I was hacking around with trying to use templates to combine inline iterators,
and I wasn't successful, but I'm not sure what the problem is.
template chain(iter1, iter2: typed): typed =
iterator res: string {.inline.} =
for r1 in iter1():
yield r1
for r2 in iter2():
yield r2
res
iterator thing1: string =
yield "A"
yield "B"
yield "C"
yield "D"
iterator thing2: string =
yield "E"
yield "F"
yield "cookiemonster"
for thing in chain(thing1,thing2):
echo(thing)
The error is "value of type 'iterator (): string{.inline, noSideEffect, gcsafe,
locks: 0.}' has to be discarded; for a function call use ()"
It's pretty easy to make something like this work:
chain(dummyname,thing1,thing2)
for thing in dummyname:
...
But I can't quite get the template to produce something that goes in the for
statement itself.
* * *
The other problem is the iterators might not always yield a string, but it
eludes me how to declare my wrapper iterator to return type(elementof(thing1))
