Rule: Difference between revisions

Revision as of 18:26, 16 August 2013

Node: A node is the most elementary unit in the graph. It is the result of the tokenization process, and corresponds to the notion of "lexical item". At the surface level, a natural language sentence is considered a list of nodes, and a UNL graph a set of relations between nodes.
Relation: In order to form a natural language sentence or a UNL graph, nodes are inter-related by relations. In the UNL framework, there can be three different types of relations: linear, syntactic or semantic.
Hyper-Node: A hyper-node is a sub-graph, i.e., a node containing relations between nodes.
Hyper-Relation: A hyper-relation is a relation between relations.

Basic symbols used in UNL grammar rules
Symbol	Definition	Example
^	not	^a = not a
{ \| }	or	{a\|b} = a or b
%	index for nodes, attributes and values	%x (see below)
#	index for sub-NLWs	#01 (see below)
=	attribute-value assignment	POS=NOU
!	rule trigger	!PLR
&	merge operator	%x&%y
?	dictionary lookup operator	?[a]
“ “	string	"went"
[ ]	natural language entry (headword)	[go]
[[ ]]	UW	[[to go(icl>to move)]]
( )	node	(a)
//	regular expression	/a{2,3}/ = aa,aaa

The differences between "", [] and [[]]: Double quotes are always used to represent strings: "a" will match only the string "a"; Simple square brackets are always used to represent natural language entries (headwords) in the dictionary: [a] will match the node associated to the entry [a] retrieved from the dictionary, no matter its current realization, which may be affected by other rules (the original [a] may have been replaced, for instance, by "b", but will still be indexed to the entry [a]); Double square brackets are always used to represent UWs: [[a]] will match the node associated to the UW [[a]]

Predefined values (assigned by default): SCOPE - Scope; SHEAD - Sentence head (the beginning of a sentence); STAIL - Sentence tail (the end of a sentence); CHEAD - Scope head (the beginning of a scope); CTAIL - Scope tail (the end of a scope); TEMP - Temporary entry (entry not found in the dictionary); DIGIT - Any sequence of digits (i.e.: 0,1,2,3,4,5,6,7,8,9)

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-N-rules (normalization rules) and T-rules (transformation rules) follow the very general formalism
+== Basic concepts ==
+;[[Node]]
+:A node is the most elementary unit in the graph. It is the result of the [[tokenization]] process, and corresponds to the notion of "lexical item". At the surface level, a natural language sentence is considered a list of nodes, and a UNL graph a set of relations between nodes.
+;[[Relation]]
+:In order to form a natural language sentence or a UNL graph, nodes are inter-related by relations. In the UNL framework, there can be three different types of relations: linear, syntactic or semantic.
+;[[Hyper-Node]]
+:A hyper-node is a sub-graph, i.e., a node containing relations between nodes.
+;[[Hyper-Relation]]
+:A hyper-relation is a relation between relations.
- α:=β;
-where the left side α is a condition statement, and the right side β is an action to be performed over α.
-D-rules (disambiguation rules) follow a slightly different formalism:
- α=P;
-where the left side α is a statement and the right side P is an integer from 0 to 255 that indicates the probability of occurrence of α.