page_util_flow(n) [osx man page]
page_util_flow(n) Parser generator tools page_util_flow(n) __________________________________________________________________________________________________________________________________________________ NAME
page_util_flow - page dataflow/treewalker utility SYNOPSIS
package require page::util::flow ?0.1? package require snit ::page::util::flow start flowvar nodevar script flow visit node flow visitl nodelist flow visita node... _________________________________________________________________ DESCRIPTION
This package provides a single utility command for easy dataflow based manipulation of arbitrary data structures, especially abstract syn- tax trees. API
::page::util::flow start flowvar nodevar script This command contains the core logic to drive the walking of an arbitrary data structure which can partitioned into separate parts. Examples of such structures are trees and graphs. The command makes no assumptions at all about the API of the structure to be walked, except that that its parts, here called nodes, are identified by strings. These strings are taken as is, from the arguments, and the body, and handed back to the body, without modification. Access to the actual data structure, and all decisions regarding which nodes to visit in what order are delegated to the body of the loop, i.e. the script. The body is invoked first for the nodes in the start-set specified via start), and from then on for the nodes the body has requested to be visited. The command stops when the set of nodes to visit becomes empty. Note that a node can be visited more than once. The body has complete control about this. The body is invoked in the context of the caller. The variable named by nodevar will be set to the current node, and the variable named by flowvar will be set to the command of the flow object through which the body can request the nodes to visit next. The API provided by this object is described in the next section, FLOW API. Note that the command makes no promises regarding the order in which nodes are visited, excpt that the nodes requested to be visited by the current iteration will be visited afterward, in some order. FLOW API
This section describes the API provided by the flow object made accessible to the body script of ::page::util::flow. flow visit node Invoking this method requests that the node n is visited after the current iteration. flow visitl nodelist Invoking this method requests that all the nodes found in the list nodelist are visited after the current iteration. flow visita node... This is the variadic arguments form of the method visitl, see above. BUGS, IDEAS, FEEDBACK This document, will undoubtedly contain bugs and other problems. Please report such in the category page of the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have. KEYWORDS
dataflow, graph walking, page, parser generator, text processing, tree walking CATEGORY
Page Parser Generator COPYRIGHT
Copyright (c) 2007 Andreas Kupries <andreas_kupries@users.sourceforge.net> page 1.0 page_util_flow(n)
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page_util_peg(n) Parser generator tools page_util_peg(n) __________________________________________________________________________________________________________________________________________________ NAME
page_util_peg - page PEG transformation utilities SYNOPSIS
package require page::util::peg ?0.1? package require snit ::page::util::peg::symbolNodeOf tree node ::page::util::peg::symbolOf tree node ::page::util::peg::updateUndefinedDueRemoval tree ::page::util::peg::flatten treequery tree ::page::util::peg::getWarnings tree ::page::util::peg::printWarnings msg ::page::util::peg::peOf tree eroot ::page::util::peg::printTclExpr pe _________________________________________________________________ DESCRIPTION
This package provides a few common operations to PEG transformations. They assume a Normalized PE Grammar Tree as input, see the package page::util::norm::peg, possibly augmented with attributes coming from transformations not in conflict with the base definition. API
::page::util::peg::symbolNodeOf tree node Given an arbitrary expression node in the AST tree it determines the node (itself or an ancestor) containing the name of the nonter- minal symbol the node belongs to, and returns its id. The result is either the root of the tree (for the start expression), or a definition node. ::page::util::peg::symbolOf tree node As ::page::util::peg::symbolNodeOf, but returns the symbol name instead of the node. ::page::util::peg::updateUndefinedDueRemoval tree The removal of nodes in the AST tree can cause symbols to lose one or more users. A used by B and C, B is reachable, C is not, so A now loses the node in the expression for C calling it, or rather, not calling it anymore. This command updates the cross-references and which nonterminals are now undefined. ::page::util::peg::flatten treequery tree This commands flattens nested sequence and choice operators in the AST tree, re-using the treeql object treequery to run the query determining which nodes to cut. ::page::util::peg::getWarnings tree This command looks at the attributes of the AST tree for problems with the grammar and issues warnings. They do not prevent us from writing the grammar, but still represent problems with it the user should be made aware of. The result of the command is a dictionary mapping nonterminal names to their associated warnings. ::page::util::peg::printWarnings msg The argument of the command is a dictionary mapping nonterminal names to their associated warnings, as generated by, for example, the command ::page::util::peg::getWarnings. The warnings contained therein are formatted and then printed via the log command page_info. This means that this command can be used only from within a plugin managed by the package page::pluginmgr. ::page::util::peg::peOf tree eroot This command converts the parsing expression starting at the node eroot in the AST tree into a nested list. The exact syntax of this list specified by the package grammar::peg. ::page::util::peg::printTclExpr pe This command converts the parsing expression contained in the nested list pe into a Tcl string which can be placed into a Tcl script. See the package grammar::peg for the exact syntax of pe. BUGS, IDEAS, FEEDBACK This document, will undoubtedly contain bugs and other problems. Please report such in the category page of the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have. KEYWORDS
PEG, page, parser generator, parsing expression grammar, text processing, transformation CATEGORY
Page Parser Generator COPYRIGHT
Copyright (c) 2007 Andreas Kupries <andreas_kupries@users.sourceforge.net> page 1.0 page_util_peg(n)