Remove keys

properties.go

@@ -596,6 +596,22 @@ func (p *Properties) WriteComment(w io.Writer, prefix string, enc Encoding) (n i
 
 // ----------------------------------------------------------------------------
 
+// Delete removes the key and its comments
+// abides by the rules of the builtin delete()
+func (p *Properties) Delete(key string) () {
+	delete(p.m, key)
+	delete(p.c, key)
+	newKeys := []string{}
+	for _, k := range p.k {
+		if k != key {
+			newKeys = append(newKeys, key)
+		}
+	}
+	p.k = newKeys
+}
+
+// ----------------------------------------------------------------------------
+
 // check expands all values and returns an error if a circular reference or
 // a malformed expression was found.
 func (p *Properties) check() error {

properties_test.go

@@ -797,6 +797,32 @@ func (s *TestSuite) TestPanicOn32BitUintOverflow(c *C) {
 	c.Assert(func() { p.MustGetUint("max") }, PanicMatches, ".* out of range")
 }
 
+func (s *TestSuite) TestDeleteKey(c *C) {
+	input := "#comments should also be gone\nkey=to-be-deleted\nsecond=key"
+	p, err := parse(input)
+	c.Assert(err, IsNil)
+	c.Check(len(p.m), Equals, 2)
+	c.Check(len(p.c), Equals, 1)
+	c.Check(len(p.k), Equals, 2)
+	p.Delete("key")
+	c.Check(len(p.m), Equals, 1)
+	c.Check(len(p.c), Equals, 0)
+	c.Check(len(p.k), Equals, 1)
+}
+
+func (s *TestSuite) TestDeleteUnknownKey(c *C) {
+	input := "#comments should also be gone\nkey=to-be-deleted"
+	p, err := parse(input)
+	c.Assert(err, IsNil)
+	c.Check(len(p.m), Equals, 1)
+	c.Check(len(p.c), Equals, 1)
+	c.Check(len(p.k), Equals, 1)
+	p.Delete("wrong-key")
+	c.Check(len(p.m), Equals, 1)
+	c.Check(len(p.c), Equals, 1)
+	c.Check(len(p.k), Equals, 1)
+}
+
 // ----------------------------------------------------------------------------
 
 // tests all combinations of delimiters, leading and/or trailing whitespace and newlines.