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vendor/github.com/bcampbell/qs/syntax.md

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+# Query String Syntax
+
+## Basics
+
+Single words are treated as simple terms. The results will include
+documents containing those terms, eg:
+
+    embiggen
+    cromulent
+
+Terms are separated by spaces, so:
+
+    navel orange
+
+Will match both documents containing "navel" and documents containing "orange",
+which is probably not what was intended. The user was probably looking for
+documents about "navel oranges" rather than those about "orange navels".
+
+To search for phrases - multiple words, matched in order - enclose them in double quotes.
+
+For example:
+
+    "navel orange"
+
+## Boolean Operators
+
+### `OR`
+
+The `OR` operator returns documents matched by terms on either side of it.
+It is the default operator, meaning that the following two queries are
+considered to be equivalent:
+
+    orange OR "navel orange"
+    orange "navel orange"
+
+Note that the query parser can be set up to use `AND` as the default operator instead of `OR`.
+
+### `AND`
+
+'`AND`' returns documents which match the terms on *both* sides.
+
+    orange AND citrus
+
+### `+`
+
+'`+`' is the 'required' operator. A term prefixed with '`+`' must exist in matching
+documents.
+
+For example, to return documents definitely containing "orange" and maybe also
+containing "fruit":
+
+    fruit +orange
+
+
+### `NOT`
+
+`NOT` excludes documents that match the following term.
+
+For example, to match documents containing "orange" but not "paint":
+
+    orange NOT paint
+
+
+### `-`
+
+Prefixing a term with '`-`' will "prohibit" it.
+
+For example, to match documents containing "orange" but not "paint":
+
+    orange -paint
+
+
+### Precedence
+
+`-`, `+` and `NOT` take precedence over `AND`, which takes precedence over `OR`.
+
+For example,
+
+    lemon OR orange AND citrus
+
+is treated as:
+
+    lemon OR (orange AND citrus)
+
+
+
+## Field Scoping
+
+You can control which fields are matched by prefixing the name of a field separated by a colon.
+
+Examples:
+
+    genus:citrus
+    headline:"How to Make the Perfect Negroni"
+    tags:(fruit OR paint)
+
+If no field is specified, the default `_all` is used, unless overridden in the index mapping.
+
+
+## Grouping
+
+Parentheses can be used to group sub queries.
+For example:
+
+    (shaddock OR pomelo OR pamplemousse) AND (family:rutaceae AND NOT genus:fortunella) AND colour:(greenish OR yellowish)
+
+## Wildcards
+
+Within an individual term, partial matches can be described using wildcard characters:
+
+`?` to match any single character
+
+`*` To match and sequence of zero or more characters
+
+For example:
+
+     qu?ck bro*
+
+
+## Fuzziness
+
+A fuzzy query is a term query that matches terms within a given [Levenshtein distance](https://en.wikipedia.org/wiki/Levenshtein_distance).
+The edit distance is the number of single-character edits (insertions, deletions or substitutions) allowed.
+
+To specify a fuzzy query, use the tilde sign (`~`), optionally followed by the edit distance you'll accept.
+
+
+For example,
+
+    colour~1
+
+to match "`colour`" or "`color`" (or "`zolour`" or "`colours`"... but not "`colors`", as the `~1` allows only a single character change).
+
+If no number is specified, the default value is 1, so the following are equivalent:
+
+    wibble~
+    wibble~1
+
+
+
+## Boosting
+
+Boosting a term doesn't affect the set of matching documents, but it does
+indicate that that term should be assigned greater importance when the
+results are being scored by relevance.
+
+To boost a term, you use the boost operator '`^`' followed by a number
+indicating the relative importance of the term.
+
+For example, in the following query, "grapefruit" should be considered twice
+as important as "lime":
+
+    grapefruit^2 lime
+
+You can boost more complex sub queries:
+
+    (grapefruit OR orange)^2 "navel orange"^4 genus:citrus
+
+
+
+## Ranges
+
+Inclusive ranges can be described with square braces and `TO`, eg:
+
+    num:[1 TO 5]
+    date:[2010-01-01 TO 2010-01-31]
+
+Dates must be in `YYYY-MM-DD` form.
+
+Exclusive ranges are supported using curly braces. So, these are equivalent:
+
+    score:{0 TO 10}
+    score:[1 TO 9]
+
+
+
+You can mix inclusive and exclusive endpoints, eg:
+
+    pubdate:[2010-01-01 TO 2011-01-01}
+    shoesize:{0 TO 16]
+    byte:[0 TO 256}
+
+You can have open ranges by leaving off either endpoint:
+
+    pubdate:[2000-01-01 TO ]
+    temp:[TO 100}
+
+
+NOTE: ranges currently work only on numeric and date fields.
+
+
+## Relational Operators
+
+You can perform numeric comparisons using the `>`, `>=`, `<`, and `<=` operators.
+These are equivalent to using the above range syntax with unbounded ranges.
+
+For example:
+
+    score:>=100
+    score:[ TO 100]
+
+