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







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








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?












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.









  
::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







  

  
Unexpected character in input

  

  
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))












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







  

  
The value is a string from the set { Command , Text , Word }

  

  
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,.

  

  
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).

  

  
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.










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.








Tcl syntax, command, doctools, parser, subst, word








Documentation tools








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








  

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