Recently I needed to parse a fairly sophisticated search syntax for a project. I needed a pure XQuery solution, and MarkLogic's built-in search API wouldn't handle some of the syntax: nested groups, for example. So I wrote another one.
Here is a rough cut at the BNF
L ::= expr*
expr ::= group | infixExpr | term
group ::= prefixOp? '(' expr* ')'
prefixOp ::= "+" | "-" | "~" | "NOT"
infixExpr ::= (term | group) " " infixOp " " (term | group)
infixOp ::= "*" | "OR" | "|" | "AND" | "ANDNOT" | "NOTIN"
term ::= prefixOp? (field fieldOp)? (group | literal)
field ::= (letter | "_")+
fieldOp ::= [":" | "=" | ">" | ">=" | "<" | "<=" | "!" | "!="]
literal ::= (word | quoted_words) weight?
quoted_words ::= '"' word (" " word)* '"'
word ::= (letter | digit | "_")+
weight ::= ^digit+
number ::= digit+
letter ::= [A-Za-z]
digit ::= [0-9]
XQYSP takes a slightly different approach than the Search API
or the older lib-parser.xqy, both of which returned cts:query items.
Instead, XQYSP returns an abstract syntax tree (AST) as XML.
It is up to you, the caller, to transform that AST into a cts:query.
That is a little more work for you,
but adds a lot of flexibility at the same time.
Most of the tasks that used to go into lib-parser-custom.xqy
can now be implemented without changing the parser itself.
To make it easier to get started, though,
there is some sample XQuery to generate a query from an AST in
query-eval.xqy
and there is a test case in
xqysp.xml.
The query-eval.xqy code is provided as a simple example:
copy and modify it as needed for your application.
If the syntax isn't exactly what you need, this could make a nice template for your own search parser. Patches are also welcome.
The test cases use XQUT. If you find problems, please provide a test case.
Copyright (c) 2011-2014 Michael Blakeley. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
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