Leave channel construction and goroutining to callers

[larsmans]

Just an idea: what if Entries.Keys and friends would not return a channel, but take one as an argument? That allows the caller to set the buffering, so a cact-like tool can perform reading and writing of corpora in parallel. (Untested proof of concept attached.)

[danieldk]

I think that's indeed an improvement. Perhaps an even better solution would be pass a function to Keys et al. Then a caller could implement whatever behaviour it wishes. E.g. a closure could feed the values to a channel. But it would give the caller the option to use concurrency or not.

[danieldk]

A comparable example:

https://github.com/danieldk/golinear/blob/master/problem.go#L105

[pebbe]

It has to be an unbuffered channel, or Break won't work. And you don't need a buffered channel to process its output in parallel.