ContinuumIO/blaze — pull request #377 by mattwescott (2014-07-11 18:49:15+00:00)
Title: Fix repr when Table is backed by mutable data

The data backing a table was being hashed while computing head. This resulted in TypeErrors when viewing Tables backed by DataFrames.

Fixing this required changes in three places:

1. The hash of a table is now the hash of the schema, the name and the id of the backing data.
* This change could lead to unexpected behavior when there are multiple tables backed by equal but not identical data.
2. Traversing a TableExpr now doesn't touch the data backing any of the tables in the expression.
3. There is now an into function for DataFrame -> DataFrame