Expression syntax in programming languages.

[00704a-Liber]

[followups to comp.misc]

In article <20520 at beta.lanl.gov> jlg at beta.lanl.gov (Jim Giles) writes:
>In article <5174 at ihlpf.ATT.COM>, nevin1 at ihlpf.ATT.COM (00704a-Liber) writes:
>> Since when does 'x = x + 1' resemble anything besides an obviously false
>> statement in mathematics??  Also, since many of us use C for tasks other
>> than number crunching, does this mean that we should have NO desire for a
>> programming language to resemble mathematics?  Your reasoning is a little
>> faulty here.

>But not as faulty as yours.  I maintain that the expression syntax
>should be kept as close as possible to accepted mathematical conventions.
>You seem to be maintaining that, because exact duplication is not possible,
>the language designer shouldn't even try to be similar.

If you are designing a language specifically for mathematics, then using an
expression syntax consistent with mathematical conventions might be
desired.  However, most of what computers are used for is not for number
crunching.  What makes mathematical convention better than any other
convention??

Another thing:  people tend to think of the '+' operator (with respect to
some computer languages) as being the same as the one commonly found in
mathematics.  These operators do not exhibit the same properties, however
(in finite floating point arithmetic, addition is NOT associative.  I wish
I could remember who originally posted this fact).

>If you would
>read my entire statement (in which I said that both C _and_ Fortran were
>far from perfect), you wouldn't be accusing me of claiming that assignment
>is a mathematical syntax.

Very little of what computers do correlates directly to mathematics.
Mathematics is a declarative language, but computer languages are
algorithmic.

>> A function call may not necessarily be made (can you say 'inlining').

>I can not only SAY it, I can also notice that C doesn't do it (as I've
>pointed out before).  The C language definition (such as it is) doesn't
>allow it.

It has always been allowed (this is an implementation detail, not a language
detail).

>If the presence of an exponentiation operator can be considered as an
>'error' in Fortran, then an inherently inefficient part of C can be
>considered 'broken'.

Who said that the exponentiation operator is an error in FORTRAN?  But just
because FORTRAN has it, that is no reason to believe that every other computer
language should have it.  If it doesn't fit in well with the language
paradigm, then it shouldn't be kludged in.

The inefficiency is due to implementation details; it is not inherent in
the language.
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