X-Git-Url: https://git.jsancho.org/?p=bongodb.git;a=blobdiff_plain;f=src%2Fbongodb.scm;h=6fc16fe0fcfababa251b2e7686263640e2a2cd18;hp=e4df14bde9e1699503e91b4b9d6b9883446ba0b1;hb=07eed7138a1b4aecb9d8ae0926ba22dc82ebe94e;hpb=0fe9f925e00b6899f3b685082ed9b3374933c527

diff --git a/src/bongodb.scm b/src/bongodb.scm
index e4df14b..6fc16fe 100644
--- a/src/bongodb.scm
+++ b/src/bongodb.scm
@@ -24,7 +24,10 @@
 	    collection?
 	    count
 	    insert
-	    find))
+	    find
+	    $eq
+	    $exists
+	    $not))
 
 
 ;;; Collection Definition
@@ -75,7 +78,7 @@
 	       (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
@@ -93,10 +96,30 @@
 	 #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)