java语言的词法分析器（手动与flex）。使用cmake、c语言构建。.zip

# JAVA词法分析器 ## 切分TOKENS  原本是将常量这划分成了所有的类型，还特别标注了byte、boolean与String是要自己实现的 还想好了，用结构与联合实现存储不定长度内容的东西 突然想起来，这是词法分析 ## flex自动生成 简单展示分类 ```C /* 关键字定义 */ ABSTRACT abstract DEFAULT default GOTO goto NULL null SWITCH switch BOOLEAN boolean DO do IF if PACKAGE package NCHRONZED nchronzed BREAK break DOUBLE double IMPLEMENTS implements PRIVATE private THIS this BYTE byte ELSE else IMPORT import PROTECTED protected THROW throw THROWS throws CASE case EXTENDS extends INSTANCEOF instanceof PUBLIC public TRANSIENT transient CATCH catch INT int RETURN return CHAR char FINAL final INTERFACE interface SHORT short TRY try CLASS class FINALLY finally LONG long STATIC static VOID void CONST const FLOAT float NATIVE native STRICTFP strictfp VOLATILE volatile CONTINUE continue FOR for NEW new SUPER super WHILE while ASSERT assert ENUM enum /* 关键字定义结束 */ /* 运算符定义 */ QUES \? COLON [:] ASSIGNOP [=] RELOP [>]|[<]|[>][=]|[<][=]|[=][=]|[!][=] PLUS [+] SUB [-] MUL [*] DIV [/] AND [&][&] OR [|][|] /* 运算符定义结束 */ /* 分界符定义 */ ATT \@ DOT [.] COMMA [,] NOT [!] SEM [;] LP \( RP \) LB \[ RB \] LC \{ RC \} /* 分界符定义结束 */ /* 常数定义 */ STA_INT (-?[1-9][0-9]*|0) STA_FLOAT -?(0|[1-9]+)\.[0-9]* STA_CHAR \'[a-zA-Z]\' STA_STRING \".*\" STA_BOOLEAN (true|false) /* 常数定义结束 */ /* 标识符定义 */ ID [a-zA-Z_$][a-zA-Z_$]* /* 标识符定义结束 */ LINECOMMENT \/\/.* COMMENT ((\/\*((\*[^\/]+)|[^\*])+\*\/)|(\/\/)) %option noyywrap %% {ABSTRACT} | {DEFAULT} | {GOTO} | {NULL} | {SWITCH} | {BOOLEAN} | {DO} | {IF} | {PACKAGE} | {NCHRONZED} | {BREAK} | {DOUBLE} | {IMPLEMENTS} | {PRIVATE} | {THIS} | {BYTE} | {ELSE} | {IMPORT} | {PROTECTED} | {THROW} | {THROWS} | {CASE} | {EXTENDS} | {INSTANCEOF} | {PUBLIC} | {TRANSIENT} | {CATCH} | {INT} | {RETURN} | {CHAR} | {FINAL} | {INTERFACE} | {SHORT} | {TRY} | {CLASS} | {FINALLY} | {LONG} | {STATIC} | {VOID} | {CONST} | {FLOAT} | {NATIVE} | {STRICTFP} | {VOLATILE} | {CONTINUE} | {FOR} | {NEW} | {SUPER} | {WHILE} | {ASSERT} | {ENUM} { printf("< 关键字 , %10s >\n", yytext); } {QUES} | {COLON} | {ASSIGNOP} | {RELOP} | {PLUS} | {SUB} | {MUL} | {DIV} | {AND} | {OR} { printf("< 运算符 , %10s >\n", yytext); } {ATT} | {COMMA} | {DOT} | {NOT} | {SEM} | {LP} | {RP} | {LB} | {RB} | {LC} | {RC} { printf("< 分界符 , %10s >\n", yytext); } {STA_INT} | {STA_FLOAT} | {STA_CHAR} | {STA_STRING} | {STA_BOOLEAN} { printf("< 常数 , %10s >\n", yytext); } {ID} { printf("< 标识符 , %10s >\n", yytext); } {LINECOMMENT} | {COMMENT} | [ \n\t] //eat the white space ``` --- 注意yywrap()这个函数 具体可以参看[flex manual手册](https://westes.github.io/flex/manual/Generated-Scanner.html#Generated-Scanner) 有三种方法： 1. 在`definition`部分，添加如下内容 ``` %{ #define yywrap() 1 %}``` 2. 在`user code`部分，添加函数 ``` int yywrap(){ return 1; }``` 3. 在`definition`部分添加`%option noyywrap` --- ## 手动实现