Merge branch 'rework_errors' into partial

src/bin.rs

@@ -8,6 +8,7 @@ use renderer::DustRenderer;
 use renderer::Loopable;
 use renderer::RenderError;
 use renderer::Renderable;
+use renderer::WalkError;
 use renderer::Walkable;
 use std::env;
 use std::fs;
@@ -91,67 +92,48 @@ impl Renderable for serde_json::Value {
 }
 
 impl Walkable for serde_json::Value {
-    fn walk(&self, segment: &str) -> Result<&dyn ContextElement, RenderError> {
+    fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError> {
         match self {
-            serde_json::Value::Null => Err(RenderError::CantWalk {
+            serde_json::Value::Null => Err(WalkError::CantWalk),
-                segment: segment.to_string(),
+            serde_json::Value::Bool(_boolean) => Err(WalkError::CantWalk),
-                elem: self,
+            serde_json::Value::Number(_num) => Err(WalkError::CantWalk),
-            }),
+            serde_json::Value::String(_string) => Err(WalkError::CantWalk),
-            serde_json::Value::Bool(_boolean) => Err(RenderError::CantWalk {
+            serde_json::Value::Array(_arr) => Err(WalkError::CantWalk),
-                segment: segment.to_string(),
+            serde_json::Value::Object(obj) => obj
-                elem: self,
+                .get(segment)
-            }),
-            serde_json::Value::Number(_num) => Err(RenderError::CantWalk {
-                segment: segment.to_string(),
-                elem: self,
-            }),
-            serde_json::Value::String(_string) => Err(RenderError::CantWalk {
-                segment: segment.to_string(),
-                elem: self,
-            }),
-            serde_json::Value::Array(_arr) => Err(RenderError::CantWalk {
-                segment: segment.to_string(),
-                elem: self,
-            }),
-            serde_json::Value::Object(obj) => {
-                obj.get(segment)
                 .map(|val| val as _)
-                    .ok_or(RenderError::WontWalk {
+                .ok_or(WalkError::CantWalk),
-                        segment: segment.to_string(),
-                        elem: self,
-                    })
-            }
         }
     }
 }
 
 impl Loopable for serde_json::Value {
-    fn get_loop_elements(&self) -> Result<Vec<&dyn ContextElement>, RenderError> {
+    fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
         match self {
-            serde_json::Value::Null => Ok(Vec::new()),
+            serde_json::Value::Null => Vec::new(),
             serde_json::Value::Bool(boolean) => {
                 if *boolean {
-                    Ok(vec![self])
+                    vec![self]
                 } else {
-                    Ok(Vec::new())
+                    Vec::new()
                 }
             }
-            serde_json::Value::Number(_num) => Ok(vec![self]),
+            serde_json::Value::Number(_num) => vec![self],
             serde_json::Value::String(string_value) => {
                 if string_value.is_empty() {
-                    Ok(Vec::new())
+                    Vec::new()
                 } else {
-                    Ok(vec![self])
+                    vec![self]
                 }
             }
             serde_json::Value::Array(array_value) => {
                 if array_value.is_empty() {
-                    Ok(Vec::new())
+                    Vec::new()
                 } else {
-                    Ok(array_value.iter().map(|x| x as _).collect())
+                    array_value.iter().map(|x| x as _).collect()
                 }
             }
-            serde_json::Value::Object(_obj) => Ok(vec![self]),
+            serde_json::Value::Object(_obj) => vec![self],
         }
     }
 }

src/renderer/context_element.rs

@@ -1,11 +1,12 @@
 use crate::parser::Filter;
 use crate::renderer::errors::RenderError;
+use crate::renderer::errors::WalkError;
 use std::fmt::Debug;
 
 pub trait ContextElement: Debug + Walkable + Renderable + Loopable {}
 
 pub trait Walkable {
-    fn walk(&self, segment: &str) -> Result<&dyn ContextElement, RenderError>;
+    fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError>;
 }
 
 pub trait Renderable {
@@ -22,5 +23,5 @@ pub trait Loopable {
     /// once with the context being the element at that path. Finally,
     /// if its an array-like value then it will render n-times, once
     /// for each element of the array.
-    fn get_loop_elements(&self) -> Result<Vec<&dyn ContextElement>, RenderError>;
+    fn get_loop_elements(&self) -> Vec<&dyn ContextElement>;
 }

src/renderer/errors.rs

@@ -1,27 +1,16 @@
-use crate::renderer::context_element::ContextElement;
 use std::error;
 use std::fmt;
 
-pub enum RenderError<'a> {
+/// Fatal errors while rendering.
+///
+/// A RenderError will halt rendering.
+pub enum RenderError {
     Generic(String),
-    /// For when walking is absolutely impossible
+    TemplateNotFound(String),
-    CantWalk {
+}
-        segment: String,
+
-        elem: &'a dyn ContextElement,
+pub enum WalkError {
-    },
+    CantWalk,
-    /// For when walking fails (example, a missing key on a map)
-    WontWalk {
-        segment: String,
-        elem: &'a dyn ContextElement,
-    },
-    NotFound {
-        path: &'a Vec<&'a str>,
-        breadcrumbs: Vec<&'a dyn ContextElement>,
-    },
-    /// Attempting to render and unrenderable type (for example, an object without any filters)
-    CantRender {
-        elem: &'a dyn ContextElement,
-    },
 }
 
 #[derive(Clone)]
@@ -29,43 +18,51 @@ pub struct CompileError {
     pub message: String,
 }
 
-impl fmt::Display for RenderError<'_> {
+impl fmt::Display for RenderError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             RenderError::Generic(msg) => write!(f, "{}", msg),
-            RenderError::CantWalk { segment, elem } => {
+            RenderError::TemplateNotFound(name) => {
-                write!(f, "Tried to walk to {} from {:?}", segment, elem)
+                write!(f, "No template named {} in context", name)
-            }
-            RenderError::WontWalk { segment, elem } => {
-                write!(f, "Failed to walk to {} from {:?}", segment, elem)
-            }
-            RenderError::CantRender { elem } => write!(f, "Cant render {:?}", elem),
-            RenderError::NotFound { path, breadcrumbs } => {
-                write!(f, "Could not find {:?} in {:?}", path, breadcrumbs)
             }
         }
     }
 }
 
-impl fmt::Debug for RenderError<'_> {
+impl fmt::Debug for RenderError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             RenderError::Generic(msg) => write!(f, "{}", msg),
-            RenderError::CantWalk { segment, elem } => {
+            RenderError::TemplateNotFound(name) => {
-                write!(f, "Tried to walk to {} from {:?}", segment, elem)
+                write!(f, "No template named {} in context", name)
-            }
-            RenderError::WontWalk { segment, elem } => {
-                write!(f, "Failed to walk to {} from {:?}", segment, elem)
-            }
-            RenderError::CantRender { elem } => write!(f, "Cant render {:?}", elem),
-            RenderError::NotFound { path, breadcrumbs } => {
-                write!(f, "Could not find {:?} in {:?}", path, breadcrumbs)
             }
         }
     }
 }
 
-impl error::Error for RenderError<'_> {
+impl error::Error for RenderError {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        None
+    }
+}
+
+impl fmt::Display for WalkError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            WalkError::CantWalk => write!(f, "Failed to walk"),
+        }
+    }
+}
+
+impl fmt::Debug for WalkError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            WalkError::CantWalk => write!(f, "Failed to walk"),
+        }
+    }
+}
+
+impl error::Error for WalkError {
     fn source(&self) -> Option<&(dyn error::Error + 'static)> {
         None
     }

src/renderer/mod.rs

@@ -11,6 +11,7 @@ pub use context_element::Renderable;
 pub use context_element::Walkable;
 pub use errors::CompileError;
 pub use errors::RenderError;
+pub use errors::WalkError;
 pub use renderer::compile_template;
 pub use renderer::CompiledTemplate;
 pub use renderer::DustRenderer;

src/renderer/parameters_context.rs

@@ -4,6 +4,7 @@ use crate::renderer::context_element::ContextElement;
 use crate::renderer::Loopable;
 use crate::renderer::RenderError;
 use crate::renderer::Renderable;
+use crate::renderer::WalkError;
 use crate::renderer::Walkable;
 use std::collections::HashMap;
 
@@ -38,17 +39,15 @@ impl<'a> Renderable for ParametersContext<'a> {
 }
 
 impl<'a> Loopable for ParametersContext<'a> {
-    fn get_loop_elements(&self) -> Result<Vec<&dyn ContextElement>, RenderError> {
+    fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
-        Ok(vec![self])
+        // TODO: Would this even ever be called? Won't matter, but I'd like to know.
+        vec![self]
     }
 }
 
 impl<'a> Walkable for ParametersContext<'a> {
-    fn walk(&self, segment: &str) -> Result<&dyn ContextElement, RenderError> {
+    fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError> {
         // TODO: Actually implement
-        Err(RenderError::CantWalk {
+        Err(WalkError::CantWalk)
-            segment: segment.to_string(),
-            elem: self,
-        })
     }
 }

src/renderer/renderer.rs

@@ -7,6 +7,7 @@ use crate::parser::TemplateElement;
 use crate::renderer::context_element::ContextElement;
 use crate::renderer::errors::CompileError;
 use crate::renderer::errors::RenderError;
+use crate::renderer::errors::WalkError;
 use crate::renderer::parameters_context::ParametersContext;
 use std::collections::HashMap;
 
@@ -50,14 +51,11 @@ impl<'a> DustRenderer<'a> {
         &'a self,
         name: &str,
         breadcrumbs: &Vec<&'a dyn ContextElement>,
-    ) -> Result<String, RenderError<'a>> {
+    ) -> Result<String, RenderError> {
         let main_template = match self.templates.get(name) {
             Some(tmpl) => tmpl,
             None => {
-                return Err(RenderError::Generic(format!(
+                return Err(RenderError::TemplateNotFound(name.to_owned()));
-                    "No template named {} in context",
-                    name
-                )));
             }
         };
         self.render_body(&main_template.contents, breadcrumbs)
@@ -67,7 +65,7 @@ impl<'a> DustRenderer<'a> {
         &'a self,
         body: &'a Body,
         breadcrumbs: &Vec<&'a dyn ContextElement>,
-    ) -> Result<String, RenderError<'a>> {
+    ) -> Result<String, RenderError> {
         let mut output = String::new();
         for elem in &body.elements {
             match elem {
@@ -85,7 +83,7 @@ impl<'a> DustRenderer<'a> {
         &'a self,
         tag: &'a DustTag,
         breadcrumbs: &Vec<&'a dyn ContextElement>,
-    ) -> Result<String, RenderError<'a>> {
+    ) -> Result<String, RenderError> {
         match tag {
             DustTag::DTComment(_comment) => (),
             DustTag::DTSpecial(special) => {
@@ -101,21 +99,20 @@ impl<'a> DustRenderer<'a> {
             DustTag::DTReference(reference) => {
                 let val = walk_path(breadcrumbs, &reference.path.keys);
                 match val {
-                    Err(RenderError::NotFound { .. }) => return Ok("".to_owned()),
+                    Err(WalkError::CantWalk) => return Ok("".to_owned()),
                     Ok(final_val) => {
-                        let loop_elements = final_val.get_loop_elements()?;
+                        let loop_elements = final_val.get_loop_elements();
                         if loop_elements.is_empty() {
                             return Ok("".to_owned());
                         } else {
                             return final_val.render(&reference.filters);
                         }
                     }
-                    Err(render_error) => return Err(render_error),
                 }
             }
             DustTag::DTSection(container) => {
                 let val = walk_path(breadcrumbs, &container.path.keys);
-                let loop_elements: Vec<&dyn ContextElement> = self.get_loop_elements(val)?;
+                let loop_elements: Vec<&dyn ContextElement> = self.get_loop_elements(val);
                 if loop_elements.is_empty() {
                     // Oddly enough if the value is falsey (like
                     // an empty array or null), Dust uses the
@@ -145,7 +142,7 @@ impl<'a> DustRenderer<'a> {
             }
             DustTag::DTExists(container) => {
                 let val = walk_path(breadcrumbs, &container.path.keys);
-                let loop_elements: Vec<&dyn ContextElement> = self.get_loop_elements(val)?;
+                let loop_elements: Vec<&dyn ContextElement> = self.get_loop_elements(val);
                 if loop_elements.is_empty() {
                     return match &container.else_contents {
                         Some(body) => self.render_body(&body, breadcrumbs),
@@ -160,7 +157,7 @@ impl<'a> DustRenderer<'a> {
             }
             DustTag::DTNotExists(container) => {
                 let val = walk_path(breadcrumbs, &container.path.keys);
-                let loop_elements: Vec<&dyn ContextElement> = self.get_loop_elements(val)?;
+                let loop_elements: Vec<&dyn ContextElement> = self.get_loop_elements(val);
                 if !loop_elements.is_empty() {
                     return match &container.else_contents {
                         Some(body) => self.render_body(&body, breadcrumbs),
@@ -196,13 +193,11 @@ impl<'a> DustRenderer<'a> {
     /// block, this will return an empty vector.
     fn get_loop_elements<'b>(
         &'a self,
-        walk_result: Result<&'b dyn ContextElement, RenderError<'b>>,
+        walk_result: Result<&'b dyn ContextElement, WalkError>,
-    ) -> Result<Vec<&'b dyn ContextElement>, RenderError<'b>> {
+    ) -> Vec<&'b dyn ContextElement> {
-        if let Err(RenderError::NotFound { .. }) = walk_result {
+        match walk_result {
-            // If reference does not exist in the context, render the else block
+            Err(WalkError::CantWalk) => Vec::new(),
-            Ok(vec![])
+            Ok(walk_target) => walk_target.get_loop_elements(),
-        } else {
-            Ok(walk_result?.get_loop_elements()?)
         }
     }
 }
@@ -216,50 +211,46 @@ enum WalkResult<'a> {
 fn walk_path_from_single_level<'a>(
     context: &'a dyn ContextElement,
     path: &Vec<&str>,
-) -> Result<WalkResult<'a>, RenderError<'a>> {
+) -> WalkResult<'a> {
     if path.is_empty() {
-        return Ok(WalkResult::FullyWalked(context));
+        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);
-        if let Err(RenderError::WontWalk { .. }) = new_val {
+        match output.walk(elem) {
-            return Ok(walk_failure);
+            Err(WalkError::CantWalk { .. }) => {
-        } else if let Err(RenderError::CantWalk { .. }) = new_val {
+                return walk_failure;
-            return Ok(walk_failure);
             }
+            Ok(new_val) => {
                 walk_failure = WalkResult::PartialWalk;
-        output = new_val?;
+                output = new_val;
+            }
+        }
     }
 
-    Ok(WalkResult::FullyWalked(output))
+    WalkResult::FullyWalked(output)
 }
 
 fn walk_path<'a>(
     breadcrumbs: &Vec<&'a dyn ContextElement>,
     path: &'a Vec<&str>,
-) -> Result<&'a dyn ContextElement, RenderError<'a>> {
+) -> Result<&'a dyn ContextElement, WalkError> {
     for context in breadcrumbs.iter().rev() {
-        match walk_path_from_single_level(*context, path)? {
+        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(RenderError::NotFound {
+                return Err(WalkError::CantWalk);
-                    path: path,
-                    breadcrumbs: breadcrumbs.clone(),
-                });
             }
             WalkResult::FullyWalked(new_context) => return Ok(new_context),
         }
     }
-    Err(RenderError::NotFound {
+    Err(WalkError::CantWalk)
-        path: path,
-        breadcrumbs: breadcrumbs.clone(),
-    })
 }
 
 #[cfg(test)]
@@ -291,57 +282,48 @@ mod tests {
     impl<I: ContextElement> Renderable for HashMap<&str, I> {
         fn render(&self, _filters: &Vec<Filter>) -> Result<String, RenderError> {
             // TODO: handle the filters
-            Err(RenderError::CantRender { elem: self })
+            Ok("[object Object]".to_owned())
         }
     }
 
     impl<I: ContextElement> Walkable for HashMap<&str, I> {
-        fn walk(&self, segment: &str) -> Result<&dyn ContextElement, RenderError> {
+        fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError> {
-            let child = self.get(segment).ok_or(RenderError::WontWalk {
+            let child = self.get(segment).ok_or(WalkError::CantWalk)?;
-                segment: segment.to_string(),
-                elem: self,
-            })?;
             Ok(child)
         }
     }
 
     impl Walkable for &str {
-        fn walk(&self, segment: &str) -> Result<&dyn ContextElement, RenderError> {
+        fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError> {
-            Err(RenderError::CantWalk {
+            Err(WalkError::CantWalk)
-                segment: segment.to_string(),
-                elem: self,
-            })
         }
     }
 
     impl Walkable for u32 {
-        fn walk(&self, segment: &str) -> Result<&dyn ContextElement, RenderError> {
+        fn walk(&self, segment: &str) -> Result<&dyn ContextElement, WalkError> {
-            Err(RenderError::CantWalk {
+            Err(WalkError::CantWalk)
-                segment: segment.to_string(),
-                elem: self,
-            })
         }
     }
 
     impl Loopable for &str {
-        fn get_loop_elements(&self) -> Result<Vec<&dyn ContextElement>, RenderError> {
+        fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
             if self.is_empty() {
-                Ok(Vec::new())
+                Vec::new()
             } else {
-                Ok(vec![self])
+                vec![self]
             }
         }
     }
 
     impl Loopable for u32 {
-        fn get_loop_elements(&self) -> Result<Vec<&dyn ContextElement>, RenderError> {
+        fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
-            Ok(vec![self])
+            vec![self]
         }
     }
 
     impl<I: ContextElement> Loopable for HashMap<&str, I> {
-        fn get_loop_elements(&self) -> Result<Vec<&dyn ContextElement>, RenderError> {
+        fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
-            Ok(vec![self])
+            vec![self]
         }
     }