The Functional XML Parsing Framework is a package of low-to-high-level lexing and parsing procedures that can be combined to yield a SAX, DOM, validating parsers, or a parser intended for a particular document type. The procedures in the package can be used separately to tokenize or parse various pieces of XML documents. The package supports XML namespaces, character, internal, and external parsed entities, xml:space, attribute value normalization, processing instructions and CDATA sections. It is intended to be a framework, a set of "Lego blocks" you can use to build a parser that follows DOM, SAX, or another discipline, and performs validation to any degree. As an example of such parser construction, the package includes a semi-validating SXML parser. It converts XML to SXML, an instance of XML Infoset as S-expressions, an abstract syntax tree of an XML document. SXML can be queried (in a XPath style), transformed, and evaluated. The framework parses XML in a pure functional style, as folding over a text XML document considered a spread-out tree. The input port is treated as a linear, read-once parameter. The framework's code does not use assignments at all.
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.