View source for N-rule

Normalization rules are used to prepare the natural language input for automatic processing. They constitute the preprocessing module that applies over the input as a string and runs prior to the [[tokenization]]. The set of n-rules forms the '''Normalization Grammar''', or '''N-Grammar'''.

== Syntax ==
Normalization Rules follow the very general formalism
 α:=β;
where the left side α is a condition statement, and the right side β is an action to be performed over α.

== Type of Normalization Rules ==
Normalization rules are used only to replace strings in the natural language input text.

{|cellpadding="5" border="1" align="center"
|+LL rules
!ACTION
!RULE
!DESCRIPTION
|-
|REPLACE
|(%x):=(%y);
|All the instances of the node %x will be replaced by the node %y
|-
|}
<div align="center">Where %x and %y are nodes.</div>


== Roles of Normalization Rules ==
Normalization roles have two roles:
*to normalize the input text (to replace abbreviations by their extend forms, to extend contractions, etc.)
*to segment the natural language text into sentences (i.e., to create the tags <SHEAD> (beginning of a sentence), <STAIL> (end of a sentence), <CHEAD> (beginning of a scope) and <CTAIL> (end of a scope) inside the input text). These tags are used as sentence and clause boundaries, and define the units of processing of the Transformation and Disambiguation grammars.

== Examples of Normalization rules ==
*Segmentation
**("/.*\./",%x):=(%x)(+STAIL,%y); (creates an STAIL node after any sequence of characters followed by "." (/.*\./);
**("/\(/",%x):=(+CHEAD,%y)(%x); (creates an CHEAD node before the opening of a parentheses (/\(/);
*Normalization
**("an "):=("a "); ("an apple" > "a apple")
**("don't"):=("do not"); ("I don't see" > "I do not see")