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Class Pxp_dtd.namespace_manager

class namespace_manager : object .. end
This class manages mappings from URIs to normalized prefixes. For every namespace a namespace_manager object contains a set that maps various URI's to the same normalized prefix np:
 uri1 |-> np, uri2 |-> np, ..., uriN |-> np 
The normalized prefix np is characterstical of the namespace, and identifies the namespace uniquely. The first URI uri1 is the primary URI, the other URIs are aliases.

In order to create an empty namespace, call Pxp_dtd.create_namespace_manager.

See Intro_namespaces for an introduction to namespaces and more links to other explanations about namespace managers.

The following operations are supported:

  • add_namespace np uri: adds a new mapping uri |-> np to the manager. Neither np nor uri must already be part of another mapping in the manager.
  • add_uri np uri: adds a new alias uri for an existing namespace which is identified by the normprefix np. The normprefix np must already be part of a mapping which is then extended by this method.
  • lookup_or_add_namespace p uri: If there is already some mapping uri |-> np, the normprefix np is simply returned ("lookup"). In this case p is ignored. Otherwise uri is not yet mapped, and in this case some unique np must be found such that uri |-> np can be added (add_namespace). First, the passed prefix p is tried. If p is free, it can be taken as new normprefix: np = p. Otherwise some number n is found such that the concatenation p ^ n is free: np = p ^ n. The operation returns np.
Encodings: prefixes and URIs are always encoded in the default encoding of the document

method add_namespace : string -> string -> unit
add_namespace np uri: adds a new namespace to the object. The namespace is identified by the normprefix np and contains initially the primary URI uri. The method fails (Namespace_error) if either np already identifies some namespace or if uri is already member of some namespace. Nothing happens if uri is the sole member of the namespace np. It is required that np <> "".
method add_uri : string -> string -> unit
add_uri np uri: adds uri as alias URI to the namespace identified by the normprefix np (see above for detailed semantics). The method raises Namespace_prefix_not_managed if the normprefix np is unknown to the object, and it fails (Namespace_error) if the uri is member of a different namespace. Nothing happens if the uri is already member of the namespace np.

Change in PXP 1.2: Using exception Namespace_prefix_not_managed instead of Not_found.

method lookup_or_add_namespace : string -> string -> string
lookup_or_add_namespace p uri: first, the method looks up if the namespace for uri does already exist. If so, p is ignored, and the method returns the normprefix identifying the namespace. Otherwise, a new namespace is added for some normprefix np which initially contains uri. The normprefix np is calculated upon p serving as suggestion for the normprefix. The method returns the normprefix.
method get_primary_uri : string -> string
Return the primary URI for a normprefix, or raises Namespace_prefix_not_managed. get_uri "" raises always this exception.
method get_uri_list : string -> string list
Return all URIs for a normprefix, or [] if the normprefix is unused. get_uri_list "" returns always []. The last URI of the returned list is the primary URI.
method get_normprefix : string -> string
Return the normprefix for a URI, or raises Namespace_not_managed.
method iter_namespaces : (string -> unit) -> unit
Iterates over all namespaces contained in the object, and calls the passed function for every namespace. The argument of the invoked function is the normprefix of the namespace.
method as_declaration : (string * string) list
Returns the list of normprefixes and primary URIs. Useful to create the corresponding namespace scope, e.g.
new namespace_scope_impl mng None (mng#as_declaration) 

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