NO_UNPUT static void yyunput YY_PROTO(( int c, char *buf_ptr )); #endif #ifndef yytext_ptr static void yy_flex_strncpy YY_PROTO(( char *, yyconst char *, int )); #endif #ifndef YY_NO_INPUT #ifdef __cplusplus static int yyinput YY_PROTO(( void )); #else static int input YY_PROTO(( void )); #endif #endif #if YY_STACK_USED static int yy_start_stack_ptr = 0; static int yy_start_stack_depth = 0; static int *yy_start_stack = 0; #ifndef YY_NO_PUSH_STATE static void yy_push_state YY_PROTO(( int new_state )); #endif #ifndef YY_NO_POP_STATE static void yy_pop_state YY_PROTO(( void )); #endif #ifndef YY_NO_TOP_STATE static int yy_top_state YY_PROTO(( void )); #endif #else #define YY_NO_PUSH_STATE 1 #define YY_NO_POP_STATE 1 #define YY_NO_TOP_STATE 1 #endif #ifdef YY_MALLOC_DECL YY_MALLOC_DECL #else #if __STDC__ #ifndef __cplusplus #include <stdlib.h> #endif #else /* Just try to get by without declaring the routines. This will fail * miserably on non-ANSI systems for which sizeof(size_t) != sizeof(int) * or sizeof(void*) != sizeof(int). */ #endif #endif /* Amount of stuff to slurp up with each read. */ #ifndef YY_READ_BUF_SIZE #define YY_READ_BUF_SIZE 8192 #endif /* Copy whatever the last rule matched to the standard output. */ #ifndef ECHO /* This used to be an fputs(), but since the string might contain NUL's, * we now use fwrite(). */ #define ECHO (void) fwrite( yytext, yyleng, 1, yyout ) #endif /* Gets input and stuffs it into "buf". number of characters read, or YY_NULL, * is returned in "result". */ #ifndef YY_INPUT #define YY_INPUT(buf,result,max_size) \ if ( yy_current_buffer->yy_is_interactive ) \ { \ int c = '*', n; \ for ( n = 0; n < max_size && \ (c = getc( yyin )) != EOF && c != '\n'; ++n ) \ buf[n] = (char) c; \ if ( c == '\n' ) \ buf[n++] = (char) c; \ if ( c == EOF && ferror( yyin ) ) \ YY_FATAL_ERROR( "input in flex scanner failed" ); \ result = n; \ } \ else if ( ((result = fread( buf, 1, max_size, yyin )) == 0) \ && ferror( yyin ) ) \ YY_FATAL_ERROR( "input in flex scanner failed" ); #endif /* No semi-colon after return; correct usage is to write "yyterminate();" - * we don't want an extra ';' after the "return" because that will cause * some compilers to complain about unreachable statements. */ #ifndef yyterminate #define yyterminate() return YY_NULL #endif /* Number of entries by which start-condition stack grows. */ #ifndef YY_START_STACK_INCR #define YY_START_STACK_INCR 25 #endif /* Report a fatal error. */ #ifndef YY_FATAL_ERROR #define YY_FATAL_ERROR(msg) yy_fatal_error( msg ) #endif /* Default declaration of generated scanner - a define so the user can * easily add parameters. */ #ifndef YY_DECL #define YY_DECL int yylex YY_PROTO(( void )) #endif /* Code executed at the beginning of each rule, after yytext and yyleng * have been set up. */ #ifndef YY_USER_ACTION #define YY_USER_ACTION #endif /* Code executed at the end of each rule. */ #ifndef YY_BREAK #define YY_BREAK break; #endif #define YY_RULE_SETUP \ YY_USER_ACTION YY_DECL { register yy_state_type yy_current_state; register char *yy_cp, *yy_bp; register int yy_act; #line 63 "test.1" #line 620 "lex.yy.c" if ( yy_init ) { yy_init = 0; #ifdef YY_USER_INIT YY_USER_INIT; #endif if ( ! yy_start ) yy_start = 1; /* first start state */ if ( ! yyin ) yyin = stdin; if ( ! yyout ) yyout = stdout; if ( ! yy_current_buffer ) yy_current_buffer = yy_create_buffer( yyin, YY_BUF_SIZE ); yy_load_buffer_state(); } while ( 1 ) /* loops until end-of-file is reached */ { yy_cp = yy_c_buf_p; /* Support of yytext. */ *yy_cp = yy_hold_char; /* yy_bp points to the position in yy_ch_buf of the start of * the current run. */ yy_bp = yy_cp; yy_current_state = yy_start; yy_match: do { register YY_CHAR yy_c = yy_ec[YY_SC_TO_UI(*yy_cp)]; if ( yy_accept[yy_current_state] ) { yy_last_accepting_state = yy_current_state; yy_last_accepting_cpos = yy_cp; } while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state ) { yy_current_state = (int) yy_def[yy_current_state]; if ( yy_current_state >= 84 ) yy_c = yy_meta[(unsigned int) yy_c]; } yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c]; ++yy_cp; } while ( yy_base[yy_current_state] != 107 ); yy_find_action: yy_act = yy_accept[yy_current_state]; if ( yy_act == 0 ) { /* have to back up */ yy_cp = yy_last_accepting_cpos; yy_current_state = yy_last_accepting_state; yy_act = yy_accept[yy_current_state]; } YY_DO_BEFORE_ACTION; do_action: /* This label is used only to access EOF actions. */ switch ( yy_act ) { /* beginning of action switch */ case 0: /* must back up */ /* undo the effects of YY_DO_BEFORE_ACTION */ *yy_cp = yy_hold_char; yy_cp = yy_last_accepting_cpos; yy_current_state = yy_last_accepting_state; goto yy_find_action; case 1: YY_RULE_SETUP #line 65 "test.1" {/*no action and no return */ } YY_BREAK case 2: YY_RULE_SETUP #line 66 "test.1" { printf("IF:%s\n",yytext); return (IF_TKN); } YY_BREAK case 3: YY_RULE_SETUP #line 67 "test.1" { printf("ELSE:%s\n",yytext); return (ELSE_TKN); } YY_BREAK case 4: YY_RULE_SETUP #line 68 "test.1" { printf("WHILE:%s\n",yytext); return (WHILE_TKN); } YY_BREAK case 5: YY_RULE_SETUP #line 69 "test.1" { printf("DO:%s\n",yytext); return (DO_TKN); } YY_BREAK case 6: YY_RULE_SETUP #line 70 "test.1" { printf("BREAK:%s\n",yytext); return (BREAK_TKN); } YY_BREAK case 7: YY_RULE_SETUP #line 71 "test.1" { printf("REAL:%s\n",yytext); return (REAL_TKN); } YY_BREAK case 8: YY_RULE_SETUP #line 72 "test.1" { printf("TRUE:%s\n",yytext); return (TRUE_TKN); } YY_BREAK case 9: YY_RULE_SETUP #line 73 "test.1" { printf("FALSE:%s\n",yytext); return (FALSE_TKN); } YY_BREAK case 10: YY_RULE_SETUP #line 74 "test.1" { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } YY_BREAK case 11: YY_RULE_SETUP #line 75 "test.1" { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } YY_BREAK case 12: YY_RULE_SETUP #line 76 "test.1" { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } YY_BREAK case 13: YY_RULE_SETUP #line 77 "test.1" { printf("BASIC:%s\n",yytext); return (BASIC_TKN); } YY_BREAK case 14: YY_RULE_SETUP #line 80 "test.1" {printf("REMARK:%s\n",yytext);} YY_BREAK case 15: YY_RULE_SETUP #line 81 "test.1" { yylval = (int) installID(); printf("ID:%s\n",yytext); return (ID_TKN); } YY_BREAK case 16: YY_RULE_SETUP #line 82 "test.1" { yylval = (int) installNum();printf("Num:%d\n",yylval); return (NUM_TKN); } YY_BREAK case 17: YY_RULE_SETUP #line 84 "test.1" { yylval = LEFT_BRACKET; printf("LEFT_BRACKET:%s\n",yytext); return (LEFT_BRACKET); } YY_BREAK case 18: YY_RULE_SETUP #line 85 "test.1" { yylval = RIGHT_BRACKET; printf("RIGHT_BRACKET:%s\n",yytext); return (RIGHT_BRACKET); } YY_BREAK case 19: YY_RULE_SETUP #line 86 "test.1" { yylval = LEFT_MIBRACKET; printf("LEFT_MIBRACKET:%s\n",yytext); return (LEFT_MIBRACKET); } YY_BREAK case 20: YY_RULE_SETUP #line 87 "test.1" { yylval = RIGHT_MIBRACKET; printf("RIGHT_MIBRACKET:%s\n",yytext); return (RIGHT_MIBRACKET); } YY_BREAK case 21: YY_RULE_SETUP #line 88 "test.1" { yylval = LEFT_BIBRACKET; printf("LEFT_BIBRACKET:%s\n",yytext); return (LEFT_BIBRACKET); } YY_BREAK case 22: YY_RULE_SETUP #line 89 "test.1" { yylval = RIGHT_BIBRACKET; printf("RIGHT_BIBRACKET:%s\n",yytext); return (RIGHT_BIBRACKET); } YY_BREAK case 23: YY_RULE_SETUP #line 92 "test.1" { yylval = RELOP_SENI; printf("SENI:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 24: YY_RULE_SETUP #line 93 "test.1" { yylval = RELOP_COMMA; printf("COMMA:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 25: YY_RULE_SETUP #line 94 "test.1" { yylval = RELOP_AD; printf("AD:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 26: YY_RULE_SETUP #line 95 "test.1" { yylval = RELOP_SU; printf("SU:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 27: YY_RULE_SETUP #line 96 "test.1" { yylval = RELOP_MU; printf("MU:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 28: YY_RULE_SETUP #line 97 "test.1" { yylval = RELOP_DI; printf("DI:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 29: YY_RULE_SETUP #line 98 "test.1" { yylval = RELOP_LT; printf("LT:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 30: YY_RULE_SETUP #line 99 "test.1" { yylval = RELOP_LE; printf("LE:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 31: YY_RULE_SETUP #line 100 "test.1" { yylval = RELOP_EQ; printf("EQ:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 32: YY_RULE_SETUP #line 101 "test.1" { yylval = RELOP_NE; printf("NE:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 33: YY_RULE_SETUP #line 102 "test.1" { yylval = RELOP_GT; printf("GT:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 34: YY_RULE_SETUP #line 103 "test.1" { yylval = RELOP_GE; printf("GE:%s\n",yytext); return(RELOP_TKN); } YY_BREAK case 35: YY_RULE_SETUP #line 106 "test.1" ECHO; YY_BREAK #line 878 "lex.yy.c" case YY_STATE_EOF(INITIAL): yyterminate(); case YY_END_OF_BUFFER: { /* Amount of text matched not including the EOB char. */ int yy_amount_of_matched_text = (int) (yy_cp - yytext_ptr) - 1; /* Undo the effects of YY_DO_BEFORE_ACTION. */ *yy_cp = yy_hold_char; if ( yy_current_buffer->yy_buffer_status == YY_BUFFER_NEW ) { /* We're scanning a new file or input source. It's * possible that this happened because the user * just pointed yyin at a new source and called * yylex(). If so, then we have to assure * consistency between yy_current_buffer and our * globals. Here is the right place to do so, because * this is the first action (other than possibly a * back-up) that will match for the new input source. */ yy_n_chars = yy_current_buffer->yy_n_chars; yy_current_buffer->yy_input_file = yyin; yy_current_buffer->yy_buffer_status = YY_BUFFER_NORMAL; } /* Note that here we test for yy_c_buf_p "<=" to the position * of the first EOB in the buffer, since yy_c_buf_p will * already have been incremented past the NUL character * (since all states make transitions on EOB to the * end-of-buffer state). Contrast this with the test * in input(). */ if ( yy_c_buf_p <= &yy_current_buffer->yy_ch_buf[yy_n_chars] ) { /* This was really a NUL. */ yy_state_type yy_next_state; yy_c_buf_p = yytext_ptr + yy_amount_of_matched_text; yy_current_state = yy_get_previous_state(); /* Okay, we're now positioned to make the NUL * transition. We couldn't have * yy_get_previous_state() go ahead and do it * for us because it doesn't know how to deal * with the possibility of jamming (and we don't * want to build jamming into it because then it * will run more slowly). */ yy_next_state = yy_try_NUL_trans( yy_current_state ); yy_bp = yytext_ptr + YY_MORE_ADJ; if ( yy_next_state ) { /* Consume the NUL. */ yy_cp = ++yy_c_buf_p; yy_current_state = yy_next_state; goto yy_match; } else { yy_cp = yy_c_buf_p; goto yy_find_action; } } else switch ( yy_get_next_buffer() ) { case EOB_ACT_END_OF_FILE: { yy_did_buffer_switch_on_eof = 0; if ( yywrap() ) { /* Note: because we've taken care in * yy_get_next_buffer() to have set up * yytext, we can now set up * yy_c_buf_p so that if some total * hoser (like flex itself) wants to * call the scanner after we return the * YY_NULL, it'll still work - another * YY_NULL will get returned. */ yy_c_buf_p = yytext_ptr + YY_MORE_ADJ; yy_act = YY_STATE_EOF(YY_START); goto do_action; } else { if ( ! yy_did_buffer_switch_on_eof ) YY_NEW_FILE; } break; } case EOB_ACT_CONTINUE_SCAN: yy_c_buf_p = yytext_ptr + yy_amount_of_matched_text; yy_current_state = yy_get_previous_state(); yy_cp = yy_c_buf_p; yy_bp = yytext_ptr + YY_MORE_ADJ; goto yy_match; case EOB_ACT_LAST_MATCH: yy_c_buf_p = &yy_current_buffer->yy_ch_buf[yy_n_chars]; yy_current_state = yy_get_previous_state(); yy_cp = yy_c_buf_p; yy_bp = yytext_ptr + YY_MORE_ADJ; goto yy_find_action; } break; } default: YY_FATAL_ERROR( "fatal flex scanner internal error--no action found" ); } /* end of action switch */ } /* end of scanning one token */ } /* end of yylex */ /* yy_get_next_buffer - try to read in a new buffer * * Returns a code representing an action: * EOB_ACT_LAST_MATCH - * EOB_ACT_CONTINUE_SCAN - continue scanning from current position * EOB_ACT_END_OF_FILE - end of file */ static int yy_get_next_buffer() { register char *dest = yy_current_buffer->yy_ch_buf; register char *source = yytext_ptr; register int number_to_move, i; int ret_val; if ( yy_c_buf_p > &yy_current_buffer->yy_ch_buf[yy_n_chars + 1] ) YY_FATAL_ERROR( "fatal flex scanner internal error--end of buffer missed" ); if ( yy_current_buffer->yy_fill_buffer == 0 ) { /* Don't try to fill the buffer, so this is an EOF. */ if ( yy_c_buf_p - yytext_ptr - YY_MORE_ADJ == 1 ) { /* We matched a singled characater, the EOB, so * treat this as a final EOF. */ return EOB_ACT_END_OF_FILE; } else { /* We matched some text prior to the EOB, first * process it. */ return EOB_ACT_LAST_MATCH; } } /* Try to read more data. */ /* First move last chars to start of buffer. */ number_to_move = (int) (yy_c_buf_p - yytext_ptr) - 1; for ( i = 0; i < number_to_move; ++i ) *(dest++) = *(source++); if ( yy_current_buffer->yy_buffer_status == YY_BUFFER_EOF_PENDING ) /* don't do the read, it's not guaranteed to return an EOF, * just force an EOF */ yy_n_chars = 0; else { int num_to_read = yy_current_buffer->yy_buf_size - number_to_move - 1; while ( num_to_read <= 0 ) { /* Not enough room in the buffer - grow it. */ #ifdef YY_USES_REJECT YY_FATAL_ERROR( "input buffer overflow, can't enlarge buffer because scanner uses REJECT" ); #else /* just a shorter name for the current buffer */ YY_BUFFER_STATE b = yy_current_buffer; int yy_c_buf_p_offset = (int) (yy_c_buf_p - b->yy_ch_buf); if ( b->yy_is_our_buffer ) { int new_size = b->yy_buf_size * 2; if ( new_size <= 0 ) b->yy_buf_size += b->yy_buf_size / 8; else b->yy_buf_size *= 2; b->yy_ch_buf = (char *) /* Include room in for 2 EOB chars. */ yy_flex_realloc( (void *) b->yy_ch_buf, b->yy_buf_size + 2 ); } else /* Can't grow it, we don't own it. */ b->yy_ch_buf = 0; if ( ! b->yy_ch_buf ) YY_FATAL_ERROR( "fatal error - scanner input buffer overflow" ); yy_c_buf_p = &b->yy_ch_buf[yy_c_buf_p_offset]; num_to_read = yy_current_buffer->yy_buf_size - number_to_move - 1; #endif } if ( num_to_read > YY_READ_BUF_SIZE ) num_to_read = YY_READ_BUF_SIZE; /* Read in more data. */ YY_INPUT( (&yy_current_buffer->yy_ch_buf[number_to_move]), yy_n_chars, num_to_read ); } if ( yy_n_chars == 0 ) { if ( number_to_move == YY_MORE_ADJ ) { ret_val = EOB_ACT_END_OF_FILE; yyrestart( yyin ); } else { ret_val = EOB_ACT_LAST_MATCH; yy_current_buffer->yy_buffer_status = YY_BUFFER_EOF_PENDING; } } else ret_val = EOB_ACT_CONTINUE_SCAN; yy_n_chars += number_to_move; yy_current_buffer->yy_ch_buf[yy_n_chars] = YY_END_OF_BUFFER_CHAR; yy_current_buffer->yy_ch_buf[yy_n_chars + 1] = YY_END_OF_BUFFER_CHAR; yytext_ptr = &yy_current_buffer->yy_ch_buf[0]; return ret_val; } /* yy_get_previous_state - get the state just before the EOB char was reached */ static yy_state_type yy_get_previous_state() { register yy_state_type yy_current_state; register char *yy_cp; yy_current_state = yy_start; for ( yy_cp = yytext_ptr + YY_MORE_ADJ; yy_cp < yy_c_buf_p; ++yy_cp ) { register YY_CHAR yy_c = (*yy_cp ? yy_ec[YY_SC_TO_UI(*yy_cp)] : 1); if ( yy_accept[yy_current_state] ) { yy_last_accepting_state = yy_current_state; yy_last_accepting_cpos = yy_cp; } while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state ) { yy_current_state = (int) yy_def[yy_current_state]; if ( yy_current_state >= 84 ) yy_c = yy_meta[(unsigned int) yy_c]; } yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c]; } return yy_current_state; } /* yy_try_NUL_trans - try to make a transition on the NUL character * * synopsis * next_state = yy_try_NUL_trans( current_state ); */ #ifdef YY_USE_PROTOS static yy_state_type yy_try_NUL_trans( yy_state_type yy_current_state ) #else static yy_state_type yy_try_NUL_trans( yy_current_state ) yy_state_type yy_current_state; #endif { register int yy_is_jam; register char *yy_cp = yy_c_buf_p; register YY_CHAR yy_c = 1; if ( yy_accept[yy_current_state] ) { yy_last_accepting_state = yy_current_state; yy_last_accepting_cpos = yy_cp; } while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state ) { yy_current_state = (int) yy_def[yy_current_state]; if ( yy_current_state >= 84 ) yy_c = yy_meta[(unsigned int) yy_c]; } yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c]; yy_is_jam = (yy_current_state == 83); return yy_is_jam ? 0 : yy_current_state; } #ifndef YY_NO_UNPUT #ifdef YY_USE_PROTOS static void yyunput( int c, register char *yy_bp ) #else static void yyunput( c, yy_bp ) int c; register char *yy_bp; #endif { register char *yy_cp = yy_c_buf_p; /* undo effects of setting up yytext */ *yy_cp = yy_hold_char; if ( yy_cp < yy_current_buffer->yy_ch_buf + 2 ) { /* need to shift things up to make room */ /* +2 for EOB chars. */ register int number_to_move = yy_n_chars + 2; register char *dest = &yy_current_buffer->yy_ch_buf[ yy_current_buffer->yy_buf_size + 2]; register char *source = &yy_current_buffer->yy_ch_buf[number_to_move]; while ( source > yy_current_buffer->yy_ch_buf ) *--dest = *--source; yy_cp += (int) (dest - source); yy_bp += (int) (dest - source); yy_n_chars = yy_current_buffer->yy_buf_size; if ( yy_cp < yy_current_buffer->yy_ch_buf + 2 ) YY_FATAL_ERROR( "flex scanner push-back overflow" ); } *--yy_cp = (char) c; yytext_ptr = yy_bp; yy_hold_char = *yy_cp; yy_c_buf_p = yy_cp; } #endif /* ifndef YY_NO_UNPUT */ #ifdef __cplusplus static int yyinput() #else static int input() #endif { int c; *yy_c_buf_p = yy_hold_char; if ( *yy_c_buf_p == YY_END_OF_BUFFER_CHAR ) { /* yy_c_buf_p now points to the character we want to return. * If this occurs *before* the EOB characters, then it's a * valid NUL; if not, then we've hit the end of the buffer. */ if ( yy_c_buf_p < &yy_current_buffer->yy_ch_buf[yy_n_chars] ) /* This was really a NUL. */ *yy_c_buf_p = '\0'; else { /* need more input */ yytext_ptr = yy_c_buf_p; ++yy_c_buf_p; switch ( yy_get_next_buffer() ) { case EOB_ACT_END_OF_FILE: { if ( yywrap() ) { yy_c_buf_p = yytext_ptr + YY_MORE_ADJ; return EOF; } if ( ! yy_did_buffer_switch_on_eof ) YY_NEW_FILE; #ifdef __cplusplus return yyinput(); #else return input(); #endif } case EOB_ACT_CONTINUE_SCAN: yy_c_buf_p = yytext_ptr + YY_MORE_ADJ; break; case EOB_ACT_LAST_MATCH: #ifdef __cplusplus YY_FATAL_ERROR( "unexpected last match in yyinput()" ); #else YY_FATAL_ERROR( "unexpected last match in input()" ); #endif } } } c = *(unsigned char *) yy_c_buf_p; /* cast for 8-bit char's */ *yy_c_buf_p = '\0'; /* preserve yytext */ yy_hold_char = *++yy_c_buf_p; return c; } #ifdef YY_USE_PROTOS void yyrestart( FILE *input_file ) #else void yyrestart( input_file ) FILE *input_file; #endif { if ( ! yy_current_buffer ) yy_current_buffer = yy_create_buffer( yyin, YY_BUF_SIZE ); yy_init_buffer( yy_current_buffer, input_file ); yy_load_buffer_state(); } #ifdef YY_USE_PROTOS void yy_switch_to_buffer( YY_BUFFER_STATE new_buffer ) #else void yy_switch_to_buffer( new_buffer ) YY_BUFFER_STATE new_buffer; #endif { if ( yy_current_buffer == new_buffer ) return; if ( yy_current_buffer ) { /* Flush out information for old buffer. */ *yy_c_buf_p = yy_hold_char; yy_current_buffer->yy_buf_pos = yy_c_buf_p; yy_current_buffer->yy_n_chars = yy_n_chars; } yy_current_buffer = new_buffer; yy_load_buffer_state(); /* We don't actually know whether we did this switch during * EOF (yywrap()) processing, but the only time this flag * is looked at is after yywrap() is called, so it's safe * to go ahead and always set it. */ yy_did_buffer_switch_on_eof = 1; } #ifdef YY_USE_PROTOS void yy_load_buffer_state( void ) #else void yy_load_buffer_state() #endif { yy_n_chars = yy_current_buffer->yy_n_chars; yytext_ptr = yy_c_buf_p = yy_current_buffer->yy_buf_pos; yyin = yy_current_buffer->yy_input_file; yy_hold_char = *yy_c_buf_p; } #ifdef YY_USE_PROTOS YY_BUFFER_STATE yy_create_buffer( FILE *file, int size ) #else YY_BUFFER_STATE yy_create_buffer( file, size ) FILE *file; int size; #endif { YY_BUFFER_STATE b; b = (YY_BUFFER_STATE) yy_flex_alloc( sizeof( struct yy_buffer_state ) ); if ( ! b ) YY_FATAL_ERROR( "out of dynamic memory in yy_create_buffer()" ); b->yy_buf_size = size; /* yy_ch_buf has to be 2 characters longer than the size given because * we need to put in 2 end-of-buffer characters. */ b->yy_ch_buf = (char *) yy_flex_alloc( b->yy_buf_size + 2 ); if ( ! b->yy_ch_buf ) YY_FATAL_ERROR( "out of dynamic memory in yy_create_buffer()" ); b->yy_is_our_buffer = 1; yy_init_buffer( b, file ); return b; } #ifdef YY_USE_PROTOS void yy_delete_buffer( YY_BUFFER_STATE b ) #else void yy_delete_buffer( b ) YY_BUFFER_STATE b; #endif { if ( ! b ) return; if ( b == yy_current_buffer ) yy_current_buffer = (YY_BUFFER_STATE) 0; if ( b->yy_is_our_buffer ) yy_flex_free( (void *) b->yy_ch_buf ); yy_flex_free( (void *) b ); } #ifndef YY_ALWAYS_INTERACTIVE #ifndef YY_NEVER_INTERACTIVE extern int isatty YY_PROTO(( int )); #endif #endif #ifdef YY_USE_PROTOS void yy_init_buffer( YY_BUFFER_STATE b, FILE *file ) #else void yy_init_buffer( b, file ) YY_BUFFER_STATE b; FILE *file; #endif { yy_flush_buffer( b ); b->yy_input_file = file; b->yy_fill_buffer = 1; #if YY_ALWAYS_INTERACTIVE b->yy_is_interactive = 1; #else #if YY_NEVER_INTERACTIVE b->yy_is_interactive = 0; #else b->yy_is_interactive = file ? (isatty( fileno(file) ) > 0) : 0; #endif #endif } #ifdef YY_USE_PROTOS void yy_flush_buffer( YY_BUFFER_STATE b ) #else void yy_flush_buffer( b ) YY_BUFFER_STATE b; #endif { b->yy_n_chars = 0; /* We always need two end-of-buffer characters. The first causes * a transition to the end-of-buffer state. The second causes * a jam in that state. */ b->yy_ch_buf[0] = YY_END_OF_BUFFER_CHAR; b->yy_ch_buf[1] = YY_END_OF_BUFFER_CHAR; b->yy_buf_pos = &b->yy_ch_buf[0]; b->yy_at_bol = 1; b->yy_buffer_status = YY_BUFFER_NEW; if ( b == yy_current_buffer ) yy_load_buffer_state(); } #ifndef YY_NO_SCAN_BUFFER #ifdef YY_USE_PROTOS YY_BUFFER_STATE yy_scan_buffer( char *base, yy_size_t size ) #else YY_BUFFER_STATE yy_scan_buffer( base, size ) char *base; yy_size_t size; #endif { YY_BUFFER_STATE b; if ( size < 2 || base[size-2] != YY_END_OF_BUFFER_CHAR || base[size-1] != YY_END_OF_BUFFER_CHAR ) /* They forgot to leave room for the EOB's. */ return 0; b = (YY_BUFFER_STATE) yy_flex_alloc( sizeof( struct yy_buffer_state ) ); if ( ! b ) YY_FATAL_ERROR( "out of dynamic memory in yy_scan_buffer()" ); b->yy_buf_size = size - 2; /* "- 2" to take care of EOB's */ b->yy_buf_pos = b->yy_ch_buf = base; b->yy_is_our_buffer = 0; b->yy_input_file = 0; b->yy_n_chars = b->yy_buf_size; b->yy_is_interactive = 0; b->yy_at_bol = 1; b->yy_fill_buffer = 0; b->yy_buffer_status = YY_BUFFER_NEW; yy_switch_to_buffer( b ); return b; } #endif #ifndef YY_NO_SCAN_STRING #ifdef YY_USE_PROTOS YY_BUFFER_STATE yy_scan_string( yyconst char *str ) #else YY_BUFFER_STATE yy_scan_string( str ) yyconst char *str; #endif { int len; for ( len = 0; str[len]; ++len ) ; return yy_scan_bytes( str, len ); } #endif #ifndef YY_NO_SCAN_BYTES #ifdef YY_USE_PROTOS YY_BUFFER_STATE yy_scan_bytes( yyconst char *bytes, int len ) #else YY_BUFFER_STATE yy_scan_bytes( bytes, len ) yyconst char *bytes; int len; #endif { YY_BUFFER_STATE b; char *buf; yy_size_t n; int i; /* Get memory for full buffer, including space for trailing EOB's. */ n = len + 2; buf = (char *) yy_flex_alloc( n ); if ( ! buf ) YY_FATAL_ERROR( "out of dynamic memory in yy_scan_bytes()" ); for ( i = 0; i < len; ++i ) buf[i] = bytes[i]; buf[len] = buf[len+1] = YY_END_OF_BUFFER_CHAR; b = yy_scan_buffer( buf, n ); if ( ! b ) YY_FATAL_ERROR( "bad buffer in yy_scan_bytes()" ); /* It's okay to grow etc. this buffer, and we should throw it * away when we're done. */ b->yy_is_our_buffer = 1; return b; } #endif #ifndef YY_NO_PUSH_STATE #ifdef YY_USE_PROTOS static void yy_push_state( int new_state ) #else static void yy_push_state( new_state ) int new_state; #endif { if ( yy_start_stack_ptr >= yy_start_stack_depth ) { yy_size_t new_size; yy_start_stack_depth += YY_START_STACK_INCR; new_size = yy_start_stack_depth * sizeof( int ); if ( ! yy_start_stack ) yy_start_stack = (int *) yy_flex_alloc( new_size ); else yy_start_stack = (int *) yy_flex_realloc( (void *) yy_start_stack, new_size ); if ( ! yy_start_stack ) YY_FATAL_ERROR( "out of memory expanding start-condition stack" ); } yy_start_stack[yy_start_stack_ptr++] = YY_START; BEGIN(new_state); } #endif #ifndef YY_NO_POP_STATE static void yy_pop_state() { if ( --yy_start_stack_ptr < 0 ) YY_FATAL_ERROR( "start-condition stack underflow" ); BEGIN(yy_start_stack[yy_start_stack_ptr]); } #endif #ifndef YY_NO_TOP_STATE static int yy_top_state() { return yy_start_stack[yy_start_stack_ptr - 1]; } #endif #ifndef YY_EXIT_FAILURE #define YY_EXIT_FAILURE 2 #endif #ifdef YY_USE_PROTOS static void yy_fatal_error( yyconst char msg[] ) #else static void yy_fatal_error( msg ) char msg[]; #endif { (void) fprintf( stderr, "%s\n", msg ); exit( YY_EXIT_FAILURE ); } /* Redefine yyless() so it works in section 3 code. */ #undef yyless #define yyless(n) \ do \ { \ /* Undo effects of setting up yytext. */ \ yytext[yyleng] = yy_hold_char; \ yy_c_buf_p = yytext + n - YY_MORE_ADJ; \ yy_hold_char = *yy_c_buf_p; \ *yy_c_buf_p = '\0'; \ yyleng = n; \ } \ while ( 0 ) /* Internal utility routines. */ #ifndef yytext_ptr #ifdef YY_USE_PROTOS static void yy_flex_strncpy( char *s1, yyconst char *s2, int n ) #else static void yy_flex_strncpy( s1, s2, n ) char *s1; yyconst char *s2; int n; #endif { register int i; for ( i = 0; i < n; ++i ) s1[i] = s2[i]; } #endif #ifdef YY_USE_PROTOS static void *yy_flex_alloc( yy_size_t size ) #else static void *yy_flex_alloc( size ) yy_size_t size; #endif { return (void *) malloc( size ); } #ifdef YY_USE_PROTOS static void *yy_flex_realloc( void *ptr, yy_size_t size ) #else static void *yy_flex_realloc( ptr, size ) void *ptr; yy_size_t size; #endif { /* The cast to (char *) in the following accommodates both * implementations that use char* generic pointers, and those * that use void* generic pointers. It works with the latter * because both ANSI C and C++ allow castless assignment from * any pointer type to void*, and deal with argument conversions * as though doing an assignment. */ return (void *) realloc( (char *) ptr, size ); } #ifdef YY_USE_PROTOS static void yy_flex_free( void *ptr ) #else static void yy_flex_free( ptr ) void *ptr; #endif { free( ptr ); } #if YY_MAIN int main() { yylex(); return 0; } #endif #line 106 "test.1" /*该函数设置yyin变量，fflex对yyin变量所对应的文件进行词法分析*/ void BeginCompileOneFile( const char * filename ) { yyin = fopen( filename, "r"); fseek( yyin, 0, SEEK_SET ); } void EndCompileOneFile(void) { fclose(yyin); yyin = 0; } int yywrap()/*多文件*/ { return 1; } int exp() { return 1; } int installID() { return 1; } int installNum() { int tokenval=0; /*yytext*/ char *p=yytext; while(*p>='0'&&*p<='9') { tokenval=tokenval*10+*p-'0'; p++; } return tokenval ; } /* #ifdef __cplusplus extern "C" int yylex(void); extern "C" void BeginCompileOneFile( const char * filename ); extern "C" void EndCompileOneFile( void); #endif */ /*void main() { int token; char filename[1000]; printf("请输入要编译的源程序文件名："); gets(filename); BeginCompileOneFile( filename ); //当flex扫描到文件末尾，yylex函数返回0 while( ( token = yylex() ) > 0 ) ; EndCompileOneFile(); getchar(); } */
yytex.h
View Code
#define ID_TKN 500 #define NUM_TKN 510 #define RELOP_TKN 520 #define RELOP_AD 521 #define RELOP_SU 522 #define RELOP_MU 523 #define RELOP_DI 524 #define RELOP_LT 525 #define RELOP_LE 526 #define RELOP_EQ 527 #define RELOP_NE 528 #define RELOP_GT 529 #define RELOP_GE 530 #define RELOP_SENI 531 #define RELOP_COMMA 532 #define LEFT_BRACKET 530 #define RIGHT_BRACKET 531 #define LEFT_MIBRACKET 532 #define RIGHT_MIBRACKET 533 #define LEFT_BIBRACKET 534 #define RIGHT_BIBRACKET 535 #define IF_TKN 610 #define WHILE_TKN 611 #define DO_TKN 612 #define BREAK_TKN 613 #define REAL_TKN 614 #define TRUE_TKN 615 #define FALSE_TKN 616 #define BASIC_TKN 617 #define ELSE_TKN 618
a.txt
View Code
{ i = 2; while (i <=100) { sum = sum + i; i = i + 2; } }
main调用parse
parse调用yytex.cpp中的函数（又test1.l经flex的来）
a.txt为测试的程序代码。（用于测试自做的编译器）
