wordpro.l

这是一个和lex功能差不多的parser编写的程序

%{
{*
 * 基于符号列表定制的单词识别
 *}

program WordPro;

{$APPTYPE CONSOLE}

uses
  SysUtils, LexLib, Classes;

type 
  TWordState=(wsLookUp, wsVerb, wsAdj, wsAdv, wsNoun, wsPrep, wsPron, wsConj);
  TWord=class(TObject)
  public
    word:string;
    State:TWordState;
  end;

var
  state:TWordState; 
  WordList:TStringList;

function LookUpWord(word:string):TWordState;
var
  I:integer;
begin
  I:=WordList.IndexOf(Word);
  if I>-1 then
  begin
    result:=TWord(WordList.Objects[I]).State;
  end
  else
    result:=wsLookUp;
end;

function AddWord(State:TWordState; Word:string):integer;
var
  WordObj:TWord;
begin
  //struct word *wp;	
  if (LookUpWord(Word)<>wsLookUp) then
  begin
    Writeln(format('!!! %s 已经被定义了', [word]));
    result:=0;
    exit;
  end;
	
  WordObj:= TWord.Create;
  WordObj.Word:=Word;
  WordObj.State:=State;
  WordList.AddObject(Word, WordObj);
  result:=1;
end;

%}
%%
\n	state := wsLookUp;

^verb	state := wsVerb;
^adj	state := wsAdj;
^adv	state := wsAdv;
^noun	state := wsNoun;
^prep	state := wsPrep;
^pron	state := wsPron;
^conj	state := wsConj;

[a-zA-Z]+  begin
	     if(state <> wsLookUp) then 
	     	AddWord(state, yytext)
	     else
	     begin
		Case LookUpWord(yytext) of
 		  wsVerb: Writeln(format('%s 是动词', [yytext]));
		  wsAdj: Writeln(format('%s 是形容词', [yytext]));
		  wsAdv: Writeln(format('%s 是副词', [yytext]));
		  wsNoun: Writeln(format('%s 是名词', [yytext]));
		  wsPrep: Writeln(format('%s 是介词', [yytext]));
		  wsPron: Writeln(format('%s 是代词', [yytext]));
		  wsConj: Writeln(format('%s 是连词', [yytext]));
		  else
		     Writeln(format('%s 无法识别', [yytext]));
		end;
            end;
          end;

.	{* 忽略剩下的所有的字符串 *} ;

%%
begin
  WordList:=TStringList.Create;
  try
    yylex;
  finally
    //Todo:释放WordObj
    WordList.Free; 
  end;
end.