Xbt

• Index

Contents

• Functions
• Tables

Modules

• xbt.util
• xbt.path
• xbt.graph
• xbt

Module xbt.path

Submodule for paths.

The submodule path contains all operations for operating on paths in the XBT.

Info:

• Copyright: 2015, Matthias Hölzl
• License: MIT, see the file LICENSE.md.
• Author: Matthias Hölzl

Functions

new (id, ...)	Generate a new path starting at the root of the XBT.
new_immutable (id, ...)	Generate a new immutable path starting at the root of the XBT.
__eq (p1, p2)	Paths are compared using value equality.
__tostring (p)	Convert a path to string
down (p)	Descend one level deeper into the tree.
right (p)	Move to the next sibling of the current node.
up (p)	Move up one level in a tree.
copy (p, extension)	Copy a path.
root_path ()	Return the root path for a path.
is_path (p)	Check whether a value represents a path.

Tables

meta	The metatable for path objects.

Functions

new (id, ...)

Generate a new path starting at the root of the XBT.

Parameters:

• id The ID of the agent which is evaluating the XBT. If no argument is provided for id, then a random UUID is generated, so that empty paths allocated without any arguments are never equal to each other.
• ... Any number of positive integers can be passed as arguments to the function and will be used as the value for the result path.

Returns:

A new path.

new_immutable (id, ...)

Generate a new immutable path starting at the root of the XBT.

Parameters:

• id The ID of the agent which is evaluating the XBT. If no argument is provided for id, then a random UUID is generated, so that empty paths allocated without any arguments are never equal to each other.
• ... Any number of positive integers can be passed as arguments to the function and will be used as the value for the result path.

Returns:

A new path.

__eq (p1, p2)

Paths are compared using value equality.

Parameters:

• p1 A path.
• p2 Another path.

Returns:

true if p1 and p2 point to the same location in the tree, false otherwise. Does not differentiate whether the paths differ in their immutable flag.

__tostring (p)

Convert a path to string

Parameters:

• p A path.

Returns:

A string representation of p

down (p)

Descend one level deeper into the tree.

Parameters:

• p A path pointing to a node n in an XBT.

Returns:

The value of p modified to point to the first child of n.

right (p)

Move to the next sibling of the current node.

Parameters:

• p A path pointing to a node n in an XBT.

Returns:

The value of p modified to point to the right sibling of n.

up (p)

Move up one level in a tree.

Parameters:

• p A path pointing to a non-root node n of an XBT.

Returns:

The value of p modified to point to the parent of n.

copy (p, extension)

Copy a path.

Parameters:

• p A path pointing to a node in an XBT.
• extension An extension of the path that will be added to the copy. Either a positive integer for a single step or an array of positive integers for a relative path. No extension is added if extension is falsy. Default is nil.

Returns:

A copy of the path p.

root_path ()

Return the root path for a path. When running the same XBT for multiple objects we use the first component of the path as object id, so that we have a forest of execution trees.

Returns:

A new path containing only the first element of the given path.

is_path (p)

Check whether a value represents a path.

Parameters:

• p The value to be tested.

Returns:

A Boolean indicating whether p is a path. This decision is made by checking whether the metatable of p is the one defined for paths, so path-like objects are not accepted.

Tables

meta

The metatable for path objects.

Fields:

• __index