Partial simple is working.

src/renderer/mod.rs

@@ -4,6 +4,7 @@ mod context_element;
 mod errors;
 mod parameters_context;
 mod renderer;
+mod walking;
 
 pub use context_element::ContextElement;
 pub use context_element::Loopable;

src/renderer/parameters_context.rs

@@ -1,6 +1,7 @@
 use crate::parser::KVPair;
 use crate::parser::{Filter, RValue};
 use crate::renderer::context_element::ContextElement;
+use crate::renderer::walking::walk_path;
 use crate::renderer::Loopable;
 use crate::renderer::RenderError;
 use crate::renderer::Renderable;
@@ -34,20 +35,52 @@ impl<'a> ContextElement for ParametersContext<'a> {}
 
 impl<'a> Renderable for ParametersContext<'a> {
     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<'a> Loopable for ParametersContext<'a> {
     fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
-        // TODO: Would this even ever be called? Won't matter, but I'd like to know.
+        // 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![self]
     }
 }
 
 impl<'a> Walkable for ParametersContext<'a> {
     fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError> {
-        // TODO: Actually implement
+        let rval = self.params.get(segment).ok_or(WalkError::CantWalk)?;
+        match rval {
+            RValue::RVPath(path) => walk_path(self.breadcrumbs, &path.keys),
+            RValue::RVString(text) => Ok(text),
+        }
+    }
+}
+
+impl ContextElement for String {}
+
+impl Renderable for String {
+    fn render(&self, _filters: &Vec<Filter>) -> Result<String, RenderError> {
+        Ok(self.clone())
+    }
+}
+
+impl Loopable for String {
+    fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
+        if self.is_empty() {
+            Vec::new()
+        } else {
+            vec![self]
+        }
+    }
+}
+
+impl Walkable for String {
+    fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError> {
         Err(WalkError::CantWalk)
     }
 }

src/renderer/renderer.rs

@@ -9,6 +9,7 @@ use crate::renderer::errors::CompileError;
 use crate::renderer::errors::RenderError;
 use crate::renderer::errors::WalkError;
 use crate::renderer::parameters_context::ParametersContext;
+use crate::renderer::walking::walk_path;
 use std::collections::HashMap;
 
 #[derive(Clone, Debug)]
@@ -202,57 +203,6 @@ impl<'a> DustRenderer<'a> {
     }
 }
 
-enum WalkResult<'a> {
-    NoWalk,
-    PartialWalk,
-    FullyWalked(&'a dyn ContextElement),
-}
-
-fn walk_path_from_single_level<'a>(
-    context: &'a dyn ContextElement,
-    path: &Vec<&str>,
-) -> WalkResult<'a> {
-    if path.is_empty() {
-        return WalkResult::FullyWalked(context);
-    }
-
-    let mut walk_failure = WalkResult::NoWalk;
-    let mut output = context;
-    for elem in path.iter() {
-        let new_val = output.walk(elem);
-        match output.walk(elem) {
-            Err(WalkError::CantWalk { .. }) => {
-                return walk_failure;
-            }
-            Ok(new_val) => {
-                walk_failure = WalkResult::PartialWalk;
-                output = new_val;
-            }
-        }
-    }
-
-    WalkResult::FullyWalked(output)
-}
-
-fn walk_path<'a>(
-    breadcrumbs: &Vec<&'a dyn ContextElement>,
-    path: &'a Vec<&str>,
-) -> Result<&'a dyn ContextElement, WalkError> {
-    for context in breadcrumbs.iter().rev() {
-        match walk_path_from_single_level(*context, path) {
-            // If no walking was done at all, keep looping
-            WalkResult::NoWalk => {}
-            // If we partially walked then stop trying to find
-            // anything
-            WalkResult::PartialWalk => {
-                return Err(WalkError::CantWalk);
-            }
-            WalkResult::FullyWalked(new_context) => return Ok(new_context),
-        }
-    }
-    Err(WalkError::CantWalk)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;