scanner.lex

来自「有关JDBC的使用一些编程实例,有关与数据库连接的代码」· LEX 代码 · 共 50 行

import java.util.*;
import java.lang.*;
import java_cup.runtime.*;

%%

%{
static scanner foo;
public static void init() {
  foo = new scanner(System.in);
}

public static token next_token() throws java.io.IOException {
  return foo.yylex();
}
%}

%class scanner
%type token
%eofval{
return (new token(sym.EOF));
%eofval}

NUMBER=[0-9]+

WHITE_SPACE_CHAR=[\n\ \t\b\012]

%%

<YYINITIAL> ";" { return new token (sym.SEMI); }

<YYINITIAL> "+" { return new token (sym.PLUS); }

<YYINITIAL> "-" { return new token (sym.MINUS); }

<YYINITIAL> "*" { return new token (sym.TIMES); }

<YYINITIAL> "/" { return new token (sym.DIVIDE); }

<YYINITIAL> "%" { return new token (sym.MOD); }

<YYINITIAL> "(" { return new token (sym.LPAREN); }

<YYINITIAL> ")" { return new token (sym.RPAREN); }

<YYINITIAL> {NUMBER} { return new int_token (sym.NUMBER, Integer.parseInt(yytext())); }

<YYINITIAL> {WHITE_SPACE_CHAR} { }