collection?
count
insert
- find))
+ find
+ $eq
+ $exists
+ $not))
;;; Collection Definition
(apply insert (cons newcol (cdr documents)))
(values rescol (cons docid docids)))))))
-(define (find col filter)
+(define (find col . filter)
"Query the collection and return the documents that match with filter"
(let ((table (get-table col)))
(vhash-fold
#t)
(else
(and
- (equal? (vhash-assoc (caar filter) document) (car filter))
+ ((car filter) document)
(match-document? document (cdr filter))))))
+;;; Queries
+
+(define ($eq field value)
+ (lambda (document)
+ (let ((stored (vhash-assoc field document)))
+ (and stored
+ (equal? (cdr stored) value)))))
+
+
+(define ($exists field)
+ (lambda (document)
+ (and (vhash-assoc field document)
+ #t)))
+
+
+(define ($not expr)
+ (lambda (document)
+ (not (expr document))))
+
+
;;; Tools
(define (vhash->alist vhash)