[Info-vax] Programming languages on VMS

[Arne Vajhøj]

On 2/1/2018 5:40 PM, seasoned_geek wrote:
> On Wednesday, January 31, 2018 at 9:20:50 PM UTC-6, Arne Vajhøj wrote:
>>>     the data can be in a file of massive size. Those other sort verbs require it to be in RAM.
>>> With COBOL SORT you can even sort on values which do not natively exist on the input file.
>>
>> There are libraries for sorting large disk files for other languages.
>>
>> But having it coming with the compiler is a benefit.
>>
> 
> I have never seen any of those libraries which allow you to sort a file on values not contained within it.

It is very common for sorting in both in-memory-structures and
on-disk-files to allow sending over comparison functions, comparator
objects, comparison lambdas (depends of paradigm of language used)
that can so whatever is needed for the comparison.

The wikipedia article about external sorting has links to a few
libraries. Including some that has the custom comparator.

A general C++ library STXXL - see:

http://stxxl.org/tags/1.4.1/tutorial_sorter.html


A Java library ExternalSorting - see:

http://static.javadoc.io/com.google.code.externalsortinginjava/externalsortinginjava/0.2.4/com/google/code/externalsorting/ExternalSort.html#mergeSortedFiles-java.util.List-java.io.File-java.util.Comparator-

Another example that may be familiar to some is the
VMS utility function SOR$BEGIN_SORT 5th argument.

[Note that per documentation that argument is ignored for
the high performance version]

Arne