


doctools::tcl::parse(n)Documentation toolsdoctools::tcl::parse(n)


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NAME
       doctools::tcl::parse - Processing text in 'subst -novariables' format

SYNOPSIS
       package require Tcl  8.4

       package require snit

       package require fileutil

       package require logger

       package require struct::list

       package require struct::stack

       package require struct::set

       package require treeql

       ::doctools::tcl::parse text tree text ?root?

       ::doctools::tcl::parse file tree path ?root?

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DESCRIPTION
       This  package provides commands for parsing text with embedded Tcl com-
       mands as accepted by the Tcl builtin command  subst  -novariables.  The
       result of the parsing is an abstract syntax tree.

       This  is  an  internal package of doctools, for use by the higher level
       parsers processing the docidx, doctoc, and doctools markup languages.

API
       ::doctools::tcl::parse text tree text ?root?
              The command takes the text and parses it  under  the  assumption
              that  it contains a string acceptable to the Tcl builtin command
              subst -novariables. Errors are thrown otherwise during the pars-
              ing.  The  format  used for these errors in described in section
              Error format.

              The command returns the empty string as it  result.  The  actual
              result  of  the parsing is entered into the tree structure tree,
              under the node root.  If root is not specified the root of  tree
              is  used.  The  tree  has  to exist and be the command of a tree
              object which supports the same methods as trees created  by  the
              package struct::tree.

              In case of errors tree will be left in an undefined state.





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doctools::tcl::parse(n)Documentation toolsdoctools::tcl::parse(n)


       ::doctools::tcl::parse file tree path ?root?
              The same as text, except that the text to parse is read from the
              file specified by path.


ERROR FORMAT
       When the parser encounters a problem in the  input  it  will  throw  an
       error using the format described here.

       [1]    The  message will contain the reason for the problem (unexpected
              character or end of input in input), the character in  question,
              if  any,  and the line and column the problem was found at, in a
              human readable form. This part is not documented further as  its
              format  may  change as we see fit. It is intended for human con-
              sumption, not machine.

       [2]    The error code however will contain a machine-readable represen-
              tation  of the problem, in the form of a 5-element list contain-
              ing, in the order listed below

              [1]    the constant string doctools::tcl::parse

              [2]    the cause of the problem, one of

                      char   Unexpected character in input

                      eof    Unexpected end of the input

              [3]    The location of the problem as offset from the  beginning
                     of  the  input, counted in characters. Note: Line markers
                     count as one character.

              [4]    The line the problem was found on (counted from 1 (one)),

              [5]    The  column  the  problem  was  found  at (counted from 0
                     (zero))


TREE STRUCTURE
       After successfully parsing a string the generated tree  will  have  the
       following structure:

       [1]    In  the following items the word 'root' refers to the node which
              was specified as the root of the tree when invoking either  text
              or file. This may be the actual root of the tree.

       [2]    All  the  following items further ignore the possibility of pre-
              existing attributes in the  pre-existing  nodes.  If  attributes
              exists  with the same names as the attributes used by the parser
              the pre-existing values are written over. Attributes with  names
              not clashing with the parser's attributes are not touched.

       [3]    The root node has no attributes.




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doctools::tcl::parse(n)Documentation toolsdoctools::tcl::parse(n)


       [4]    All other nodes have the attributes

              type   The  value  is  a  string from the set { Command , Text ,
                     Word }

              range  The value is either empty or a 2-element list  containing
                     integer numbers. The numbers are the offsets of the first
                     and last character  in  the  input  text,  of  the  token
                     described by the node,.

              line   The  value  is  an  integer, it describes the line in the
                     input the token described by the node ends on. Lines  are
                     counted from 1 (one).

              col    The  value  is an integer, it describes the column in the
                     line in the input the token described by  the  node  ends
                     on. Columns are counted from 0 (zero).

       [5]    The  children of the root, if any, are of type Command and Text,
              in semi-alternation. This means: After a  Text  node  a  Command
              node  has  to  follow, and anything can follow a Command node, a
              Text or other Command node.

       [6]    The children of a Command node, if any, are of type Command, and
              Text, and Word, they describe the arguments of the command.

       [7]    The  children of a Word node, if any, are of type Command, Text,
              in semi-alternation. This means: After a  Text  node  a  Command
              node  has  to  follow, and anything can follow a Command node, a
              Text or other Command node.

       [8]    A Word node without children represents the empty string.

       [9]    All Text nodes are leaves of the tree.

       [10]   All leaves of the tree are either Text or Command  nodes.   Word
              nodes cannot be leaves.


BUGS, IDEAS, FEEDBACK
       This  document,  and the package it describes, will undoubtedly contain
       bugs and other problems.  Please report such in the  category  doctools
       of       the       Tcllib       SF       Trackers       [http://source-
       forge.net/tracker/?group_id=12883].  Please also report any  ideas  for
       enhancements you may have for either package and/or documentation.

KEYWORDS
       Tcl syntax, command, doctools, parser, subst, word

CATEGORY
       Documentation tools

COPYRIGHT
       Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>



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