Страницы справочника OS X

Эта страница руководства для  версии 10.9 Mac OS X

Читать страницы руководства

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 syntax 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)