Add proper impl for templating

Signed-off-by: Marcel Müller <neikos@neikos.email>

src/ast/mod.rs

@@ -1,3 +1,4 @@
+use thiserror::Error;
 use winnow::Parser;
 use winnow::RecoverableParser;
 use winnow::combinator::alt;
@@ -113,9 +114,15 @@ impl ParserError<Input<'_>> for AstError {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Error)]
 pub struct AstFailure {}
 
+impl std::fmt::Display for AstFailure {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("TODO")
+    }
+}
+
 impl AstFailure {
     fn from_errors(_errors: Vec<AstError>, _input: &[TemplateToken]) -> AstFailure {
         AstFailure {}
@@ -217,7 +224,7 @@ mod tests {
     fn check_only_content() {
         let input = "Hello World";
 
-        let parsed = crate::parser::parse(input).unwrap();
+        let parsed = crate::parser::parse(input.into()).unwrap();
 
         let ast = parse(parsed.tokens()).unwrap();
 
@@ -239,7 +246,7 @@ mod tests {
     fn check_simple_variable_interpolation() {
         let input = "Hello {{= world }}";
 
-        let parsed = crate::parser::parse(input).unwrap();
+        let parsed = crate::parser::parse(input.into()).unwrap();
 
         let ast = parse(parsed.tokens()).unwrap();
 

src/emit/mod.rs

@@ -122,7 +122,7 @@ mod tests {
     fn check_simple_variable_interpolation() {
         let input = "Hello {{= world }}";
 
-        let parsed = crate::parser::parse(input).unwrap();
+        let parsed = crate::parser::parse(input.into()).unwrap();
 
         let ast = crate::ast::parse(parsed.tokens()).unwrap();
 

src/eval/mod.rs

@@ -8,14 +8,14 @@ use crate::emit::Instruction;
 use crate::input::TempleInput;
 
 #[derive(Debug, Error, Display)]
-enum EvalError {
+pub enum EvaluationError {
     /// An unknown variable was encountered: .0
     UnknownVariable(TempleInput),
     /// An explicit abort was requested
     ExplicitAbort,
 }
 
-fn execute(instructions: &[Instruction], global_context: &Context) -> Result<String, EvalError> {
+pub fn execute(instructions: &[Instruction], global_context: &Context) -> Result<String, EvaluationError> {
     let mut output = String::new();
 
     let mut scopes: HashMap<crate::emit::VariableSlot, serde_json::Value> = HashMap::new();
@@ -27,7 +27,7 @@ fn execute(instructions: &[Instruction], global_context: &Context) -> Result<Str
                 let value = global_context
                     .values
                     .get(name.as_str())
-                    .ok_or(EvalError::UnknownVariable(name.clone()))?;
+                    .ok_or(EvaluationError::UnknownVariable(name.clone()))?;
 
                 scopes.insert(*slot, value.clone());
             }
@@ -36,7 +36,7 @@ fn execute(instructions: &[Instruction], global_context: &Context) -> Result<Str
                 output.push_str(value);
             }
             Instruction::PushScope { inherit_parent: _ } => todo!(),
-            Instruction::Abort => return Err(EvalError::ExplicitAbort),
+            Instruction::Abort => return Err(EvaluationError::ExplicitAbort),
         }
     }
 
@@ -52,7 +52,7 @@ mod tests {
     fn check_simple_variable_interpolation() {
         let input = "Hello {{= world }}";
 
-        let parsed = crate::parser::parse(input).unwrap();
+        let parsed = crate::parser::parse(input.into()).unwrap();
 
         let ast = crate::ast::parse(parsed.tokens()).unwrap();
 

src/lib.rs

@@ -5,16 +5,36 @@ use displaydoc::Display;
 use serde::Serialize;
 use thiserror::Error;
 
+use crate::emit::Instruction;
+use crate::input::TempleInput;
+
 pub mod ast;
 pub mod emit;
 pub mod eval;
-pub mod parser;
 mod input;
+pub mod parser;
 
 #[derive(Debug, Error, Display)]
 pub enum TempleError {
     /// Could not parse the given template
-    ParseError {},
+    ParseError {
+        #[from]
+        source: parser::ParseFailure,
+    },
+    /// Invalid Template
+    AstError {
+        #[from]
+        source: ast::AstFailure,
+    },
+
+    /// An error occurred while evaluating
+    EvaluationError {
+        #[from]
+        source: eval::EvaluationError,
+    },
+
+    /// The template '{0}' could not be found
+    UnknownTemplate(String),
 }
 
 pub struct Temple {
@@ -37,17 +57,41 @@ impl Temple {
     pub fn add_template(
         &mut self,
         name: impl Into<String>,
-        value: impl AsRef<str>,
+        value: impl Into<TempleInput>,
     ) -> Result<(), TempleError> {
+        let source = value.into();
+        let parse = parser::parse(source.clone())?;
+        let ast = ast::parse(parse.tokens())?;
+
+        let instructions = emit::emit_machine(ast);
+
+        self.templates.insert(
+            name.into(),
+            Template {
+                source,
+                instructions,
+            },
+        );
+
         Ok(())
     }
 
-    fn render(&self, arg: &str, ctx: &Context) -> Result<String, TempleError> {
+    pub fn render(&self, name: &str, ctx: &Context) -> Result<String, TempleError> {
-        Ok(String::new())
+        let template = self
+            .templates
+            .get(name)
+            .ok_or_else(|| TempleError::UnknownTemplate(name.to_string()))?;
+
+        let res = eval::execute(&template.instructions, ctx)?;
+
+        Ok(res)
     }
 }
 
-struct Template {}
+struct Template {
+    source: TempleInput,
+    instructions: Vec<Instruction>,
+}
 
 pub struct Context {
     values: BTreeMap<String, serde_json::Value>,
@@ -155,6 +199,6 @@ mod tests {
 
         let rendered = temp.render("base", &ctx).unwrap();
 
-        insta::assert_snapshot!(rendered, @"")
+        insta::assert_snapshot!(rendered, @"Hello World")
     }
 }

src/parser/mod.rs

@@ -4,6 +4,7 @@ use annotate_snippets::AnnotationKind;
 use annotate_snippets::Level;
 use annotate_snippets::Renderer;
 use annotate_snippets::Snippet;
+use thiserror::Error;
 use winnow::LocatingSlice;
 use winnow::Parser;
 use winnow::RecoverableParser;
@@ -37,16 +38,22 @@ use crate::resume_after_cut;
 type Input<'input> = Recoverable<LocatingSlice<TempleInput>, ParseError>;
 type PResult<'input, T> = Result<T, ParseError>;
 
-#[derive(Debug)]
+#[derive(Debug, Error)]
 pub struct ParseFailure {
-    source: Arc<str>,
+    input: Arc<str>,
     errors: Vec<ParseError>,
 }
 
+impl std::fmt::Display for ParseFailure {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(&self.to_report())
+    }
+}
+
 impl ParseFailure {
-    fn from_errors(errors: Vec<ParseError>, input: &str) -> ParseFailure {
+    fn from_errors(errors: Vec<ParseError>, input: TempleInput) -> ParseFailure {
         ParseFailure {
-            source: Arc::from(input.to_string()),
+            input: Arc::from(input.to_string()),
             errors,
         }
     }
@@ -64,7 +71,7 @@ impl ParseFailure {
                             .unwrap_or("An error occurred while parsing"),
                     )
                     .element(
-                        Snippet::source(self.source.as_ref()).annotation(
+                        Snippet::source(self.input.as_ref()).annotation(
                             AnnotationKind::Primary
                                 .span(error.span.clone().map(|s| s.range).unwrap_or_else(|| 0..0)),
                         ),
@@ -294,9 +301,9 @@ impl TemplateToken {
     }
 }
 
-pub fn parse(input: &str) -> Result<ParsedTemplate, ParseFailure> {
+pub fn parse(input: TempleInput) -> Result<ParsedTemplate, ParseFailure> {
     let (_remaining, val, errors) =
-        parse_tokens.recoverable_parse(LocatingSlice::new(TempleInput::from(input)));
+        parse_tokens.recoverable_parse(LocatingSlice::new(input.clone()));
 
     if errors.is_empty()
         && let Some(val) = val
@@ -418,7 +425,7 @@ mod tests {
     #[test]
     fn parse_simple() {
         let input = "Hello There";
-        let output = parse(input);
+        let output = parse(input.into());
 
         insta::assert_debug_snapshot!(output, @r#"
         Ok(
@@ -437,7 +444,7 @@ mod tests {
     #[test]
     fn parse_interpolate() {
         let input = "Hello {{ there }}";
-        let output = parse(input);
+        let output = parse(input.into());
 
         insta::assert_debug_snapshot!(output, @r#"
         Ok(
@@ -480,12 +487,12 @@ mod tests {
     #[test]
     fn parse_interpolate_bad() {
         let input = "Hello {{ the2re }} {{ the@re }}";
-        let output = parse(input);
+        let output = parse(input.into());
 
         insta::assert_debug_snapshot!(output, @r#"
         Err(
             ParseFailure {
-                source: "Hello {{ the2re }} {{ the@re }}",
+                input: "Hello {{ the2re }} {{ the@re }}",
                 errors: [
                     ParseError {
                         message: Some(