Class EarleySpan

Represents a collection of ambiguous completed states with the same left-hand side and span.

Inheritance

object

EarleySpan

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: EarleyParser

Assembly: EarleyParser.dll

Syntax

public class EarleySpan

Remarks

This class manages a list of completed Earley states (reductors) that share the same:

Left-hand side of the grammar rule
Start and end positions in the input

Constructors

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EarleySpan(EarleyState)

Initializes a new instance of the EarleySpan class.

Declaration

public EarleySpan(EarleyState state)

Parameters

Type	Name	Description
EarleyState	state	The initial completed state to add to this span.

Properties

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EndColumn

Gets or sets the column where this span ends in the parse chart.

Declaration

public EarleyColumn EndColumn { get; set; }

Property Value

Type	Description
EarleyColumn

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LeftHandSide

Gets or sets the left-hand side of the grammar rule shared by all states in this span.

Declaration

public string LeftHandSide { get; set; }

Property Value

Type	Description
string

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Reductors

Gets the list of completed states (reductors) in this span.

Declaration

public List<EarleyState> Reductors { get; }

Property Value

Type	Description
List<EarleyState>

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StartColumn

Gets the column where this span begins in the parse chart.

Declaration

public EarleyColumn StartColumn { get; }

Property Value

Type	Description
EarleyColumn

Methods

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Add(EarleyState)

Adds a completed state to this span.

Declaration

public void Add(EarleyState state)

Parameters

Type	Name	Description
EarleyState	state	The completed state to add.

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CountDerivations(Dictionary<EarleySpan, int>)

Counts the total number of distinct parse trees rooted at this span.

Declaration

public int CountDerivations(Dictionary<EarleySpan, int> visited)

Parameters

Type	Name	Description
Dictionary<EarleySpan, int>	visited	Dictionary to track visited spans and their derivation counts.

Returns

Type	Description
int	The total number of distinct parse trees.

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CountLengthsOfBasicTrees(Dictionary<EarleySpan, List<int>>, HashSet<string>, HashSet<string>, bool)

Counts the lengths of basic trees rooted at this span.

Declaration

public List<int> CountLengthsOfBasicTrees(Dictionary<EarleySpan, List<int>> visited, HashSet<string> encounteredNTs, HashSet<string> recursiveNTs, bool insideRecursion)

Parameters

Type	Name	Description
Dictionary<EarleySpan, List<int>>	visited	Dictionary to track visited spans and their tree lengths.
HashSet<string>	encounteredNTs	Set of non-terminals encountered in the current path.
HashSet<string>	recursiveNTs	Set of non-terminals known to be recursive.
bool	insideRecursion	Indicates whether we are already inside a recursive structure.

Returns

Type	Description
List<int>	List of lengths of basic trees. Returns [-1] for recursive structures.

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GetFormattedString(Grammar, Dictionary<EarleySpan, Color>, bool)

Gets formatted string representations of the parse tree.

Declaration

public List<StringBuilder> GetFormattedString(Grammar g, Dictionary<EarleySpan, Color> visited, bool onlyPartsOfSpeechSequences = false)

Parameters

Type	Name	Description
Grammar	g	The grammar used for parsing.
Dictionary<EarleySpan, Color>	visited	Dictionary to track visited spans and their colors for cycle detection.
bool	onlyPartsOfSpeechSequences	Whether to only include parts of speech in the output.

Returns

Type	Description
List<StringBuilder>	List of StringBuilder objects containing formatted string representations.

Remarks

The output can be either:

Bracketed representation of the subtree, e.g. (START (NP (PN John)) (VP (V0 cried)))
Parts of speech sequences, e.g. PN V0 (PN = proper noun)

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GetPOSRulesInEachDerivation(Grammar, Dictionary<EarleySpan, List<HashSet<Rule>>>, int)

Gets the parts of speech rules used in each derivation.

Declaration

public List<HashSet<Rule>> GetPOSRulesInEachDerivation(Grammar g, Dictionary<EarleySpan, List<HashSet<Rule>>> visited, int i)

Parameters

Type	Name	Description
Grammar	g	The grammar used for parsing.
Dictionary<EarleySpan, List<HashSet<Rule>>>	visited	Dictionary to track visited spans and their POS rules.
int	i	The index of the current derivation.

Returns

Type	Description
List<HashSet<Rule>>	List of sets of rules containing parts of speech.