Writing support

[bongodb.git] / src / bongodb.scm

diff --git a/src/bongodb.scm b/src/bongodb.scm
index 6fc16fe0fcfababa251b2e7686263640e2a2cd18..3e5dc680c115c49e5fa79f00eca1661e9952da90 100644 (file)
--- a/src/bongodb.scm
+++ b/src/bongodb.scm
@@ -25,9 +25,12 @@
            count
            insert
            find
+           update
            $eq
            $exists
-           $not))
+           $not
+           $and
+           $set))
 
 
 ;;; Collection Definition
@@ -78,26 +81,40 @@
               (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"
+  (map vhash->alist (inner-find col filter)))
+
+(define (inner-find col filter)
   "Query the collection and return the documents that match with filter"
   (let ((table (get-table col)))
     (vhash-fold
      (lambda (key document result)
        (cond ((match-document? document filter)
-             (cons (vhash->alist document) result))
+             (cons document result))
             (else
              result)))
      '()
      table)))
 
 (define (match-document? document filter)
-  "Try to match the given document with a list of conditions"
-  (cond ((null? filter)
+  "Try to match the given document with a given filter"
+  (cond ((equal? filter #t)
         #t)
        (else
-        (and
-         ((car filter) document)
-         (match-document? document (cdr filter))))))
+        (filter document))))
+
+(define (update col filter . changes)
+  "Update selected documents using the given filter"
+  (let ((documents (inner-find col filter)))
+    (apply insert (cons col (map (lambda (doc) (update-document doc changes)) documents)))))
+
+(define (update-document document changes)
+  "Update a document with the appropiate changes"
+  (cond ((null? changes)
+        document)
+       (else
+        (update-document ((car changes) document) (cdr changes)))))
 
 
 ;;; Queries
@@ -108,17 +125,29 @@
       (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))))
 
+(define-syntax $and
+  (syntax-rules ()
+    ((_ expr ...)
+     (lambda (document)
+       (and (expr document)
+           ...)))))
+
+
+;;; Updates
+
+(define ($set field value)
+  (lambda (document)
+    (vhash-cons field value document)))
+
             
 ;;; Tools