1page_util_flow(n)           Parser generator tools           page_util_flow(n)
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NAME

8       page_util_flow - page dataflow/treewalker utility
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SYNOPSIS

11       package require page::util::flow  ?0.1?
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13       package require snit
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15       ::page::util::flow start flowvar nodevar script
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17       flow visit node
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19       flow visitl nodelist
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21       flow visita node...
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DESCRIPTION

26       This  package provides a single utility command for easy dataflow based
27       manipulation of arbitrary data structures, especially  abstract  syntax
28       trees.
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API

31       ::page::util::flow start flowvar nodevar script
32              This  command contains the core logic to drive the walking of an
33              arbitrary data structure which  can  partitioned  into  separate
34              parts. Examples of such structures are trees and graphs.
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36              The  command  makes  no  assumptions at all about the API of the
37              structure to be walked, except that that its parts, here  called
38              nodes, are identified by strings. These strings are taken as is,
39              from the arguments, and the body, and handed back to  the  body,
40              without modification.
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42              Access to the actual data structure, and all decisions regarding
43              which nodes to visit in what order are delegated to the body  of
44              the loop, i.e. the script.
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46              The  body is invoked first for the nodes in the start-set speci‐
47              fied via start), and from then on for the  nodes  the  body  has
48              requested to be visited. The command stops when the set of nodes
49              to visit becomes empty. Note that a node  can  be  visited  more
50              than once. The body has complete control about this.
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52              The  body  is invoked in the context of the caller. The variable
53              named by nodevar will be set to the current node, and the  vari‐
54              able  named  by  flowvar  will be set to the command of the flow
55              object through which the body can request  the  nodes  to  visit
56              next.  The  API provided by this object is described in the next
57              section, FLOW API.
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59              Note that the command makes no promises regarding the  order  in
60              which  nodes  are  visited, excpt that the nodes requested to be
61              visited by the current iteration will be visited  afterward,  in
62              some order.
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FLOW API

65       This  section describes the API provided by the flow object made acces‐
66       sible to the body script of ::page::util::flow.
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68       flow visit node
69              Invoking this method requests that the node n is  visited  after
70              the current iteration.
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72       flow visitl nodelist
73              Invoking  this  method  requests that all the nodes found in the
74              list nodelist are visited after the current iteration.
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76       flow visita node...
77              This is the variadic arguments form of the  method  visitl,  see
78              above.
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BUGS, IDEAS, FEEDBACK

81       This  document,  will  undoubtedly  contain  bugs  and  other problems.
82       Please report such in the category  page  of  the  Tcllib  SF  Trackers
83       [http://sourceforge.net/tracker/?group_id=12883].   Please  also report
84       any ideas for enhancements you may have.
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KEYWORDS

87       dataflow, graph walking, page, parser generator, text processing,  tree
88       walking
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91       Copyright (c) 2007 Andreas Kupries <andreas_kupries@users.sourceforge.net>
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96page                                  1.0                    page_util_flow(n)
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