Package jazzparser :: Package data :: Module trees

Module trees

Building derivation trees from annotated chord sequences.

Trees are minimally represented in the database. Each chord may define certain pieces of additional tree information which influence the way its tree structure is built.

A default tree structure is defined by a left-to-right parsing algorithm, which applies rules as it may in a particular order. The algorithm does not parse properly, but uses only the slash direction information to decide what rule to apply. Essentially this results in trees in which slash categories are always composed as soon as possible and then applied. Consecutive atomic categories must unambiguously be combined by continuation. Coordination will never be used by the default trees. A minimal amount of information (the end of each coordinated constituent) can be specified on the chords to prompt the tree to use coordination. The first constituent is always as long as possible (which is a reasonable arbitrary canonical tree).

Note that this should not operate directly on sequences read from the database, but on their mirrors (see jazzparser.data.db_mirrors), since this allows it potentially to be used independently of the database.

Author: Mark Granroth-Wilding <mark.granroth-wilding@ed.ac.uk>

Classes

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GeneralizedCategory
Partially represents a CCG category in a simple way.

SlashCategory

AtomicCategory

UnknownCategory
The categories of some chords are unknown and not specified in the annotation.

StackMarker
Special type to place markers among the categories in the stack.

CoordinationMiddleMarker
Marks the end of the first part of a coordination.

SyntacticTreeNode
Superclass of nodes in syntactic trees.

SyntacticNonTerminal
An internal node in a syntactic tree.

SyntacticTerminal
A terminal node (leaf) in a syntactic tree.

SyntacticTreeRoot
The root of a syntactic tree.

TreeBuildError

Functions

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attach_tree(cat, inputs, rule)
Attach a non-terminal tree to a category on the basis of the inputs from which it was built.

source code

_comp(dir, stack)
Generic composition (use compf or compb).

source code

compf(stack)
Forward composition

source code

compb(stack)
Backward composition

source code

appf(stack)
Forward application

source code

appb(stack)
Backward application

source code

cont(stack)
Tonic continuation

source code

coord(stack)
Cadence coordination

source code

generalize_category(category, formalism)
Builds a simple GeneralizedCategory from a real grammatical category as represented in the parser (see the Music Keyspan formalism).

source code

build_tree_for_sequence(sequence, debug_stack=False, grammar=None, logger=None)
Run through the motions of parsing the sequence in order to build its tree structure.

source code

tree_to_nltk(intree)
Given a syntactic tree using the SyntacticTreeNode classes, produces an NLTK tree.

source code

Variables

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__package__ = 'jazzparser.data'

Function Details

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build_tree_for_sequence(sequence, debug_stack=False, grammar=None, logger=None)

source code

Run through the motions of parsing the sequence in order to build its tree structure. Most of the structure is implicit in the lexical categories. Additional information is given in the TreeInfo model, associated with chords.

tree_to_nltk(intree)

source code

Given a syntactic tree using the SyntacticTreeNode classes, produces an NLTK tree. This is useful, for example, to display a tree: tree.draw(). You need NLTK installed to be able to do this.