Provided by: tcllib_1.19-dfsg-2_all 
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
package require doctools::tcl::parse
::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 Trackers
[http://core.tcl.tk/tcllib/reportlist]. Please also report any ideas for enhancements you
may have for either package and/or documentation.
When proposing code changes, please provide unified diffs, i.e the output of diff -u.
Note further that attachments are strongly preferred over inlined patches. Attachments can
be made by going to the Edit form of the ticket immediately after its creation, and then
using the left-most button in the secondary navigation bar.
KEYWORDS
Tcl syntax, command, doctools, parser, subst, word
CATEGORY
Documentation tools
COPYRIGHT
Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>