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.
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>