Implement the contextDump helper.

src/renderer/renderer.rs

@@ -765,8 +765,41 @@ impl<'a> DustRenderer<'a> {
                 }
             }
             DustTag::DTHelperContextDump(parameterized_block) => {
-                //todo
-                todo!()
+                let param_map =
+                    ParametersContext::new(self, breadcrumbs, &parameterized_block.params, None);
+                let value = self.tap(breadcrumbs, &param_map, "key");
+                let destination = self.tap(breadcrumbs, &param_map, "to");
+                let value_rendered = match value.as_ref().map(|maybe_ice| {
+                    maybe_ice
+                        .as_ref()
+                        .map(|ice| ice.get_context_element_reference())
+                        .map(|ce| ce.render(&Vec::new()))
+                }) {
+                    Some(Ok(Ok(val))) => val,
+                    _ => "current".to_owned(),
+                };
+                let destination_rendered = match destination.as_ref().map(|maybe_ice| {
+                    maybe_ice
+                        .as_ref()
+                        .map(|ice| ice.get_context_element_reference())
+                        .map(|ce| ce.render(&Vec::new()))
+                }) {
+                    Some(Ok(Ok(val))) => val,
+                    _ => "output".to_owned(),
+                };
+                match (
+                    value_rendered.as_str(),
+                    destination_rendered.as_str(),
+                    breadcrumbs.last(),
+                ) {
+                    ("current", "output", None) => return Ok("{}".to_owned()),
+                    ("current", "console", None) => println!("{{}}"),
+                    ("current", "output", Some(bc)) => return Ok(format!("{:?}", bc)),
+                    ("current", "console", Some(bc)) => println!("{:?}", bc),
+                    ("full", "output", _) => return Ok(format!("{:?}", breadcrumbs)),
+                    ("full", "console", _) => println!("{:?}", breadcrumbs),
+                    _ => panic!("Unhandled contextDump parameters."),
+                }
             }
         }