[comment {-*- tcl -*- doctools manpage}]
[manpage_begin grammar::me_intro n 0.2]
[keywords CFG]
[keywords CFL]
[keywords {context-free grammar}]
[keywords {context-free languages}]
[keywords expression]
[keywords grammar]
[keywords LL(k)]
[keywords matching]
[keywords parsing]
[keywords {parsing expression grammar}]
[keywords PEG]
[keywords {push down automaton}]
[keywords {recursive descent}]
[keywords {top-down parsing languages}]
[keywords TPDL]
[keywords transducer]
[keywords {virtual machine}]
[copyright {2005 Andreas Kupries <andreas_kupries@users.sourceforge.net>}]
[moddesc   {Grammar operations and usage}]
[titledesc {Introduction to virtual machines for parsing token streams}]
[category  {Grammars and finite automata}]
[description]

This document is an introduction to and overview of the basic
facilities for the parsing and/or matching of [term token]
streams. One possibility often used for the token domain are
characters.

[para]

The packages themselves all provide variants of one

[term {virtual machine}], called a [term {match engine}] (short

[term ME]), which has all the facilities needed for the matching and
parsing of a stream, and which are either controlled directly, or are
customized with a match program. The virtual machine is basically a
pushdown automaton, with additional elements for backtracking and/or
handling of semantic data and construction of abstract syntax trees
([term AST]).

[para]

Because of the high degree of similarity in the actual implementations
of the aforementioned virtual machine and the data structures they
receive and generate these common parts are specified in a separate
document which will be referenced by the documentation for packages
actually implementing it.

[para]

The relevant documents are:

[para]
[list_begin definitions]

[def [package grammar::me_vm]]

Virtual machine specification.

[def [package grammar::me_ast]]

Specification of various representations used for abstract syntax
trees.

[def [package grammar::me::util]]

Utility commands.

[def [package grammar::me::tcl]]

Singleton ME virtual machine implementation tied to Tcl for control
flow and stacks. Hardwired for pull operation. Uninteruptible during
processing.

[def [package grammar::me::cpu]]

Object-based ME virtual machine implementation with explicit control
flow, and stacks, using bytecodes. Suspend/Resumable. Push/pull
operation.

[def [package grammar::me::cpu::core]]

Core functionality for state manipulation and stepping used in the
bytecode based implementation of ME virtual machines.

[list_end]
[para]

[vset CATEGORY grammar_me]
[include ../common-text/feedback.inc]
[manpage_end]
