NAME

       grammar::me::util - AST utilities

SYNOPSIS

       package require Tcl  8.4

       package require grammar::me::util  ?0.1?

       ::grammar::me::util::ast2tree ast tree ?root?

       ::grammar::me::util::ast2etree ast mcmd tree ?root?

       mcmd lc location

       mcmd tok from ?to?

       ::grammar::me::util::tree2ast tree ?root?

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DESCRIPTION

       This  package  provides a number of utility command for the conversion between the various
       representations of abstract syntax trees as specified in the document grammar::me_ast.

       ::grammar::me::util::ast2tree ast tree ?root?
              This command converts an ast from value to object representation. All nodes in  the
              ast  will be converted into nodes of this tree, with the root of the AST a child of
              the node root. If this node is not explicitly specified the root  of  the  tree  is
              used.  Existing  content of tree is not touched, i.e.  neither removed nor changed,
              with the exception of the specified root node, which will gain a new child.

       ::grammar::me::util::ast2etree ast mcmd tree ?root?
              This command is like ::grammar::me::util::ast2tree, except that the  result  is  in
              the  extended  object  representation of the input AST.  The source of the extended
              information is the command prefix mcmd.  It has to understand two methods, lc,  and
              tok, with the semantics specified below.

              mcmd lc location
                     Takes the location of a token given as offset in the input stream and return
                     a 2-element list containing the associated line number and column index,  in
                     this order.

              mcmd tok from ?to?
                     Takes  one  or  two  locations from and to as offset in the input stream and
                     returns a Tcl list containing the specified part of the input  stream.  Both
                     location  are inclusive. If to is not specified it will default to the value
                     of from.

                     Each element of the returned list  is  a  list  containing  the  token,  its
                     associated lexeme, the line number, and column index, in this order.

       Both  the ensemble command ::grammar::me::tcl provided by the package grammar::me::tcl and
       the objects command created by the package ::grammar::me::cpu fit the above specification.

       ::grammar::me::util::tree2ast tree ?root?
              This command converts an ast in (extended) object representation into a  value  and
              returns  it.   If  a  root  node  is  specified the AST is generated from that node
              downward. Otherwise the root of the tree object is used as the starting point.

BUGS, IDEAS, FEEDBACK

       This document, and the package it describes,  will  undoubtedly  contain  bugs  and  other
       problems.   Please  report  such  in  the  category  grammar_me  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.

KEYWORDS

       abstract syntax tree, syntax tree, tree

CATEGORY

       Grammars and finite automata

COPYRIGHT

       Copyright (c) 2005 Andreas Kupries <andreas_kupries@users.sourceforge.net>