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const (
	// Levenshtein computes the Levenshtein distance between two
	// strings. The returned value - distance - is the number of insertions,
	// deletions, and substitutions it takes to transform one
	// string (s1) into another (s2). Each step in the transformation "costs"
	// one distance point.
	Levenshtein DistanceCalculator = iota

	// DamerauLevenshtein computes the Damerau-Levenshtein distance between two
	// strings. The returned value - distance - is the number of insertions,
	// deletions, substitutions, and transpositions it takes to transform one
	// string (s1) into another (s2). Each step in the transformation "costs"
	// one distance point. It is similar to the Optimal String Alignment,
	// algorithm, but is more complex because it allows multiple edits on
	// substrings.
	DamerauLevenshtein

	// Hamming computes the Hamming distance between two equal-length strings.
	// This is the number of times the two strings differ between characters at
	// the same index. This implementation is based off of the algorithm
	// description found at http://en.wikipedia.org/wiki/Hamming_distance.
	Hamming

	// Jaro computes the Jaro edit distance between two strings. It represents
	// this with a float64 between 0 and 1 inclusive, with 0 indicating the two
	// strings are not at all similar and 1 indicating the two strings are exact
	// matches.
	//
	// See http://en.wikipedia.org/wiki/Jaro%E2%80%93Winkler_distance for a
	// full description.
	Jaro

	// JaroWinkler computes the Jaro-Winkler edit distance between two strings.
	// This is a modification of the Jaro algorithm that gives additional weight
	// to prefix matches.
	JaroWinkler

	// OSA computes the Optimal String Alignment distance between two
	// strings. The returned value - distance - is the number of insertions,
	// deletions, substitutions, and transpositions it takes to transform one
	// string (s1) into another (s2). Each step in the transformation "costs"
	// one distance point. It is similar to Damerau-Levenshtein, but is simpler
	// because it does not allow multiple edits on any substring.
	Osa

	// SmithWaterman computes the Smith-Waterman local sequence alignment for the
	// two input strings. This was originally designed to find similar regions in
	// strings representing DNA or protein sequences.
	SmithWaterman
)

const (
	AndOperator      Operator = "AND"
	BoostOperator    Operator = "^"
	FieldOperator    Operator = ":"
	FuzzyOperator    Operator = "~"
	NilOperator      Operator = ""
	NotOperator      Operator = "NOT"
	OrOperator       Operator = "OR"
	WildCardOperator Operator = "*"
)

const (
	// DoubleMetaphone computes the Double-Metaphone value of the input string.
	// This value is a phonetic representation of how the string sounds, with
	// affordances for many different language dialects. It was originally
	// developed by Lawrence Phillips in the 1990s.
	//
	// More information about this algorithm can be found on Wikipedia at
	// http://en.wikipedia.org/wiki/Metaphone.
	DoubleMetaphone PhoneticPreprocessor = iota

	// NYSIIS computes the NYSIIS phonetic encoding of the input string. It is a
	// modification of the traditional Soundex algorithm.
	Nysiis

	// Phonex computes the Phonex phonetic encoding of the input string. Phonex is
	// a modification of the venerable Soundex algorithm. It accounts for a few
	// more letter combinations to improve accuracy on some data sets.
	//
	// This implementation is based off of the original C implementation by the
	// creator - A. J. Lait - as found in his research paper entitled "An
	// Assessment of Name Matching Algorithms."
	Phonex

	// Soundex computes the Soundex phonetic representation of the input string. It
	// attempts to encode homophones with the same characters. More information can
	// be found at http://en.wikipedia.org/wiki/Soundex.
	Soundex
)

const (
	BoolQuery QueryType = iota
	FuzzyQuery
	PhraseQuery
	TermQuery
	WildCardQuery
)