何使用Delphi中的TParser语法分析器类

何使用Delphi中的TParser语法分析器类
如何进行词法分析？
Newsgroups: comp.lang.pascal.delphi.misc
Subject: Re: How do I use Tparser?
From: jbui@scd.hp.com (Joseph Bui)
Date: 31 Jul 1995 22:15:29 GMT
To do what you want with Tparser, do:
procedure ParseFile(const AFileName: string);
var FS: TFileStream; AP: Tparser;
begin
FS:=TFileStream.Create(AFileName, fmOpenRead);
AP:=Tparser.Create(FS);
with AP do
repeat
case Token of
#1 : {Token is a pascal identifier}
{retreive with TokenString}
#2 : {Token is a pascal string ie. 'blah' or #<number>}
{retreive with TokenString}
#3 : {Token is a pascal integer in decimal or hex}
{Retreive with TokenInt}
#4 : {Token is a pascal floating point}
{retreive with TokenFloat}
else
{Token is a single character token, such as a comma}
{retreive with Token or TokenString}
until NextToken = #0; {#0 mean End Of File}
AP.Free;
FS.Free;
end;
The TokenInt and TokenFloat routines cause errors when you try
and use them on non-compatible tokens. Also, the detection of
integers/floats is flawed, so ".e" comes back as a floating
point, and "$$$$$" comes back as an integer (a hex number).
You can't go backwards, and if some sort of error occurs, you are
pretty much screwed. Thus I suggest you find and use my
objects. If you can't find them, email me, and I'll send you
a copy.