• Arcane Jill (20/20) Aug 23 2004 The following compiles, links and runs without complaint. The output is ...
• Arcane Jill (6/29) Aug 25 2004 Erk. I seem to have written "callee" when I meant "caller".
• Walter (6/26) Aug 25 2004 I've fixed it so the compiler generates an error if you have an in witho...
• Arcane Jill (5/7) Aug 26 2004 But a closed-source library would /want/ to specify an in without a body...
• Walter (9/16) Aug 26 2004 without a

Arcane Jill <Arcane_member pathlink.com> writes:

The following compiles, links and runs without complaint. The output is -nan.
This is wrong.

What I would have /expected/ is that the program would compile, but not link,
since the function body of squareRoot() has not been supplied.

This is exactly the sort of thing you want to put in a "header file".
















This also reinforces my point that preconditions need to be checked by the
callee (unlike postconditions).

Jill

Arcane Jill <Arcane_member pathlink.com> writes:

Erk. I seem to have written "callee" when I meant "caller".
caller = the code which calls a function
callee = the code inside the function body.
Sorry.

So of course, I should have said:
This also reinforces my point that preconditions need to be checked by the
caller (unlike postconditions).
    ^^



In article <cgcjqc$2ag5$1 digitaldaemon.com>, Arcane Jill says...
The following compiles, links and runs without complaint. The output is -nan.
This is wrong.

What I would have /expected/ is that the program would compile, but not link,
since the function body of squareRoot() has not been supplied.

This is exactly the sort of thing you want to put in a "header file".
















This also reinforces my point that preconditions need to be checked by the
callee^Hr (unlike postconditions).

Jill

"Walter" <newshound digitalmars.com> writes:

I've fixed it so the compiler generates an error if you have an in without a
body.

"Arcane Jill" <Arcane_member pathlink.com> wrote in message
news:cgcjqc$2ag5$1 digitaldaemon.com...
 The following compiles, links and runs without complaint. The output

is -nan.
 This is wrong.

 What I would have /expected/ is that the program would compile, but not

link,
 since the function body of squareRoot() has not been supplied.

 This is exactly the sort of thing you want to put in a "header file".
















 This also reinforces my point that preconditions need to be checked by the
 callee (unlike postconditions).

 Jill

Arcane Jill <Arcane_member pathlink.com> writes:

In article <cgiphe$2ev0$3 digitaldaemon.com>, Walter says...
I've fixed it so the compiler generates an error if you have an in without a
body.

But a closed-source library would /want/ to specify an in without a body. You
need to be able to expose the precondition to the caller without the
implementation.

Arcane Jill

"Walter" <newshound digitalmars.com> writes:

"Arcane Jill" <Arcane_member pathlink.com> wrote in message
news:cgk49c$213$1 digitaldaemon.com...
 In article <cgiphe$2ev0$3 digitaldaemon.com>, Walter says...
I've fixed it so the compiler generates an error if you have an in


without a
body.

 But a closed-source library would /want/ to specify an in without a body.

You
 need to be able to expose the precondition to the caller without the
 implementation.

This would imply that the caller must execute the precondition rather than
the callee. This is problematical in the case of polymorphic preconditions.

It may be possible to solve that problem, but if so, it would be a post 1.0
feature. For 1.0, preconditions are part of the callee implementation, and
so must have a body to go with them.