[Oberon] Re (2): LONGINT, RETURN & etc.

[eas lab]

Boys !
We are going back to the 1960's.
Structured programming was fully discussed/analysed then ......
all about GOTOs ....

OTOH "is more understandable" is most important, but apparently very subjective.
I must continually ask myself why nobody uses ETHO's superb TUI-interface,
and even less wily [under Linux] copied from ETHO [apparently copied
from PARC ?].


On 6/17/17, Chris Burrows <chris at cfbsoftware.com> wrote:
>> -----Original Message-----
>> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
>> peter at easthope.ca
>> Sent: Sunday, 18 June 2017 1:02 AM
>> To: oberon at lists.inf.ethz.ch
>> Subject: [Oberon] Re (2): LONGINT, RETURN & etc.
>>
>> From:	Chris Burrows <chris at cfbsoftware.com>
>> Date:	Sat, 17 Jun 2017 13:55:16 +0930
>> > http://www.astrobe.com/OberonSyntax/html/OberonSyntax.htm
>>
>> Date:	Sat, 17 Jun 2017 13:40:15 +0930
>> > What you can't have is just RETURN without an expression.
>>
>> According to your diagrams an expression can be factor and a factor
>> can be NIL or " ". So "RETURN END" is OK.  Interesting edge case!
>>
>
> No.
>
> NIL is a reserved word representing a null POINTER, " " is a blank CHAR.
> They do not denote that 'expression' is optional.
>
>   RETURN NIL END is valid
>
>   RETURN " " END is valid
>
>   RETURN END is not valid
>
> If expressions were optional then statements like
>
>   IF THEN DoSomething END;
>
>   FOR i := TO BY DO DoSomething END;
>
> would also be syntactically correct!
>
> Regards,
> Chris Burrows
> CFB Software
> http://www.astrobe.com
>
>
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