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大小: 1.22MB文件类型: .rar金币: 1下载: 0 次发布日期: 2023-10-15
- 语言: 其他
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资源简介
一个小小的词法分析器设计,文档有步骤使用说明和基础语法讲解,还有实现效果截图,是事先写好好词法分析器的规则,再利用Flex工具自动生成.c文件,再利用编译器生成可执行文件即可
代码片段和文件信息
/* A lexical scanner generated by flex */
/* Scanner skeleton version:
* $Header: /home/daffy/u0/vern/flex/RCS/flex.sklv 2.91 96/09/10 16:58:48 vern Exp $
*/
#define FLEX_SCANNER
#define YY_FLEX_MAJOR_VERSION 2
#define YY_FLEX_MINOR_VERSION 5
#include
/* cfront 1.2 defines “c_plusplus“ instead of “__cplusplus“ */
#ifdef c_plusplus
#ifndef __cplusplus
#define __cplusplus
#endif
#endif
#ifdef __cplusplus
#include
#include
/* 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
#include
#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. */
#defin
属性 大小 日期 时间 名称
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文件 1226215 2017-06-22 11:34 利用FLEX设计一个small c的词法分析器\flex-2.5.4a-1.exe
文件 43435 2017-06-23 03:39 利用FLEX设计一个small c的词法分析器\lex.yy.c
文件 77856 2018-01-15 15:13 利用FLEX设计一个small c的词法分析器\利用FLEX设计一个small c的词法分析器.docx
文件 116 2017-06-23 04:22 利用FLEX设计一个small c的词法分析器\src.txt
文件 1851 2017-06-23 04:53 利用FLEX设计一个small c的词法分析器\lex.l
目录 0 2018-01-15 15:06 利用FLEX设计一个small c的词法分析器
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