Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA
Path: utzoo!watmath!clyde!bonnie!akgua!mcnc!decvax!genrad!panda!talcott!harvard!seismo!brl-tgr!tgr!ihnp4!inuxc!pur-ee!CS-Mordred!Pucc-HPucc-I: ags@ucb-vax.ARPA;
From: Pucc-HPucc-I:@CS-Mordred.UUCP
Newsgroups: net.micro
Subject: Turbo PASCAL quirk?
Message-ID: <8541@brl-tgr.ARPA>
Date: Sat, 23-Feb-85 13:30:41 EST
Article-I.D.: brl-tgr.8541
Posted: Sat Feb 23 13:30:41 1985
Date-Received: Wed, 27-Feb-85 05:47:56 EST
Sender: news@brl-tgr.ARPA
Lines: 44

>  What happens is that the line Sym_List := Nxt_Ident has no effect since
>  the With statement seems to lock you into the VALUE of the Sym_List 
>  pointer when you enter the With statement. Is this standard PASCAL?
>  I assumed, obviously incorrectly, that this code is equivalent to the
>  same code without the With and with all of the record fields prefixed 
>  with Sym_List^. 

The implementation is correct.  According to the American Pascal Standard,

	The record-variable shall be accessed before the statement
	of the with-statement is executed, and that access shall
	establish a reference to the variable during the entire
	execution of the statement of the with-statement.

The line Sym_List := Nxt_Ident does indeed have an effect (it changes
the value of Sym_List), but it does not affect the record-variable
access which is effective for the entire duration of the with-statement.

By the way, underscores in identifiers are not standard Pascal.

>  Type 
>    Ident_Ptr = ^Ident;
>    Ident = Record
>              Name       : String[127];
>              ID_Type    : Ident_Type;
>              References : Line_Ref;
>              Nxt_Ident  : Ident_Ptr;
>            End;
>  Var
>    Sym_List : Ident_Ptr;
>  
>  ...
>  
>    With Sym_List^ Do
>    Begin
>      While Name <> '' do
>      Begin
>        Writeln(Name);
>        Print_References(References);
>        Sym_List := Nxt_Ident;
>      End; (* While *)
>    End; (* With *) 
-- 
Dave Seaman			 ..!pur-ee!pucc-i:ags