'\"
'\" Generated from file 'page_util_flow\&.man' by tcllib/doctools with format 'nroff'
'\" Copyright (c) 2007 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>
'\"
.TH "page_util_flow" n 1\&.0 tcllib "Parser generator tools"
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.SH NAME
page_util_flow \- page dataflow/treewalker utility
.SH SYNOPSIS
package require \fBpage::util::flow ?0\&.2?\fR
.sp
package require \fBsnit\fR
.sp
\fB::page::util::flow\fR \fIstart\fR \fIflowvar\fR \fInodevar\fR \fIscript\fR
.sp
\fIflow\fR \fBvisit\fR \fInode\fR
.sp
\fIflow\fR \fBvisitl\fR \fInodelist\fR
.sp
\fIflow\fR \fBvisita\fR \fInode\fR\&.\&.\&.
.sp
.BE
.SH DESCRIPTION
.PP
This package provides a single utility command for easy dataflow based
manipulation of arbitrary data structures, especially abstract syntax
trees\&.
.SH API
.TP
\fB::page::util::flow\fR \fIstart\fR \fIflowvar\fR \fInodevar\fR \fIscript\fR
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\&.
.sp
The command makes no assumptions at all about the API of the structure
to be walked, except that that its parts, here called \fInodes\fR,
are identified by strings\&. These strings are taken as is, from the
arguments, and the body, and handed back to the body, without
modification\&.
.sp
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 \fIscript\fR\&.
.sp
The body is invoked first for the nodes in the start-set specified via
\fIstart\fR), 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\&.
.sp
The body is invoked in the context of the caller\&. The variable named
by \fInodevar\fR will be set to the current node, and the variable
named by \fIflowvar\fR 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,
\fBFLOW API\fR\&.
.sp
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\&.
.PP
.SH "FLOW API"
This section describes the API provided by the flow object made
accessible to the body script of \fB::page::util::flow\fR\&.
.TP
\fIflow\fR \fBvisit\fR \fInode\fR
Invoking this method requests that the node \fIn\fR is visited after
the current iteration\&.
.TP
\fIflow\fR \fBvisitl\fR \fInodelist\fR
Invoking this method requests that all the nodes found in the list
\fInodelist\fR are visited after the current iteration\&.
.TP
\fIflow\fR \fBvisita\fR \fInode\fR\&.\&.\&.
This is the variadic arguments form of the method \fBvisitl\fR, see
above\&.
.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 \fIpage\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
dataflow, graph walking, page, parser generator, text processing, tree walking
.SH CATEGORY
Page Parser Generator
.SH COPYRIGHT
.nf
Copyright (c) 2007 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>

.fi
