Olin Lathrop wrote:

> Gerhard Fiedler wrote:
>>> I'd rather write
>>>
>>>   strb <-- stra + stru + " more stuff"
>>>
>>> than
>>>
>>>   strb <-- StringConcatenate(stra, stru, " more stuff");
>> 
>> So do I, but I fail to understand why this requires that the string
>> handling is built into the compiler. 
>> 
>> Your preferred syntax looks (in principle) quite similar to the C++
>> std::string syntax, where normal string handling is implemented in a
>> standard library.
> 
> First, that only works when a language allows user defined operators
> like C++ does, but most other compiled languages don't.  

We're not talking here about specific features of specific languages,
but about what's exactly the difference of e.g. a string implementation
being built into the compiler or implemented in a standard library --
focus on /standard/ library (which means that the string behavior is in
both cases defined by the same language standard).

(In any case, allowing user-defined operators has a tremendous advantage
-- no matter whether the original operator is implemented by the
compiler or by a standard library. But this is somewhat besides the
point here.)

> Even then, the compiler only knows that some library routine has to be
> called to perform whatever the operation is.  It doesn't know it's
> string concatenation and therefore doesn't know as much about the
> intent of the statement as it would if it was built in.

Yes, it does. In C++, for example, the commonly used string
implementation is std::string. I can define my own std::string class
(using Pascal-style strings, for example), and the compiler can (and
should) assume that whatever is defined in the standard is true. If the
standard defines the operator '+' to be concatenation, this is what it
is -- built-in, compiler-vendor-supplied library, or custom
implementation.

The key here is "/standard/ library", as in "library with an interface
that's defined in the language standard, just like all the other
language elements".

Gerhard
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