doctools::tcl::parse(3tcl) Documentation tools doctools::tcl::parse(3tcl)______________________________________________________________________________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 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.
::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.
[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>
doctools2base 1 doctools::tcl::parse(3tcl)
