dfilter: Allow testing for nonzero function result

Allow functions to be tested for "existence". This is in fact
not an existence test but a truthiness test for the function
return value.

1 files changed, 8 insertions, 0 deletions

diff --git a/doc/release-notes.adoc b/doc/release-notes.adoc
index adcb9bd8e9..3c00a44016 100644
--- a/doc/release-notes.adoc
+++ b/doc/release-notes.adoc
@@ -51,6 +51,14 @@ The following features are new (or have been significantly updated) since versio
 
   ** The keyword "bitand" can be used as an alternative syntax for the bitwise-and operator.
 
+  ** Functions alone can now be used as an entire logical expression.
+     The result of the expression is the truthiness of the function return
+     value (or of all values if more than one). This is useful for example to write
+     "len(something)" instead of "len(something) != 0". Even more so if a function
+     returns itself a boolean value, it is now possible to write
+     "bool_test(some.field)" instead of having to write "bool_test(some.field) == True"
+     (both forms are now valid).
+
 //=== Removed Features and Support
 
 // === Removed Dissectors