Parse Nodes¶

There are five types of nodes in E-HowNet expression — Entity, Reference, Placeholder, Feature, Function, and Subject.

Inheritance diagram of ehn.parse.node.base.EhnParseEntityBase, ehn.parse.node.base.EhnParseReferenceBase, ehn.parse.node.base.EhnParsePlaceholderBase, ehn.parse.node.base.EhnParseFeatureBase, ehn.parse.node.base.EhnParseFunctionBase, ehn.parse.node.base.EhnParseSubjectBase

Inheritance diagram of ehn.parse.node.entity, ehn.parse.node.reference, ehn.parse.node.placeholder, ehn.parse.node.feature, ehn.parse.node.other

Node Prototype¶

class EhnParseNode

The prototype of E-HowNet parsing nodes.

head: str¶: The head of this node.

get_features(key=None)¶

Get the features (or [] if not exists).

If key is set, returns only the features with feature.head==key.

get_arguments()¶: Get the arguments (or [] if not exists).

get_value()¶: Get the value (or None if not exists).

get_function()¶: Get the function (or None if not exists).

get_anchor()¶: Get the anchor (or None if not exists).

get_coindex()¶: Get the coindex key (the head of the anchor, the head of reference nodes, or None otherwise).

children()¶: Yields all direct child nodes of this node.

descendant()¶: Yields all descendant nodes (including self) of this node.

dumps()¶: Converts to text representation.

tree() → ehn.parse.node.base.EhnParseTree¶

Generates a tree representation of this node and all its descendant nodes.

One may use node.tree().show() to show a pretty tree representation.

Entity-Like Nodes¶

Entity¶

class EhnParseEntityBase

The base class of E-HowNet parsing entity nodes.

Subclasses:

EhnParseNormalEntity A normal entity. Can be an anchor.

EhnParseFunctionEntity An entity with function head. Can be an anchor.

EhnParseNameEntity A name entity.

EhnParseNumberEntity A number entity.

property features¶: A list of Features.

Reference¶

class EhnParseReferenceBase

The base class of E-HowNet parsing reference nodes.

Subclasses:

EhnParseCoindexReference An entity refers to an anchor entity.

EhnParseSubjectReference An entity refers to the unmentioned subject entity (EhnParseSubject in feature-based expressions.)

EhnParseTildeReference An entity refers to the root entity.

Placeholder¶

class EhnParsePlaceholderBase

The base class of E-HowNet parsing restriction nodes.

Subclasses:

EhnParseRestrictionPlaceholder. Can be an anchor.

EhnParseAnyPlaceholder A placeholder without restriction.

property value¶: Must be an Entity (for EhnParseRestrictionPlaceholder) or None (for EhnParseAnyPlaceholder).

Non-Entity-Like Nodes¶

Feature¶

class EhnParseFeatureBase

The base class of E-HowNet parsing feature nodes.

Subclasses:

EhnParseNormalFeature A normal feature.

EhnParseFunctionFeature An feature with function head.

property value¶: Can be a Entity-Like Node.

Function¶

class EhnParseFunctionBase

The base class of E-HowNet parsing function nodes.

Subclasses:

EhnParseFunction.

property arguments¶: A list of Entity-Like Nodes.

Subject¶

class EhnParseSubjectBase

The base class of E-HowNet parsing unmentioned subject nodes. Works similar to entities but is not an entity. Used only in feature-based expressions.

Subclasses:

EhnParseSubject. Always an anchor of x?.

property features¶: A list of Features.

Partial Nodes¶

Function Head¶

class EhnParseFunctionHead

The base class of nodes with a function as its head.

Note that the attribute obj.head of this object obj returns obj.function.head.

Subclasses:

EhnParseFunctionEntity

EhnParseFunctionFeature

property function¶: Must be a Function.

Anchor Body¶

class EhnParseAnchorBody

The base class of anchor nodes.

Subclasses:

EhnParseNormalEntity

EhnParseFunctionEntity

EhnParseRestrictionPlaceholder

EhnParseSubject

property anchor¶: The Anchor.

Anchor¶

class EhnParseAnchor

The coindex target.

head: str¶: The coindex of this anchor.