[Info-vax] Variable declarations, was: Re: improving EDT
Arne Vajhøj
arne at vajhoej.dk
Sat Nov 19 21:53:19 EST 2016
On 11/19/2016 4:12 PM, Scott Dorsey wrote:
> Back in the 1960s there was a valid argument for automatic variable
> assignment, and back then there were compiler listings and everyone
> was warned to be very very careful to make sure that there weren't
> any spurious variables showing up on their listings.
>
> Today modern compilers and debugging practices that came into existence
> in the 1970s and 1980s make listings far less important and one of those
> things is forcing explicit declarations.
>
> If you're using a language that will automatically set up undeclared
> variables for you, it's just a matter of time before you accidentally
> typo that comma and write:
>
> DO 10 I=1.5
>
> which is an assignment statement and not a loop statement. And if you
> don't notice this new DO10I variable that shows up on your listing, you
> are going to be in for a world of hurt.
True.
But no modern language has the space not significant rule.
Arne
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