mastodon/app/lib/search_query_parser.rb

# frozen_string_literal: true

class SearchQueryParser < Parslet::Parser
  rule(:term)     { match('[^\s":]').repeat(1).as(:term) }
  rule(:quote)    { str('"') }
  rule(:colon)    { str(':') }
  rule(:space)    { match('\s').repeat(1) }
  rule(:operator) { (str('+') | str('-')).as(:operator) }
  rule(:prefix)   { (term >> colon).as(:prefix) }
  rule(:phrase)   { (quote >> (term >> space.maybe).repeat >> quote).as(:phrase) }
  rule(:clause)   { (prefix.maybe >> operator.maybe >> (phrase | term)).as(:clause) }
  rule(:query)    { (clause >> space.maybe).repeat.as(:query) }
  root(:query)
end