[ ] Core language support
-[ ] Reader macros
-[X] Hashmap type
-[ ] Arbitrary-precision arithmetic support in numeric tower
-[X] Guaranteed tail-call optimization
-[X] Atoms
-[X] Symbol/atom interning
-[ ] Exceptions and handling
-[ ] Use persistent data structures in place of native Vec
-[X] Wrapper interface for global value-like objects (e.g. `path` and such)
-[ ] Continuations
-[ ] Defined binary serialization format w/ fast native-code encoder
[ ] Standard library
-[ ] Basic functions
--[ ] Lists
--[ ] Numerics
--[ ] Strings and formatting
--[ ] Control flow and conditionals
-[ ] Streams and I/O (`io/*`)
--[ ] Colorized terminal output
--[ ] Termcap interface
--[X] Global stream abstraction
-[ ] Environment
--[X] Environment variables
---[ ] Integrate with reader
-[ ] Async (`async/*`)
--[ ] Deferred/future values
--[ ] Asynchronous tasks (integrate with job control system)
--[ ] Parallel `map`/`reduce`/`filter` functions
-[ ] Filesystem (`fs/*`)
--[ ] Stat queries
--[ ] Manipulation
--[ ] Globbing
[ ] Built-in commands
-[ ] Directory management (`cd`, `pwd`, `pushd`, `popd`, etc)
-[ ] Job management (`fg`, `bg`, `jobs`, `kill`)
[ ] Support `.yshrc` files
[ ] Pipeline adapters and endpoints
-[ ] Terminal elements
-[ ] Source elements
-[ ] Stream parsing support
-[ ] Pretty-printing output
-[X] Automatic symbol globbing in command transformers
[ ] Job control
-[ ] Backgrounding jobs (via `&` or some other means)
-[ ] Job control interface functions
-[ ] Reattaching backgrounded output streams
--[ ] Use ptrace to hijack launched command's I/O streams?
-[ ] Integrate with futures/async tasks
[ ] Line editing
-[ ] Vim bindings
-[ ] Readline bindings
-[ ] Expose line editor to user code
-[ ] Multi-line input based on reader results
--[ ] Better reader output type
-[ ] Extensible binding support
-[ ] Allow implementing editing disciplines in user code
-[ ] Completions
--[ ] Expose to user code
--[ ] Allow completion overrides from user code
[ ] History support
-[X] Store commands in history
-[X] Expose to user code
-[ ] Built-in support for recall and search
-[ ] Semantic history (store/expose as values, search by filter)
-[ ] Store previous command results
[ ] Debugging & Profiling
-[ ] User code debugger
-[ ] Memory profiling and optimization
-[ ] CPU usage profiling
[ ] Documentation
-[ ] HTML/PDF manual and tutorial
-[ ] Standard library reference
-[ ] Smart `man` command which can pull doc data out of the passed object
[ ] Quality-of-life Improvements
-[ ] Destructuring in `let`/`fn`
-[ ] `#()` shorthand for embedded pipelines (swap with current `$()` lambda?)
-[ ] Support lenses for easier filtering over streams