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



______________________________________________________________________________

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?

_________________________________________________________________

DESCRIPTION
       This package provides commands for parsing text with embedded Tcl
       commands 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
              parsing. 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.

       ::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
              consumption, not machine.

       [2]    The error code however will contain a machine-readable
              representation of the problem, in the form of a 5-element list
              containing, 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.

       [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://sourceforge.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>




doctools2base                          1               doctools::tcl::parse(n)
