Package lepl :: Package matchers

Package matchers

Matchers form the basis of the library; they are used to define the grammar and do the work of parsing the input.

A matcher is like a parser combinator - it takes a stream, matches content in the stream, and returns a list of tokens and a new stream. However, matchers are also coroutines that can be "recalled" to return alternative matches. This gives backtracking.

Matchers are defined and implemented as both classes and functions. I have used the same syntax (capitalized names) for both to keep the API uniform.

For more background, please see the manual.

Submodules

[hide private]

lepl.matchers._test: Tests for the lepl.matchers package.
- lepl.matchers._test.combine: Tests for the combining matchers.
- lepl.matchers._test.core: Tests for the lepl.matchers.core module.
- lepl.matchers._test.derived
- lepl.matchers._test.error: Tests for the lepl.matchers.error module.
- lepl.matchers._test.float_bug: Tests for a weird bug when writing the float (rational at the time) matcher.
- lepl.matchers._test.memo
- lepl.matchers._test.operators: Tests for the lepl.matchers.operators module.
- lepl.matchers._test.separators: Tests for the lepl.matchers.separators module.
- lepl.matchers._test.support
- lepl.matchers._test.transform: Tests for the lepl.matchers.transform module
- lepl.matchers._test.variables: Tests for the lepl.matchers.variables module.
lepl.matchers._test3: Tests for the lepl.matchers package (Python 3 only - not include in final release)
- lepl.matchers._test3.support: Tests for the lepl.matchers.support module (duplicate, including Python 3 only syntax)
lepl.matchers.combine: Matchers that combine sub-matchers (And, Or etc).
lepl.matchers.complex: Complex matchers that are rearely used.
lepl.matchers.core: Matchers that embody fundamental, common actions.
lepl.matchers.derived: Matchers that are defined in terms of other matchers (ie the majority).
lepl.matchers.error: Error handling (generating an error while parsing).
lepl.matchers.matcher: Base class for matchers.
lepl.matchers.memo: Memoisation (both as described by Norvig 1991, giving Packrat parsers for non-left recursive grammars, and the equivalent described by Frost and Hafiz 2006 which allows left-recursive grammars to be used).
lepl.matchers.monitor: Matchers that interact with monitors.
lepl.matchers.operators: Support for operator syntactic sugar (and operator redefinition).
lepl.matchers.support: Support classes for matchers.
lepl.matchers.transform: A transformation is a function that modifies the result of calling a matcher once.
lepl.matchers.variables: Display information when matchers that are bound to variables are called.