Re: Ada standard and maximum line lengths

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 13-01-29 13:31 , Georg Bauhaus wrote:
> On 29.01.13 11:25, Niklas Holsti wrote:
>> 200 characters is ok as a max line
>> length. 200 for an identifier is overkill, IMO.
> 
> When the meaning of "meaning" is defined by a programming
> environment, naming capabilities may need to tackle names that the
> environment imposes on the source. The names may exist for, and be
> shaped by, hysterical raisins. For example, the following is listed
> as a symbol from the text section of a standard C++ library:
> 
> __ZNSt3__112basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEE6insertIPKwEENS_9enable_ifIXsrNS_21__is_forward_iteratorIT_EE5valueENS_11__wrap_iterIPwEEE4typeENSD_IS8_EESB_SB_

As you well know, that is a compiler-generated mangled "symbol", not a
user-written identifier. Its extreme length is an artefact of the
historical limitations on linkers and the linking process, in particular
the lack of name-space control and of overloaded symbols (resolved by
type or profile) and the requirement for separate compilation of modules
without any central compilation/information library. This forces the C++
compiler to encode many properties of the C++ object, named by some much
shorter source-code identifier, into the symbol used for linking.

Even for hypothetical SW of some sort that generates Ada source code
automatically, I think it very unlikely that it would generate
identifiers of that length, since Ada identifiers can be qualified and
sorted into packages etc. much more flexibly than is the case for linker
symbols.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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