Added Object#do: which allows message cascading style code by calling…

… the code with the receiver as the receiver (using Block#call_with_receiver:).

lib/object.fy

@@ -542,4 +542,26 @@ class Object {
     { return 0 } if: (self == other)
     return 1 # greater or equal to other
   }
+
+  def do: block {
+    """
+    @block @Block@ to be called in the context of @self.
+
+    Helper method that calls @block with @self as the receiver.
+    This allows message cascading like code, e.g.:
+
+        some_complex_object do: {
+          method_1: arg1
+          method_2: arg2
+          method_3: arg3
+        }
+
+        # this is the same as:
+        some_complex_object method_1: arg1
+        some_complex_object method_2: arg2
+        some_complex_object method_3: arg3
+    """
+
+    block call_with_receiver: self
+  }
 }

tests/object.fy

@@ -193,4 +193,18 @@ FancySpec describe: Object with: {
     self test is == 42
     test is == (self test)
   }
+
+  it: "should call a given block in the context of the receiver (like a message cascade)" for: 'do: when: {
+    arr = []
+    arr do: {
+      << 1
+      << 2
+      << 3
+      select!: 'even?
+    }
+    arr is == [2]
+    arr do: {
+      is == [2] # same
+    }
+  }
 }