Grammar Specs
From UNL Wiki
The following Grammar Specs are used for writing rules for the UNDL Foundation tools (IAN, EUGENE, SEAN, NORMA, etc.).
Basic Symbols
| Symbol | Definition | Example |
|---|---|---|
| ( ) | node | (%a) |
| " " | string | "went" |
| [ ] | natural language entry (headword) | [go] |
| [[ ]] | UW | [[to go(icl>to move)]] |
| // | regular expression | /a{2,3}/ = aa,aaa |
| rel(x;y) | relation | agt(kill;Peter) |
| ^ | not | ^a = not a |
| { | } | or | {a|b} = a or b |
| % | index for nodes, attributes and values | %x |
| : | scope ID | :01 |
| # | index for sub-NLWs | #01 |
| = | attribute-value assignment | POS=NOU |
| ! | rule trigger | !PLR |
| & | merge operator | %x&%y |
| ? | dictionary lookup operator | ?[a] |
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.
- 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.
