Jos van Uden:
It depends on how you interpret it. The task describes two
actions:
display and append. The question is: does the last sentence
refer to
the append action or to both display and append. I choose to
think it
refers to the append action because that makes more sense.
OK.
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As for http://rosettacode.org/wiki/Simple_database
You removed the struct that I used to encapsulate the functions.
Aren't these functions now exposed to other modules? I wanted
them to only be callable from main. The input validation relies
on that.
At first I had declared them all private, but then I thought it
would be convenient to put a struct around them and declare it
private. Maybe there's a better way.
D isn't a pure OOP language, it thankfully supports free
functions. Generally structs and classes shouldn't be used if
they are not useful (this is well known in the Python community).
A struct with just static methods is essentially a namespace. In
D modules are namespaces, so there is less need to wrap static
functions in a struct.
In this case of the Simple database Task I think this is not a
module to be imported, because it has a main. It's a complete
program (like other hundreds of D Tasks in Rosettacode) and it's
not meant to be imported. So I think wrapping everything in a
struct in this case is useless, it just increases the indenting.
Do you agree?
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Extra note: in Rosettacode there are also few tasks meant as
modules to be imported and used. They have the main wrapped like
this:
version (task_name_main) {
void main() {
}
}
Unfortunately in D there is no built-in way to make a module that
has a main() when it's compiled as "main module" (or when it's
compiled as stand alone) and masks its main() when it's imported
by another module. This is done in Python with the "if __name__
== __main__:" idiom. Some people say that a similar idiom is
ugly, but it's far better to have such not nice looking but
standard idiom, than having nothing and using a nonstandard
version() like that.
Bye,
bearophile
