Re: READLN not reading

Profetas wrote:
> 
> I have a simple menu program that loops and ask the user to type a
command,
> 
> but after the first command is typed the readln
> doesn't read it properly
> 
> That doesn't affect much, but it is driving me mad.
> 
> has anybode had the same problem?
> 
> I am using freepascal BTW.
> 
> Thanks (the code is below)
> 
> PROGRAM LexDemo;
> 
> USES Scanner,Parser;
> 
> {VAR}
> 
> { PRE   TRUE }
> { POST  Menu printed out }
> PROCEDURE Menu();
> 
> BEGIN
>   WRITELN('  Logical calculator      by Lucas S Silvs ');
>   WRITELN('+------------------------------------------+');
>   WRITELN('+           Main Menu                      +');
>   WRITELN('+------------------------------------------+');
>   WRITELN('| D -=> Display menu                       |');
>   WRITELN('| L -=> Lex keyboard input                 |');
>   WRITELN('| P -=> Parser the tokens into parse tree  |');
>   WRITELN('| E -=> Ealuate the parser tree            |');
>   WRITELN('| B -=> Bind an identifier to a value      |');
>   WRITELN('| S -=> Show the values of all identifiers |');
>   WRITELN('| Q -=> Quit                               |');
>   WRITELN('| Print (m)enu                             |');
>   WRITELN('| (l)ex token from standard input          |');
>   WRITELN('| lex token(s) from standard input         |');
>   WRITELN('| (r)ead string                            |');
>   WRITELN('| lex tokens from s(t)ring                 |');
>   WRITELN('+------------------------------------------+');
> END {Menu};
> 
> PROCEDURE Main_Loop();
> VAR
>         Option : CHAR;
> 
> BEGIN
>         Option := 'd';
>    WHILE Option <> 'q' DO
>        BEGIN
>             CASE Option OF
>                'L' : yylex();
>                'P' : yyparser(Tokens);
>                'l' : Menu();
>                's' : Menu();
>                'r' : Menu();
>                'd' : Menu();
>               ELSE
>                   Menu();
>               END;
> 
>        WRITE('Type your command: ==> ');
>       READLN(Option);
>  END
> END {Main_Loop};
> 
> BEGIN
>    Main_Loop();
> END. {LexDemo}

How do you enter your first command? Do you type say an 's' and wait
for something to happen or do you type 's'+<Enter>?

Hanford