Grammar Specs

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The following Grammar Specs are used for writing rules for the UNDL Foundation tools (IAN,EUGENE,SEAN,NORMA,etc.).

Basic symbols

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

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.
Software