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

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

COPYRIGHT

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