On Sunday, 2 March 2014 at 18:59:23 UTC, Steve Teale wrote:
On Sunday, 2 March 2014 at 15:23:03 UTC, H. S. Teoh wrote:
This is a pretty good primer to templates:
https://semitwist.com/articles/article/view/template-primer-in-d
The trouble is with most of these tutorials that they offer
examples that are things you would probably never want to do. I
can already add an int to an int, or a double to a double, or
an int to a double.
Perhaps the examples should pick on something like vector
operations, but then who would be doing those with int, or some
class? It would be doubles or pairs of, as in struct Coord.
I believe readers would study documentation and examples much
more carefully if they were things they might realistically
want to do. And that won't be type conversion - std.conv
already does a pretty good job on that. So what?
We could really do with a place where template savvy open
source contributors could publish interesting examples of
template use.
Otherwise, Joe Soap, like me, can spend a great deal of time
and effort in:
a) Determining when the use of a template might be advantageous,
b) Hacking at test programs to determine what the documentation
means, and what works, and what doesn't.
c) After that, deciding whether it would be just as effective
to use two or three separate methods.
Steve
Steve
I'm always willing to use templates, but maybe in fact the use
cases are limited. I have a class for html elements (that
implements DOM functionality), and a class for building trees
with the tags. Of course, for html tags only string as a type
makes sense.
class Element(T) {
}
or
class HTMLElement(T) if (is (T == string)) {
}
Tree(T) {
}
I implemented it as a template, because I thought it might be
useful for other types as well, if I want to build a hierarchical
tree of extracted data, be it integers, floating point numbers or
whatever at a later point. However, I don't know a) if this will
ever be the case and b) if I won't have to modify the template to
adapt to new data types (which kinda defeats the purpose). I'm
not against templates, I'm just not sure, if there are so many
general or generalizable cases in programming for which templates
are _the_ solution.
