Strongly typed heterogeneous record types!

Some utility functions can be found in lenientTuple:

• target <~ source: copy all values from a tuple to another tuple or object
• t1 ==~ t2: check if two tuples are equal regardless of order
• to(src:tuple, T:type tuple): convert from a tuple type to another tuple type that differs only in key order
• =~: assign from one tuple to another with the same keys, possibly in a different order
• len,hasKey,[],[]=: operations that treat a tuple similar to a Table[static string, typed].

TupleOps has some utility methods to combine and reason about Tuples.

• tupleKeys(t): return the field names as strings @[k0, k1, ...]
• project(t, keys): project the tuple onto the selected keys. Returns a tuple with only the given keys.
• reject(t, keys): reject the given keys, returning a tuple with all keys from t not in keys
• concat(t1, t2) / &: given two tuples (positional or with non-overlapping keys), return a new tuple combining them. This will fail at compile time if the keys overlap.

Relations has an implementation of relational algebra on Nim named tuples. Viewing a relation as a seq[tuple], the following relational operators are defined:

• Projection = project(rows, ["someKey", ...])
• Selection = select(rows, predicate)
• Natural join = join(rows1, rows2)
• Rename = rename(rows, {"newKey1":"oldKey1", ...})