'\"
'\" Generated from file 'me_intro\&.man' by tcllib/doctools with format 'nroff'
'\" Copyright (c) 2005 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>
'\"
.TH "grammar::me_intro" 3tcl 0\&.1 tcllib "Grammar operations and usage"
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.SH NAME
grammar::me_intro \- Introduction to virtual machines for parsing token streams
.SH DESCRIPTION
This document is an introduction to and overview of the basic
facilities for the parsing and/or matching of \fItoken\fR
streams\&. One possibility often used for the token domain are
characters\&.
.PP
The packages themselves all provide variants of one
\fIvirtual machine\fR, called a \fImatch engine\fR (short
\fIME\fR), 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
(\fIAST\fR)\&.
.PP
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\&.
.PP
The relevant documents are:
.PP
.TP
\fBgrammar::me_vm\fR
Virtual machine specification\&.
.TP
\fBgrammar::me_ast\fR
Specification of various representations used for abstract syntax
trees\&.
.TP
\fBgrammar::me::util\fR
Utility commands\&.
.TP
\fBgrammar::me::tcl\fR
Singleton ME virtual machine implementation tied to Tcl for control
flow and stacks\&. Hardwired for pull operation\&. Uninteruptible during
processing\&.
.TP
\fBgrammar::me::cpu\fR
Object-based ME virtual machine implementation with explicit control
flow, and stacks, using bytecodes\&. Suspend/Resumable\&. Push/pull
operation\&.
.TP
\fBgrammar::me::cpu::core\fR
Core functionality for state manipulation and stepping used in the
bytecode based implementation of ME virtual machines\&.
.PP
.PP
.SH "BUGS, IDEAS, FEEDBACK"
This document, and the package it describes, will undoubtedly contain
bugs and other problems\&.
Please report such in the category \fIgrammar_me\fR of the
\fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&.
Please also report any ideas for enhancements you may have for either
package and/or documentation\&.
.PP
When proposing code changes, please provide \fIunified diffs\fR,
i\&.e the output of \fBdiff -u\fR\&.
.PP
Note further that \fIattachments\fR are strongly preferred over
inlined patches\&. Attachments can be made by going to the \fBEdit\fR
form of the ticket immediately after its creation, and then using the
left-most button in the secondary navigation bar\&.
.SH KEYWORDS
CFG, CFL, LL(k), PEG, TPDL, context-free grammar, context-free languages, expression, grammar, matching, parsing, parsing expression grammar, push down automaton, recursive descent, top-down parsing languages, transducer, virtual machine
.SH CATEGORY
Grammars and finite automata
.SH COPYRIGHT
.nf
Copyright (c) 2005 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>

.fi