Link to documentation, install notes, preview of functionality

README.md

@@ -1,5 +1,24 @@
 A random assortment of *things* that don't really demand their own package.
 
+## Use
+
+To use, include in the dependencies section of ``Cargo.toml``:
+
+    grabbag = "0.1.*"
+
+An overview of functionality is available [in the documentation](https://danielkeep.github.io/rust-grabbag/doc/grabbag/).
+
+For example:
+
+* ``collect!`` provides a way to initialise any container for which there is a FromIterator implementation, similar in use to ``vec!``.
+* ``sequence!`` creates an iterator over a fixed sequence, such as ``sequence![ n: u64 = 2*(n as u64) + 1 ]`` for positive odd integers.
+* ``group_by`` splits an iterator into a iterator of iterators, with elements grouped by a criterion.
+* ``cartesian_product`` combines every item in the first iterator with every item in the second iterator, e.g. ``(1, 2, 3) x (4, 5) = ((1, 4), (1, 5), (2, 4), (2, 5), (3, 4), (3, 5))``.
+* ``stride`` yields every ``n``th element, ``take_exactly`` takes ``n`` items, ``skip_exactly`` skips ``n`` items.
+* ``intersperse`` it like join, inserting an element inbetween every two items.
+
+And various other helpers [in the documentation](https://danielkeep.github.io/rust-grabbag/doc/grabbag/index.html).
+
 ## License
 
 Licensed under either of