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Date: Thu, 25 May 2006 07:33:06 -0700
From: glen herrmannsfeldt <gah@ugcs.caltech.edu>
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Newsgroups: comp.lang.ada,comp.lang.fortran
Subject: Re: Ada vs Fortran for scientific applications
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Date: 2006-05-25T07:33:06-07:00
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Dan Nagle wrote:

(snip)

> What's the difference between a programmer controlling a check,
> and a programmer setting a compiler option?

PL/I allows bounds checking to be turned on or off statement by 
statement or procedure by procedure, if desired.

Discussions of Java/JVM, which requires subscript checking, mention
that some may be able to move tests outside a loop, or even omit them 
all together when it can be determined at compile time (or JIT time) 
that a problem can't occur.  For example, a loop over the length of an 
array can't go out of bounds (unless the array is redefined).

If the compiler didn't detect it, but the programmer knew some loops 
couldn't exceed array bounds, it could be turned off for those statements.

-- glen