lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Brian Goetz <>
Subject Re: Rationale for having boolean operators as ALL CAPS
Date Thu, 18 Apr 2002 23:20:53 GMT

>Can someone tell me the rationale for having the boolean operator only work
>if they are all caps?

I can, since I was the one who made this decision.

Most queries are entered in lower or mixed case.  Treating 'and' as a 
boolean operator has two deleterious effects:
  - it removes 'and' from the spaces of tokens that can be part of a search 
string, and even though most users will probably include 'and' in their 
stop-list filter, not all will;
  - An overriding goal of the query parser syntax design was to not 
introduce features that are likely to catch unsophisticated users.  Using 
lower case 'and' and 'or' as search modifiers could confuse users who are 
not aware that one can specify anything but a series of words.  The other 
syntax (&&, [], ~) were deliberately chosen to be unlikely to occur in 
typical query texts.

In my mind, the only alternative was not supporting AND at all and forcing 
users to use the symbols.  So instead of thinking about it as "'and' 
doesn't work", think about it as "Isn't it nice that 'AND' is a convenient 
synonym for '&&'".

Brian Goetz
Quiotix Corporation           Tel: 650-843-1300            Fax: 650-324-8032

To unsubscribe, e-mail:   <>
For additional commands, e-mail: <>

View raw message