Egison Pattern Source

The egison-pattern-src provides a standalone syntax definition for patterns in the Egison programming language. This package enables you to embed Egison's patterns in your parser (pretty-printer) by supplying expression and name parsers (printers) externally. For the uses in Haskell source code, such adaptors for haskell-src-exts and template-haskell are also available as egison-pattern-src-haskell-mode and egison-pattern-src-th-mode, respectively.

Syntax

The following is a simplified syntax of pattern expressions where v, c, op and e are meta-variables for variable names, constructor names, user-defined infix operators, and expressions in host language, respectively.

p ::= _                     (wildcard pattern)
    | $v                    (pattern variable)
    | #e                    (value pattern)
    | ?e                    (predicate pattern)
    | (p_1, p_2, ..., p_n)  (tuple pattern)
    | [p_1, p_2, ..., p_n]  (collection pattern)
    | p & p                 (and-pattern)
    | p | p                 (or-pattern)
    | !p                    (not-pattern)
    | p op p                (user-defined infix pattern)
    | c p_1 p_2 ... p_n     (constructor pattern)

Development

To build and test egison-pattern-src locally, run:

$ make test    # or just `cabal new-test all`

You can use make watch to watch for file changes and re-run tests.

License

egison-pattern-src is distributed as open source software under the terms of the 3 clause BSD License. See LICENSE for details.