Documentation

bestMatch query string will return Nothing if query is not a subsequence of string. Otherwise, it will return the "best" way to line up the characters in query with the characters in string. Lower-case characters in the query are assumed to be case-insensitive, and upper-case characters are assumed to be case-sensitive.

For example:

> bestMatch "ff" "FuzzyFind"
Just (Alignment {score = 25, result = Result {[Match "F", Gap "uzzy", Match "F", Gap "ind"]}})

The score indicates how "good" the match is. Better matches have higher scores. There's no maximum score (except for the upper limit of the Int datatype), but the lowest score is 0.

A substring from the query will generate a Match, and any characters from the input that don't result in a Match will generate a Gap. Concatenating all the Match and Gap results should yield the original input string.

Note that the matched characters in the input always occur in the same order as they do in the query pattern.

The algorithm prefers (and will generate higher scores for) the following kinds of matches:

1. Contiguous characters from the query string. For example, bestMatch "pp" will find the last two ps in "pickled pepper".
2. Characters at the beginnings of words. For example, bestMatch "pp" will find the first two Ps in "Peter Piper".
3. Characters at CamelCase humps. For example, bestMatch "bm" "BatMan" will score higher than bestMatch "bm" "Batman".
4. The algorithm strongly prefers the first character of the query pattern to be at the beginning of a word or CamelHump. For example, bestMatch "mn" "Bat Man" will score higher than bestMatch "atn" "Batman".

All else being equal, matches that occur later in the input string are preferred.

Finds input strings that match all the given input patterns. For each input that matches, it returns one Alignment. The output is not sorted. ascending.

For example:

> import Data.Foldable
> traverse_ (putStrLn . ("\n" ++) . highlight) $ fuzzyFind ["dad", "mac", "dam"] ["red macadamia", "Madam Card"]

Madam Card
* *** ** *

red macadamia
  * *******

A version of fuzzyFind that searches on the given text field of the data.

An Alignment is a Score together with a Result. Better results have higher scores.

The base score given to a matching character

The base score given to a mismatched character

Bonus points given to characters matching at the beginning of words

Bonus points given to characters matching a hump of a CamelCase word. We subtract a point from the word boundary score, since a word boundary will incur a gap penalty.

Double any bonus points for matching the first pattern of the character. This way we strongly prefer starting the match at the beginning of a word.

We prefer consecutive runs of matched characters in the pattern, so we impose a penalty for any gaps, which is added to the size of the gap.

We give a bonus to consecutive matching characters. A number about the same as the boundary bonus will prefer runs of consecutive characters vs finding acronyms.

Renders an Alignment as a pair of lines with "*" on the lower line indicating the location of pattern matches. highlight' :: Alignment -> Text highlight' (Alignment s (Result segments)) = foldMap prettySegment segments <> "n" <> foldMap showGaps segments where prettySegment (Gap xs) = xs prettySegment (Match xs) = xs showGaps (Gap xs) = Text.pack $ replicate (Text.length xs) ' ' showGaps (Match xs) = Text.pack $ replicate (Text.length xs) *

A highly configurable version of bestMatch.

Concatenating all the ResultSegments should yield the original input string.