blt_treecreate(3) [debian man page]

Blt_TreeCreate(3)					      BLT Library Procedures						 Blt_TreeCreate(3)

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NAME

       Blt_TreeCreate - Create tree data object.

SYNOPSIS

       #include <bltTree.h>

       int
       Blt_TreeCreate(interp, name, tokenPtr)

ARGUMENTS

       Tcl_Interp   *interp   (in)	Interpreter to report results back to.

       const char   *name     (in)	Name of the new tree.  Can be qualified by a namespace.

       Blt_Tree     *tokenPtr (out)	If not NULL, points to location to store the client tree token.
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DESCRIPTION

       This procedure creates a C-based tree data object and optionally returns a token to it.	The arguments are as follows:

       interp	 Interpreter to report results back to.  If an error occurs, then interp->result will contain an error message.

       name	 Name  of the new tree object.	You can think of name as the memory address of the object.  It's a unique name that identifies the
		 tree object.  No tree object name can already exist.  Name can be qualified by a namespace such as fred::myTree.  If no namespace
		 qualifier  is	used, the tree will be created in the current namespace, not the global namespace.  If a qualifier is present, the
		 namespace must already exist.

       tokenPtr  Holds the returned token.  TokenPtr points to a location where it is stored. Tree tokens are used to work with the  tree  object.
		 If NULL, no token is allocated.  You can later use Tcl_TreeGetToken to obtain a token.

       The new tree data object created will initially contain only a root node.  You can add new nodes with Blt_TreeCreateNode.

       Optionally  a  token  for the tree data object is returned.  Tree data objects can be shared.  For example, the tree and hiertable commands
       may be accessing the same tree data object.  Each client grabs a token that is associated with the tree.  When all tokens are released (see
       Blt_TreeReleaseToken) the tree data object is automatically destroyed.

RETURNS

       A  standard Tcl result is returned.  If TCL_ERROR is returned, then interp->result will contain an error message.  The following errors may
       occur:

       o  There already exists a tree by the same name as name. You can use Tcl_TreeExists to determine if a tree exists beforehand.

       o  The tree name is prefixed by a namespace that doesn't exist.	If you qualified the tree name with a namespace, the namespace must exist.
	  Unlike Tcl procs and variables, the namespace is not automatically created for you.

       o  Memory can't be allocated for the tree or token.

EXAMPLE

       The following example creates a new

	      Blt_Tree token;

	      if (Blt_TreeCreate(interp, "myTree", &token) != TCL_OK) {
		  return TCL_ERROR;
	      }
	      printf("tree is %s
", Blt_TreeName(token));

KEYWORDS

       Tcl_TreeGetToken, Tcl_TreeExists, Tcl_TreeReleaseToken

BLT
									2.4							 Blt_TreeCreate(3)

grammar::me_ast(n)					   Grammar operations and usage 					grammar::me_ast(n)

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NAME

       grammar::me_ast - Various representations of ASTs

DESCRIPTION

       This  document  specifies  various representations for the abstract syntax trees (short AST) generated by instances of ME virtual machines,
       independent of variant.	Please go and read the document grammar::me_intro first if you do not know what a ME virtual machine is.

       ASTs and all the representations we specify distinguish between two types of nodes, namely:

       Terminal
	      Terminal nodes refer to the terminal symbols found in the token stream. They are always leaf nodes. I.e. terminal nodes  never  have
	      children.

       Nonterminal
	      Nonterminal  nodes  represent a nonterminal symbol of the grammar used during parsing. They can occur as leaf and inner nodes of the
	      tree.

       Both types of nodes carry basic range information telling a user which parts of the input are covered by the node by providing the location
       of the first and last tokens found within the range. Locations are provided as non-negative integer offsets from the beginning of the token
       stream, with the first token found in the stream located at offset 0 (zero).

       The root of an AS tree can be either a terminal or nonterminal node.

AST VALUES

       This representation of ASTs is a Tcl list. The main list represents the root node of the tree, with the	representations  of  the  children
       nested within.

       Each  node  is represented by a single Tcl list containing three or more elements. The first element is either the empty string or the name
       of a nonterminal symbol (which is never the empty string). The second and third elements are then the  locations  of  the  first  and  last
       tokens.	 Any  additional elements after the third are then the representations of the children, with the leftmost child first, i.e. as the
       fourth element of the list representing the node.

AST OBJECTS

       In this representation an AST is represented by a Tcl object command whose API is compatible to the tree objects provided  by  the  package
       struct::tree. I.e it has to support at least all of the methods described by that package, and may support more.

       Because of this the remainder of the specifications is written using the terms of struct::tree.

       Each  node  of the AST directly maps to a node in the tree object. All data beyond the child nodes, i.e. node type and input locations, are
       stored in attributes of the node in the tree object. They are:

       type   The type of the AST node. The recognized values are terminal and nonterminal.

       range  The locations of the first and last token of the terminal data in the input covered by the node. This is a list containing two loca-
	      tions.

       detail This attribute is present only for nonterminal nodes. It contains the name of the nonterminal symbol stored in the node.

EXTENDED AST OBJECTS

       Extended AST objects are like AST objects, with additional information.

       detail This  attribute is now present at all nodes. Its contents are unchanged for nonterminal nodes. For terminal nodes it contains a list
	      describing all tokens from the input which are covered by the node.

	      Each element of the list contains the token name, the associated lexeme attribute, line number, and column index, in this order.

       range_lc
	      This new attribute is defined for all nodes, and contains the locations from attribute range translated into line number and  column
	      index. Lines are counted from 1, columns are counted from 0.

BUGS, IDEAS, FEEDBACK
       This  document,	and  the package it describes, will undoubtedly contain bugs and other problems.  Please report such in the category gram-
       mar_me 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

       AST, abstract syntax tree

COPYRIGHT

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

grammar_me								0.1							grammar::me_ast(n)