TODO

Errors:

warning messages from top-level task callback '1'
Warning messages:
1: In svg(path) :
  unable to load shared object '/Library/Frameworks/R.framework/Resources/library/grDevices/libs//cairo.so':
  dlopen(/Library/Frameworks/R.framework/Resources/library/grDevices/libs//cairo.so, 6): Library not loaded: /opt/X11/lib/libcairo.2.dylib
  Referenced from: /Library/Frameworks/R.framework/Resources/library/grDevices/libs//cairo.so
  Reason: Incompatible library version: cairo.so requires version 11403.0.0 or later, but libcairo.2.dylib provides version 11203.0.0
2: In svg(path) : failed to load cairo DLL
3: In file(con, "rb") :
  cannot open file '/var/folders/rb/db6l8q955dsd61tzb__3b_cc0000gn/T//Rtmpm1Ld1y/file1fd6658f6f08.svg': No such file or directory
4: could not create a commit: cannot open the connection 

po tracking_off() próbuję zrobić ponownie tracking_on():
> tracking_on()
using an existing object store: "/Users/pchudzia/workspace/project-store"
Error: global environment is not empty, cannot restore commit, aborting


* General:
  - make the session env a part of the state object
  - add a `commit_id` argument to `tracking_on`; create a `tracking_on_`
    programmatic (non-interactive) API

* Widget:
  - use RStudio addins to browse history with keyboard (up/down),
    similarly to Ctrl+R in regular R console

* tracking:
  - examine the .Last.value - in case there was no object
  - ignore plots present on the device upon turning tracking on
  - wait for failed commands and if one arrives, check if the user entered
    a valid commit/object id, and if so, restore it

* explain: find a full sequence of calls leading to a given object

* UI:
  - show history of commits
  - print commits
  - show history of expressions in the current branch
  - list branches
  - name branches
  - clean the stash

* move plot.result to compare - plot.result should show something
  similar to plot.graph - a graph of inter-related objects