I'm disappointed by the deprecation and decay of features of DDG and Goog in recent years, it seems like the trend is toward dumbing-down.

It used to be that double-quoted strings meant "search for exactly this, not fuzzy searches". Now, DDG requires a plus sign in front of a double-quoted string. +"KS-19319ZJFT"

Also, way, way back, you could conduct elaborate boolean searches like (space equals implicit "and", so it's omitted):

    site:foo.com -site:docs.foo.com ((lemons "crab apples") or ((oranges beans) (cherries plums)))

Ideally, I'd like a syntax that looks like this:

    search = "( search ")"
           | "-" search
           | search ("and")? search
           | search "or" search
           | constraint
           | term

    term = quoted_term
         | simple_term

    quoted_term = '"'([^"\\]|'\\"')+'"'
                | "'"([^'\\]|"\\'")+"'"

    simple_term = [^'" ]+

    constraint = file_type_constraint
               | url_constraint
               | site_constraint
               | temporal_constraint

    file_type_constraint = "filetype:" (common_type|"*"?"."?[a-z0-9]+)
                         | "mimetype:" regex

    common_type = "video"|"photo"|"audio"|"email"|"web"|"document"|"text"

    url_constraint = "inurl:" regex
 
    site_constraint = "site:" regex

    time_constraint = "before:" date 
                    | "after:" date
                    | "within:" time

    /* "and," "or," and : prefixes should be case-insensitive and localizable */
    /* date, time and regex are "exercises for the reader" ;) */