Roll your own IO

Given the existence of Golang interop and of reference variables, it is possible to write your own get and post statements to interact with whatever any Golang library can interact with.

In fact, most of Charm's IO is presently implemented that way, in a library called rsc/charm/world.go which is automatically imported with every Charm script. So for example to find out if a file exists, we import the Go os library ...

import

gocode "os"

... and we write a tiny Charm function ...

get (x ref) from (fileAccess FileExists) :
    x = goFileExists(fileAccess[filepath])

... which wraps around an almost equally tiny Go function:

goFileExists(fname string) : gocode {
    _, err := os.Stat(fname)
    return err == nil
}

And that's all there is to it.