The file offers a few handy functions on standard C++ containers
(principally vector and list).
out << L output elements of L (as comma separated list in square brackets)
product(L) returns the product of the entries of L; gives error
if L is empty.
sum(L) returns the sum of the entries of L; gives error
if L is empty.
HasUniqueOwner(L) returns true if the entries of L all have the
same owner; gives error if L is empty.
LexCmp3(begin1,end1, begin2,end2) do a 3-way lex comparison; returns
<0,=0,>0 according as first seq is <,=,> second seq. Uses cmp between
elements, and assumes cmp returns <0,=0,>0.
The output functions are specifically only for vector and list;
I cannot make it more general without ambiguities arising.
The implementations of the printing functions could hardly be simpler.
The only "clever" part is the fn OutputRange which actually does the work.
Implemented as template code in the header file.
The implementation is slightly indirect to allow use of std::for_each
(also so that would work with lists/vectors/etc)
OutputRange is publicly visible, but is not intended for public use.
Impl of sum and product is a bit too complicated.
Need a template expert to clean it.
Perhaps add also a LexCmp3 that takes complete containers?
Currently it is "STL compatible" (which I think is usually awkward).
It would make the calls in symbol.C neater!
Activate the commented out template fn cmp?
The type int seemed the most natural choice for the return value of this
three-way comparison functions (though signed char would be big enough).
The implementation assumes that operator< is defined; this decision was
inspired by assumptions made by various STL functions. The types of the
arguments may be different as this is probably be more convenient for the
user. Obviously the generic definition given here can be overridden by
more efficient specific definitions for certain argument types.
2014