me_intro(3tcl) [debian man page]
grammar::me_intro(3tcl) Grammar operations and usage grammar::me_intro(3tcl) __________________________________________________________________________________________________________________________________________________ NAME
grammar::me_intro - Introduction to virtual machines for parsing token streams DESCRIPTION
This document is an introduction to and overview of the basic facilities for the parsing and/or matching of token streams. One possibility often used for the token domain are characters. The packages themselves all provide variants of one virtual machine, called a match engine (short 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 (AST). 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. The relevant documents are: grammar::me_vm Virtual machine specification. grammar::me_ast Specification of various representations used for abstract syntax trees. grammar::me::util Utility commands. grammar::me::tcl Singleton ME virtual machine implementation tied to Tcl for control flow and stacks. Hardwired for pull operation. Uninteruptible during processing. grammar::me::cpu Object-based ME virtual machine implementation with explicit control flow, and stacks, using bytecodes. Suspend/Resumable. Push/pull operation. grammar::me::cpu::core Core functionality for state manipulation and stepping used in the bytecode based implementation of ME virtual machines. BUGS, IDEAS, FEEDBACK This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category gram- mar_me of the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have for either package and/or documentation. KEYWORDS
CFG, CFL, LL(k), PEG, TPDL, context-free grammar, context-free languages, expression, grammar, matching, parsing, parsing expression gram- mar, push down automaton, recursive descent, top-down parsing languages, transducer, virtual machine CATEGORY
Grammars and finite automata COPYRIGHT
Copyright (c) 2005 Andreas Kupries <andreas_kupries@users.sourceforge.net> grammar_me 0.1 grammar::me_intro(3tcl)
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grammar::me::util(3tcl) Grammar operations and usage grammar::me::util(3tcl) __________________________________________________________________________________________________________________________________________________ NAME
grammar::me::util - AST utilities SYNOPSIS
package require Tcl 8.4 package require grammar::me::util ?0.1? ::grammar::me::util::ast2tree ast tree ?root? ::grammar::me::util::ast2etree ast mcmd tree ?root? mcmd lc location mcmd tok from ?to? ::grammar::me::util::tree2ast tree ?root? _________________________________________________________________ DESCRIPTION
This package provides a number of utility command for the conversion between the various representations of abstract syntax trees as speci- fied in the document grammar::me_ast. ::grammar::me::util::ast2tree ast tree ?root? This command converts an ast from value to object representation. All nodes in the ast will be converted into nodes of this tree, with the root of the AST a child of the node root. If this node is not explicitly specified the root of the tree is used. Existing content of tree is not touched, i.e. neither removed nor changed, with the exception of the specified root node, which will gain a new child. ::grammar::me::util::ast2etree ast mcmd tree ?root? This command is like ::grammar::me::util::ast2tree, except that the result is in the extended object representation of the input AST. The source of the extended information is the command prefix mcmd. It has to understand two methods, lc, and tok, with the semantics specified below. mcmd lc location Takes the location of a token given as offset in the input stream and return a 2-element list containing the associated line number and column index, in this order. mcmd tok from ?to? Takes one or two locations from and to as offset in the input stream and returns a Tcl list containing the specified part of the input stream. Both location are inclusive. If to is not specified it will default to the value of from. Each element of the returned list is a list containing the token, its associated lexeme, the line number, and column index, in this order. Both the ensemble command ::grammar::me::tcl provided by the package grammar::me::tcl and the objects command created by the package ::grammar::me::cpu fit the above specification. ::grammar::me::util::tree2ast tree ?root? This command converts an ast in (extended) object representation into a value and returns it. If a root node is specified the AST is generated from that node downward. Otherwise the root of the tree object is used as the starting point. BUGS, IDEAS, FEEDBACK This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category gram- mar_me of the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have for either package and/or documentation. KEYWORDS
abstract syntax tree, syntax tree, tree CATEGORY
Grammars and finite automata COPYRIGHT
Copyright (c) 2005 Andreas Kupries <andreas_kupries@users.sourceforge.net> grammar_me 0.1 grammar::me::util(3tcl)