tonsky/datascript — pull request #21 by montyxcantsin (2014-08-31 21:46:40+00:00)
Title: adding support for get-else as built-in pred

Not sure if this is the best approach as it required passing along `context` to `-call-fn` in both `filter-by-pred` and `bind-by-fn` to allow resolving `$` to a source. This will also be necessary for `get-some`, `missing?` and similar though so I am going to run with it for now.