Simple query API question

[Preston Price]

This should be a pretty easy question to answer but I haven't been  
able to figure out how to do this with the API.

I want to search two fields in my index; field 1 is and ID, field 2 is  
a date of the form yyyymmdd.
Now I can write a query string by hand to do a search like this on  
both fields: "field1:(x or y or z) AND field2:[20080400 TO 20080500]"
But I don't see how to generate an equivalent query using the API.
Thanks in advance!

Preston Price
[EMAIL PROTECTED]