Update IterationContext to be an IntoContextElement and finish implementing section.

src/renderer/iteration_context.rs

@@ -1,6 +1,9 @@
+use crate::renderer::breadcrumb_tree::BreadcrumbTreeElement;
 use crate::renderer::context_element::CompareContextElement;
 use crate::renderer::context_element::ContextElement;
+use crate::renderer::context_element::IceResult;
 use crate::renderer::context_element::IntoContextElement;
+use crate::renderer::DustRenderer;
 use crate::renderer::Loopable;
 use crate::renderer::RenderError;
 use crate::renderer::Renderable;
@@ -16,7 +19,7 @@ use std::cmp::Ordering;
 /// Functions the same as the injected parameters contexts for
 /// helpers/partials with parameters but this has no need for storing
 /// breadcrumbs since its simply storing two integers.
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub struct IterationContext {
     idx: OwnedLiteral,
     len: OwnedLiteral,
@@ -32,32 +35,13 @@ impl IterationContext {
     }
 }
 
-impl ContextElement for IterationContext {}
-
-impl Truthiness for IterationContext {
-    fn is_truthy(&self) -> bool {
-        // TODO: Would this even ever be called? Won't matter, but I'd
-        // like to know. Since it is injected 1 above the current
-        // context, we wouldn't be able to access it with `{.}`.
-        true
-    }
-}
-
-impl Renderable for IterationContext {
-    fn render(&self, _filters: &Vec<Filter>) -> Result<String, RenderError> {
-        // TODO: Would this even ever be called? Won't matter, but I'd
-        // like to know. Since it is injected 1 above the current
-        // context, we wouldn't be able to access it with `{.}`.
-        Ok("[object Object]".to_owned())
-    }
-}
-
-impl Loopable for IterationContext {
-    fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
-        // TODO: Would this even ever be called? Won't matter, but I'd
-        // like to know. Since it is injected 1 above the current
-        // context, we wouldn't be able to access it with `{.}`.
-        Vec::new()
+impl IntoContextElement for IterationContext {
+    fn into_context_element<'b>(
+        &'b self,
+        renderer: &DustRenderer,
+        breadcrumbs: &'b Vec<BreadcrumbTreeElement<'b>>,
+    ) -> Option<IceResult<'b>> {
+        panic!("into_context_element cannot be called on pseudo elements");
     }
 }
 
@@ -74,15 +58,3 @@ impl Walkable for IterationContext {
         true
     }
 }
-
-impl CompareContextElement for IterationContext {
-    fn equals(&self, other: &dyn ContextElement) -> bool {
-        // TODO: Does this ever happen? perhaps I should have a panic here.
-        false
-    }
-
-    fn partial_compare(&self, other: &dyn ContextElement) -> Option<Ordering> {
-        // TODO: Does this ever happen? perhaps I should have a panic here.
-        None
-    }
-}

src/renderer/mod.rs

@@ -4,7 +4,7 @@ mod breadcrumb_tree;
 mod context_element;
 mod errors;
 mod inline_partial_tree;
-// mod iteration_context;
+mod iteration_context;
 mod parameters_context;
 mod renderer;
 mod tree_walking;

src/renderer/renderer.rs

@@ -15,6 +15,7 @@ use crate::renderer::errors::RenderError;
 use crate::renderer::errors::WalkError;
 use crate::renderer::inline_partial_tree::extract_inline_partials;
 use crate::renderer::inline_partial_tree::InlinePartialTreeElement;
+use crate::renderer::iteration_context::IterationContext;
 use crate::renderer::parameters_context::ParametersContext;
 use crate::renderer::tree_walking::walk_path;
 use std::borrow::Borrow;
@@ -170,8 +171,7 @@ impl<'a> DustRenderer<'a> {
                 let val = walk_path(breadcrumbs, &container.path.keys)
                     .map(|ice| ice.into_context_element(self, breadcrumbs));
                 match val {
-                    Err(WalkError::CantWalk) => {
-                        // TODO
+                    Err(WalkError::CantWalk) | Ok(None) => {
                         let new_breadcrumbs = self.new_breadcrumbs_section(
                             breadcrumbs,
                             None,
@@ -179,9 +179,84 @@ impl<'a> DustRenderer<'a> {
                             &container.explicit_context,
                             None,
                         );
+                        return self.render_maybe_body(
+                            &container.else_contents,
+                            new_breadcrumbs.as_ref().unwrap_or(breadcrumbs),
+                            blocks,
+                        );
                     }
-                    Ok(final_val) => {
-                        // TODO
+                    Ok(Some(final_val)) => {
+                        let context_element = final_val.get_context_element_reference();
+                        return if context_element.is_truthy() {
+                            match &container.contents {
+                                None => Ok("".to_owned()),
+                                Some(body) => {
+                                    let loop_elements: Vec<&dyn ContextElement> =
+                                        context_element.get_loop_elements();
+                                    if loop_elements.is_empty() {
+                                        // Scalar value
+                                        let new_breadcrumbs = self.new_breadcrumbs_section(
+                                            breadcrumbs,
+                                            None,
+                                            Some(&injected_context),
+                                            &container.explicit_context,
+                                            Some(context_element),
+                                        );
+                                        self.render_body(
+                                            body,
+                                            new_breadcrumbs.as_ref().unwrap_or(breadcrumbs),
+                                            blocks,
+                                        )
+                                    } else {
+                                        // Array-like value
+                                        let total_length = loop_elements.len();
+                                        let rendered_results: Result<Vec<String>, RenderError> =
+                                            loop_elements
+                                                .into_iter()
+                                                .enumerate()
+                                                .map(|(i, array_elem)| {
+                                                    let index_context =
+                                                        IterationContext::new(i, total_length);
+                                                    let new_breadcrumbs = self
+                                                        .new_breadcrumbs_section(
+                                                            breadcrumbs,
+                                                            Some(&index_context),
+                                                            Some(&injected_context),
+                                                            &container.explicit_context,
+                                                            Some(array_elem),
+                                                        );
+                                                    self.render_body(
+                                                        &body,
+                                                        new_breadcrumbs
+                                                            .as_ref()
+                                                            .unwrap_or(breadcrumbs),
+                                                        blocks,
+                                                    )
+                                                })
+                                                .collect();
+                                        let rendered_slice: &[String] = &rendered_results?;
+                                        return Ok(rendered_slice.join(""));
+                                    }
+                                }
+                            }
+                        } else {
+                            // Oddly enough if the value is falsey (like
+                            // an empty array or null), Dust uses the
+                            // original context before walking the path as
+                            // the context for rendering the else block
+                            let new_breadcrumbs = self.new_breadcrumbs_section(
+                                breadcrumbs,
+                                None,
+                                Some(&injected_context),
+                                &container.explicit_context,
+                                None,
+                            );
+                            self.render_maybe_body(
+                                &container.else_contents,
+                                new_breadcrumbs.as_ref().unwrap_or(breadcrumbs),
+                                blocks,
+                            )
+                        };
                     }
                 }
             }
@@ -247,7 +322,6 @@ impl<'a> DustRenderer<'a> {
         injected_context: Option<&'b dyn IntoContextElement>,
         explicit_context: &Option<Path<'b>>,
     ) -> Option<Vec<BreadcrumbTreeElement<'b>>> {
-
         // If none of the additional contexts are present, return None
         // to signal that the original breadcrumbs should be used
         // rather than incurring a copy here.
@@ -270,8 +344,11 @@ impl<'a> DustRenderer<'a> {
             // added after the current context but before the explicit
             // context.
             match explicit_context {
-                None => new_stack.insert(Self::get_index_of_first_non_pseudo_element(&new_stack).unwrap_or(0), BreadcrumbTreeElement::from_borrowed(ctx)),
-                _ => new_stack.push(BreadcrumbTreeElement::from_borrowed(ctx))
+                None => new_stack.insert(
+                    Self::get_index_of_first_non_pseudo_element(&new_stack).unwrap_or(0),
+                    BreadcrumbTreeElement::from_borrowed(ctx),
+                ),
+                _ => new_stack.push(BreadcrumbTreeElement::from_borrowed(ctx)),
             }
         });
 
@@ -308,11 +385,12 @@ impl<'a> DustRenderer<'a> {
         final_filters
     }
 
-    fn get_index_of_first_non_pseudo_element<'b>(breadcrumbs: &'b Vec<BreadcrumbTreeElement<'b>>) -> Option<usize>
-    {
-        breadcrumbs
-            .iter()
-            .rposition(|b| std::borrow::Borrow::<dyn IntoContextElement + 'b>::borrow(b).is_pseudo_element())
+    fn get_index_of_first_non_pseudo_element<'b>(
+        breadcrumbs: &'b Vec<BreadcrumbTreeElement<'b>>,
+    ) -> Option<usize> {
+        breadcrumbs.iter().rposition(|b| {
+            std::borrow::Borrow::<dyn IntoContextElement + 'b>::borrow(b).is_pseudo_element()
+        })
     }
 }