Features

Features are used to describe a configuration. Four types of features are defined, Word Features, Syntactic Features, Distance Features and Configurational Features. These types are described below.

Usually a configuration is described through a collection of features. Such collections are defined in Feature Model files.

Word features

Words feature describe different attributes of the words present in the buffer or in the stack. They are composed of an address function identifying a particular word and an attribute function selecting a specific attribute of the word, such as its form, lemma, part of speech ...

Word features are represented as strings that are the concatenation of the address function and the attribute function. The feature s0f for example is the concatenation of the address function s0 and the attribute function f, it corresponds to the form of the word which is on the top of the stack.

The following address functions are defined:

• b0 the current word in the buffer
• b1 the word following b0
• b2 the word following b1
• b3 the word following b2
• bm1 the word preceding b0
• bm2 the word preceding b1
• bm3 the word preceding b2
• s0 the word on the top of the stack
• s1 the word below s0
• s2 the word below s1
• s3 the word below s2

The following attribute functions are defined:

• f the form the word
• l its lemma
• c its coarse part of speech
• p its part of speech
• m its morphological features
• r its syntactic function (r stands for role ?)
• g a binary feature indicating if the word already has a governor
• A to Z other attributes of the word that are present in the mcf file

Syntactic Features

• ldep_s0r label of the leftmost dependent of s0
• ldep_s0p pos of the leftmost dependent of s0
• rdep_s0r label of the rightmost dependent of s0
• rdep_s0p pos of the rightmost dependent of s0
• ldep_s1r label of the leftmost dependent of s1
• ldep_s1p pos of the leftmost dependent of s1
• rdep_s1r label of the rightmost dependent of s1
• rdep_s1p pos of the rightmost dependent of s1
• ndep_s0 number of dependents of s0

Distance Features

• dist_s0_b0 linear distance between s0 and b0

Configurational Features

• sh number of elements in the stack
• t1 code of the previous transition (the transition that led to the current configuration)
• t2 code of the transition preceding t1
• t3 code of the transition preceding t2
• t4 code of the transition preceding t3
• mvt0
• mvt1
• mvt2
• mvt3
• delta1
• delta2
• delta3