A practical lambda-calculator is a normal-order evaluator for the untyped lambda-calculus, extended with convenient commands and shortcuts to make programming in it more productive. Shortcuts are distinguished constants that represent terms. Commands define new shortcuts, activate tracing of all reductions, compare terms modulo alpha-conversion, print all defined shortcuts and evaluation flags, etc. Terms to evaluate and commands are entered at a read-eval-print-loop (REPL) "prompt" or "included" from a file by a special command. A Haskell branch is an embedding of the lambda calculator (as a domain-specific language) into Haskell. The calculator can be used interactively within Hugs or GHCi.
ACFTools is a utility for manipulating X-Plane flight simulator aircraft and weapon models without using its Plane Maker. It can decode both Apple and Intel ACF/WPN formats into plain text files with a syntax similar to C, which can be edited and then re-converted into binary data. It is able to extract almost complete 3D models of aircraft (fuselage, floats, tanks, wings, stabs, propellers, engines) and write it in AC3D modeler format. Edited 3D parts can then be merged into plain text and consequently converted into binary ACF files.