add Object#while:do:else: & Block#while_true:else:

lib/block.fy

@@ -51,6 +51,18 @@ class Block {
 
   alias_method: 'while_do: for: 'while_true:
 
+  def while_true: block else: alternative {
+    """
+    @block @Block@ to be called while @self yields @true.
+    @alternative @Block@ to be called if @self never yielded @true.
+    """
+
+    if: call then: {
+      block call
+      while_true: block
+    } else: alternative
+  }
+
   def until_do: block {
     """
     @block @Block@ to be called while @self yields @nil or @false.

lib/object.fy

@@ -240,7 +240,17 @@ class Object {
           cond_block while_do: body_block
     """
 
-    cond_block while_do: body_block
+    cond_block while_true: body_block
+  }
+
+  def while: condition do: body else: alternative {
+    """
+    @condition @Block@ to be used as condition for while loop.
+    @body @Block@ to be called while @condition yields @true.
+    @alternative @Block@ to be called if @body never got called (@condition never yielded @true).
+    """
+
+    condition while_true: body else: alternative
   }
 
   def until: cond_block do: body_block {

tests/block.fy

@@ -32,6 +32,24 @@ FancySpec describe: Block with: {
     i is be: { i >= 10 }
   }
 
+  it: "calls a block while another is true or calls the alternative" with: 'while_true:else: when: {
+    i = 0
+    { i < 10 } while_true: {
+      i = i + 1
+    } else: {
+      i = "nope"
+    }
+    i is: 10
+
+    i = 0
+    { i > 10 } while_true: {
+      i = i + 1
+    } else: {
+      i = "nope"
+    }
+    i is: "nope"
+  }
+
   it: "calls a block while another is not true (boolean false)" with: 'while_false: when: {
     i = 0
     {i == 10} while_false: {