…ange because the result included in the primop argument)

…rded...)

…opied to the store.

Well, they're still not inverse because a path gets converted to a string, but that doesn't seem
to be a problem so far

…ayed

currently only supported for nix-instantiate (and thus probably also nix-build), not yet nix-env
add --playback option to play back the exact command

So the interface is now:
"NIX_RECORDING=filename nix-instantiate ..." to record the nix-instantiate command
and
"nix-instantiate --replay filename" to play it back

commands in file

fix json encoding

In combination with nix channels (or the newer http download), the whole channel is treated as one input

we write 3 files to the nix closure:
-> default.nix: just imports the other two and can be imported to get the exact reproducable output we want to have
-> nix-support/recording.nix: recordings of all impurities i. e. function calls and imported files
-> nix-support/expressions.nix: the expression that will be executed

for the expression, a primop __findAlongAttrPath that does the supplies
the autobindings along the attrpath.

for the playback, a new primop prim_playback has been introduced. It's first parameter
is a description of all impurities (as written to expression.nix).
After this function is invoked, all subsequent calls can use the functions introduced here.

In general, we allow multiple prim_playback when they don't conflict (not in all cases conflicts are found yet)

It would also be cool to make the prim_playback more local, e. g. it should only apply
to a specific term, but it's unclear to me how this can be achieved in a lazy language.

…k to recorded source closure (not registered in garbage collection)