object

`string_distance(Representation)`

Representation - String representation. Valid values are atom, codes, and chars.

String distance predicates.

Availability:

logtalk_load(string_distance(loader))

Author: Paulo Moura
Version: 1:0:0
Date: 2026-02-05

Compilation flags:

static, context_switching_calls

Uses:

integer
list
set

Remarks:

(none)

Inherited public predicates:

(none)

Public predicates 

`levenshtein/3`

Computes the Levenshtein distance between two strings.

Compilation flags:

static

Template:

levenshtein(String1,String2,Distance)

String1 - First input string.
String2 - Second input string.
Distance - Minimum number of single-character edits (insertions, deletions, substitutions) to transform String1 into String2.

Mode and number of proofs:

levenshtein(+text,+text,-integer) - one

`damerau_levenshtein/3`

Computes the Damerau-Levenshtein distance between two strings.

Compilation flags:

static

Template:

damerau_levenshtein(String1,String2,Distance)

String1 - First input string.
String2 - Second input string.
Distance - Minimum number of edits (insertions, deletions, substitutions, and adjacent transpositions) to transform String1 into String2.

Mode and number of proofs:

damerau_levenshtein(+text,+text,-integer) - one

`hamming/3`

Computes the Hamming distance between two strings of equal length. Fails if the strings differ in length.

Compilation flags:

static

Template:

hamming(String1,String2,Distance)

String1 - First input string.
String2 - Second input string (must have the same length as String1).
Distance - Number of positions at which the corresponding characters differ.

Mode and number of proofs:

hamming(+text,+text,-integer) - zero_or_one

`jaro/3`

Computes the Jaro similarity score between two strings.

Compilation flags:

static

Template:

jaro(String1,String2,Similarity)

String1 - First input string.
String2 - Second input string.
Similarity - A value between 0.0 (completely different) and 1.0 (identical), based on matching characters and transpositions.

Mode and number of proofs:

jaro(+text,+text,-float) - one

`jaro_winkler/3`

Computes the Jaro-Winkler similarity score between two strings.

Compilation flags:

static

Template:

jaro_winkler(String1,String2,Similarity)

String1 - First input string.
String2 - Second input string.
Similarity - A value between 0.0 and 1.0. Extends Jaro similarity with a prefix bonus: strings sharing a common prefix are scored higher.

Mode and number of proofs:

jaro_winkler(+text,+text,-float) - one

`edit_similarity/3`

Computes the edit similarity score between two strings using Levenshtein distance.

Compilation flags:

static

Template:

edit_similarity(String1,String2,Similarity)

String1 - First input string.
String2 - Second input string.
Similarity - A value between 0.0 and 1.0 computed as 1 - (edit distance / max length of the two strings).

Mode and number of proofs:

edit_similarity(+text,+text,-float) - one

`edit_similarity/4`

Computes the edit similarity score between two strings using the given algorithm.

Compilation flags:

static

Template:

edit_similarity(Algorithm,String1,String2,Similarity)

Algorithm - Edit distance algorithm. Valid values are levenshtein, damerau_levenshtein, hamming, and longest_common_subsequence.
String1 - First input string.
String2 - Second input string.
Similarity - A value between 0.0 and 1.0 computed as 1 - (edit distance / max length of the two strings).

Mode and number of proofs:

edit_similarity(+atom,+text,+text,-float) - one

`longest_common_subsequence_length/3`

Computes the length of the Longest Common Subsequence between two strings.

Compilation flags:

static

Template:

longest_common_subsequence_length(String1,String2,Length)

String1 - First input string.
String2 - Second input string.
Length - Length of the longest subsequence common to both strings (characters need not be contiguous).

Mode and number of proofs:

longest_common_subsequence_length(+text,+text,-integer) - one

`longest_common_subsequence/3`

Computes the Longest Common Subsequence itself between two strings.

Compilation flags:

static

Template:

longest_common_subsequence(String1,String2,Subsequence)

String1 - First input string.
String2 - Second input string.
Subsequence - The longest subsequence common to both strings (characters need not be contiguous). If multiple exist, one is returned nondeterministically.

Mode and number of proofs:

longest_common_subsequence(+text,+text,-atom) - one

`longest_common_substring/3`

Computes the longest contiguous common substring between two strings.

Compilation flags:

static

Template:

longest_common_substring(String1,String2,Substring)

String1 - First input string.
String2 - Second input string.
Substring - The longest contiguous substring shared by both strings. If multiple exist, one is returned nondeterministically.

Mode and number of proofs:

longest_common_substring(+text,+text,-atom) - one

`cosine_similarity/3`

Computes the cosine similarity between two token lists.

Compilation flags:

static

Template:

cosine_similarity(Tokens1,Tokens2,Similarity)

Tokens1 - First token list (e.g., list of words or character n-grams).
Tokens2 - Second token list.
Similarity - A value between 0.0 and 1.0 representing the cosine of the angle between the two token vectors.

Mode and number of proofs:

cosine_similarity(+list(text),+list(text),-float) - one

`jaccard_index/3`

Computes the Jaccard index (similarity) between two token lists.

Compilation flags:

static

Template:

jaccard_index(Tokens1,Tokens2,Index)

Tokens1 - First token list (e.g., list of words or character n-grams).
Tokens2 - Second token list.
Index - A value between 0.0 (no overlap) and 1.0 (identical sets), computed as |intersection| / |union|.

Mode and number of proofs:

jaccard_index(+list(text),+list(text),-float) - one

`soundex/2`

Computes the Soundex phonetic encoding for a string.

Compilation flags:

static

Template:

soundex(String,Encoding)

String - Input string (typically a name).

Encoding - A four-character Soundex code representing the phonetic encoding.

Mode and number of proofs:

soundex(+text,-atom) - one

`soundex_match/2`

Succeeds if two strings share the same Soundex code.

Compilation flags:

static

Template:

soundex_match(String1,String2)

String1 - First input string.

String2 - Second input string.

Mode and number of proofs:

soundex_match(+text,+text) - one

`metaphone/2`

Computes the Metaphone phonetic key for a string.

Compilation flags:

static

Template:

metaphone(String,Encoding)

String - Input string (typically a name).

Encoding - The Metaphone phonetic encoding, a more accurate phonetic encoding than Soundex.

Mode and number of proofs:

metaphone(+text,-atom) - one

`metaphone_match/2`

Succeeds if two strings share the same Metaphone key.

Compilation flags:

static

Template:

metaphone_match(String1,String2)

String1 - First input string.

String2 - Second input string.

Mode and number of proofs:

metaphone_match(+text,+text) - one

`double_metaphone/3`

Computes the Double Metaphone encoding of a text, returning both primary and alternative encodings.

Compilation flags:

static

Template:

double_metaphone(Text,Primary,Alternative)

Text - Input string (typically a name).
Primary - Primary Double Metaphone encoding.
Alternative - Alternative Double Metaphone encoding.

Mode and number of proofs:

double_metaphone(+text,-atom,-atom) - one

`double_metaphone_match/2`

Succeeds if the Double Metaphone encodings of two texts match (either primary or alternative encodings).

Compilation flags:

static

Template:

double_metaphone_match(String1,String2)

String1 - First input string.

String2 - Second input string.

Mode and number of proofs:

double_metaphone_match(+text,+text) - zero_or_one

Protected predicates 

(no local declarations; see entity ancestors if any)

Private predicates 

(no local declarations; see entity ancestors if any)

Operators 

(none)

string_distance(Representation)

`string_distance(Representation)`