(reload module) doesn't reload Hy modules

[ghost]

No description provided.

[Kodiologist]

A simple way to reproduce this (on Python 3) is:

$ echo '(print "LOADED")' > test.hy
$ hy
hy 0.12.1+101.g5bf9ecf using CPython(default) 3.6.1 on Linux
=> (import test)
LOADED
=> (import importlib)
=> (importlib.reload test)
<module 'test' (<hy.importer.MetaLoader object at 0x7f1b0e9badd8>)>

"LOADED" should appear twice, but only appears once.

[asimjalis]

Here is a solution in Hy for reloading a file using its path. Useful for reloading from the REPL.

(defn slurp [path] (with [f (open path)] (.read  f)))
(defn hy-wrap-with-do [s] (+ "(do\n" s "\n)\n"))
(defmacro hy-load [path] `(->> ~path (slurp) (hy-wrap-with-do) (read-str) (eval)))

To reload the file "dir/script.hy" use (hy-load "dir/script.hy") on the REPL.

The reason for wrapping with (do ...) is that read-str only reads a single expr.

The reason for using defmacro instead of defn is that a defn limits the scope of the eval to its function—the definitions loaded from the script file are lost when we exit this function. Using defmacro loads the definitions into the global namespace.

[minghu6]

I find It's hard to limit the scope, inner function can limit it, but can't works with eval.

we may need let or let with limit its scope.

[Kodiologist]

Shouldn't this issue stay open? The bug remains in Hy master.

[vodik]

The right solution to this, if we want to put a reload in, is to remove the module from sys.modules and then import the module again.

This is what IPython's reloader does - but the reason it doesn't work with Hy is that the reloaded explicitly checks if __file__ ends with ".py". Patching that, it works

Now there are a lot of issues with how Hy manipulates sys.modules, and they're addressed with #1518. I really need to get that done, but the patch works. Its a matter of unit test coverage and documentation that's holding it back.

Soon! I promise. My free time is at a premium at the moment for personal reasons, but I want to make it a priority.