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README.txt
Description of Surround: Surround consists of operators (uppercase/lowercase): AND/OR/NOT/nW/nN/() as infix and AND/OR/nW/nN as prefix. Distance operators W and N have default n=1, max 99. Implemented as SpanQuery with slop = (n - 1). An example prefix form is: 20n(aa*, bb*, cc*) The name Surround was chosen because of this prefix form and because it uses the newly introduced span queries to implement the proximity operators. The names of the operators and the prefix and suffix forms have been borrowed from various other query languages described on the internet. Query terms from the Lucene standard query parser: field:termtext ^ boost * internal and suffix truncation ? one character Some examples: aa aa and bb aa and bb or cc same effect as: (aa and bb) or cc aa NOT bb NOT cc same effect as: (aa NOT bb) NOT cc and(aa,bb,cc) aa and bb and cc 99w(aa,bb,cc) ordered span query with slop 98 99n(aa,bb,cc) unordered span query with slop 98 20n(aa*,bb*) 3w(a?a or bb?, cc*) title: text: aa title : text : aa or bb title:text: aa not bb title:aa not text:bb cc 3w dd infix: dual. cc N dd N ee same effect as: (cc N dd) N ee text: aa 3d bb For examples on using the Surround language, see the test packages. Development status Not tested: multiple fields, internally mapped to OR queries, not compared to Lucene's MultipleFieldQuery. * suffix truncation is implemented very similar to Lucene's PrefixQuery. Wildcards (? and internal *) are implemented with regular expressions to allow further variations. A reimplementation using WildCardTermEnum (correct name?) should be no problem. Warnings about missing terms are sent to System.out, this might be replaced by another stream, and tested for in the tests. BooleanQueryTst.TestCollector uses a results checking method that should be replaced by the checking method from Lucene's TestBasics.java.