src/error.rs

@@ -15,7 +15,6 @@ pub enum Error {
     UnexpectedSourceNode {
         expected: &'static str,
         actual: &'static str,
-        location: tree_sitter::Point,
     },
 
     ExpectedFieldName,
@@ -553,7 +552,7 @@ impl fmt::Display for Error {
                 macro_info.identifier,
                 macro_info.inputs
             ),
-            UnexpectedSourceNode { expected, actual, location } => write!(f, "Unexpected syntax at {location}. Expected {expected}, but found {actual}."),
+            UnexpectedSourceNode { expected, actual } => write!(f, "Unexpected source node. Expected {expected}, but found {actual}."),
             ExpectedFieldName => write!(f, "Expected a field name for this node, but none was found."),
             WrongTypeCombination { expected, actual } => write!(f, "Wrong type combination. Expected {expected}, found {actual}."),
             ExpectedChildNode { empty_node_sexp } => write!(f, "Expected this node to have a child, {empty_node_sexp}."),

src/interface.rs

@@ -1,8 +1,4 @@
 //! The top level of Dust's API with functions to interpret Dust code.
-//!
-//! You can use this library externally by calling either of the "eval"
-//! functions or by constructing your own Evaluator.
-use std::fmt::{self, Debug, Formatter};
 
 use serde::{Deserialize, Serialize};
 use tree_sitter::{Node, Parser, Tree as TSTree, TreeCursor};
@@ -34,9 +30,9 @@ pub fn eval(source: &str) -> Vec<Result<Value>> {
 /// # use dust_lib::*;
 /// let mut context = VariableMap::new();
 ///
-/// context.set_value("one".into(), 1.into());
-/// context.set_value("two".into(), 2.into());
-/// context.set_value("three".into(), 3.into());
+/// context.set_value("one".into(), 1.into()).unwrap(); // Do proper error handling here
+/// context.set_value("two".into(), 2.into()).unwrap(); // Do proper error handling here
+/// context.set_value("three".into(), 3.into()).unwrap(); // Do proper error handling here
 ///
 /// let dust_code = "four = 4 one + two + three + four";
 ///
@@ -47,12 +43,20 @@ pub fn eval(source: &str) -> Vec<Result<Value>> {
 /// ```
 pub fn eval_with_context(source: &str, context: &mut VariableMap) -> Vec<Result<Value>> {
     let mut parser = Parser::new();
+
     parser.set_language(language()).unwrap();
 
-    Evaluator::new(parser, context, source).run()
+    let tree = parser.parse(source, None).unwrap();
+    let mut cursor = tree.walk();
+    let evaluator = Evaluator::new(tree.clone(), source).unwrap();
+    let results = evaluator.run(context, &mut cursor, source);
+
+    println!("{results:?}");
+
+    results
 }
 
-trait EvaluatorTree: Sized {
+pub trait EvaluatorTree: Sized {
     /// Interpret the syntax tree at the given node and return the abstraction.
     ///
     /// This function is used to convert nodes in the Tree Sitter concrete
@@ -65,51 +69,33 @@ trait EvaluatorTree: Sized {
     fn new(node: Node, source: &str) -> Result<Self>;
 
     /// Execute dust code by traversing the tree
-    fn run() -> Vec<Result<Value>>;
+    fn run(
+        &self,
+        context: &mut VariableMap,
+        cursor: &mut TreeCursor,
+        source: &str,
+    ) -> Vec<Result<Value>>;
 }
 
 /// A collection of statements and comments interpreted from a syntax tree.
 ///
 /// The Evaluator turns a tree sitter concrete syntax tree into a vector of
 /// abstract trees called [Item][]s that can be run to execute the source code.
-pub struct Evaluator<'context, 'code> {
-    _parser: Parser,
-    context: &'context mut VariableMap,
-    source: &'code str,
-    tree: TSTree,
+#[derive(Debug)]
+pub struct Evaluator {
+    items: Vec<Item>,
 }
 
-impl Debug for Evaluator<'_, '_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        write!(f, "Evaluator context: {}", self.context)
-    }
-}
-
-impl<'context, 'code> Evaluator<'context, 'code> {
-    fn new(mut parser: Parser, context: &'context mut VariableMap, source: &'code str) -> Self {
-        let tree = parser.parse(source, None).unwrap();
-
-        Evaluator {
-            _parser: parser,
-            context,
-            source,
-            tree,
-        }
-    }
-
-    fn run(self) -> Vec<Result<Value>> {
-        let root_node = self.tree.root_node();
-        let mut cursor = self.tree.walk();
+impl Evaluator {
+    fn new(tree_sitter_tree: TSTree, source: &str) -> Result<Self> {
+        let root_node = tree_sitter_tree.root_node();
+        let mut cursor = tree_sitter_tree.walk();
         let mut items = Vec::new();
-        let mut results = Vec::new();
 
         for (index, node) in root_node.children(&mut cursor).enumerate() {
-            match Item::new(node, self.source) {
-                Ok(item) => items.push(item),
-                Err(error) => results.push(Err(error)),
-            }
+            let item = Item::new(node, source)?;
 
-            println!("{node:?}");
+            items.push(item);
 
             // This iterator will run forever without this check.
             if index == root_node.child_count() - 1 {
@@ -117,11 +103,22 @@ impl<'context, 'code> Evaluator<'context, 'code> {
             }
         }
 
-        for item in &items {
+        Ok(Evaluator { items })
+    }
+
+    fn run(
+        &self,
+        context: &mut VariableMap,
+        mut cursor: &mut TreeCursor,
+        source: &str,
+    ) -> Vec<Result<Value>> {
+        let mut results = Vec::with_capacity(self.items.len());
+
+        for item in &self.items {
             match item {
-                Item::Comment(comment) => results.push(Ok(Value::String(comment.to_string()))),
+                Item::Comment(comment) => results.push(Ok(Value::String(comment.clone()))),
                 Item::Statement(statement) => {
-                    results.push(statement.run(self.context, &mut cursor, self.source))
+                    results.push(statement.run(context, &mut cursor, source))
                 }
             }
         }
@@ -147,7 +144,6 @@ impl Item {
             return Err(Error::UnexpectedSourceNode {
                 expected: "item",
                 actual: node.kind(),
-                location: node.start_position(),
             });
         }
 
@@ -155,9 +151,9 @@ impl Item {
 
         if child.kind() == "comment" {
             let byte_range = node.byte_range();
-            let comment_text = &source[byte_range];
+            let value_string = &source[byte_range];
 
-            Ok(Item::Comment(comment_text.to_string()))
+            Ok(Item::Comment(value_string.to_string()))
         } else if child.kind() == "statement" {
             let child = node.child(0).unwrap();
             Ok(Item::Statement(Statement::new(child, source)?))
@@ -165,7 +161,6 @@ impl Item {
             Err(Error::UnexpectedSourceNode {
                 expected: "comment or statement",
                 actual: node.kind(),
-                location: node.start_position(),
             })
         }
     }
@@ -178,7 +173,7 @@ impl Item {
 /// referencing variables.
 #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
 pub enum Statement {
-    Expression(Expression),
+    Open(Expression),
 }
 
 impl Statement {
@@ -188,15 +183,13 @@ impl Statement {
         } else {
             node
         };
-
         let child = node.child(0).unwrap();
 
         match node.kind() {
-            "expression" => Ok(Self::Expression(Expression::new(child, source)?)),
+            "open_statement" => Ok(Self::Open(Expression::new(child, source)?)),
             _ => Err(Error::UnexpectedSourceNode {
-                expected: "expression",
+                expected: "open_statement",
                 actual: node.kind(),
-                location: node.start_position(),
             }),
         }
     }
@@ -208,7 +201,7 @@ impl Statement {
         source: &str,
     ) -> Result<Value> {
         match self {
-            Statement::Expression(expression) => expression.run(context, &mut cursor, source),
+            Statement::Open(expression) => expression.run(context, &mut cursor, source),
         }
     }
 }
@@ -217,31 +210,8 @@ impl Statement {
 pub enum Expression {
     Identifier(String),
     Value(Value),
+    Operation(Box<Operation>),
     ControlFlow(Box<ControlFlow>),
-    Assignment(Box<Assignment>),
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
-pub struct Assignment {
-    identifier: String,
-    statement: Statement,
-}
-
-impl Assignment {
-    pub fn new(node: Node, source: &str) -> Result<Self> {
-        let sexp = node.to_sexp();
-        println!("{sexp}");
-
-        let identifier_node = node.child(0).unwrap();
-        let statement_node = node.child(2).unwrap();
-        let identifier = source[identifier_node.byte_range()].to_string();
-        let statement = Statement::new(statement_node, source)?;
-
-        Ok(Self {
-            identifier,
-            statement,
-        })
-    }
 }
 
 impl Expression {
@@ -259,19 +229,18 @@ impl Expression {
             Ok(Self::Identifier(identifier.to_string()))
         } else if node.kind() == "value" {
             Ok(Expression::Value(Value::new(node, source)?))
+        } else if node.kind() == "operation" {
+            Ok(Expression::Operation(Box::new(Operation::new(
+                node, source,
+            )?)))
         } else if node.kind() == "control_flow" {
             Ok(Expression::ControlFlow(Box::new(ControlFlow::new(
                 node, source,
             )?)))
-        } else if node.kind() == "assignment" {
-            Ok(Expression::Assignment(Box::new(Assignment::new(
-                node, source,
-            )?)))
         } else {
             Err(Error::UnexpectedSourceNode {
-                expected: "identifier, operation, control_flow, assignment or value",
+                expected: "identifier, operation, control_flow or value",
                 actual: node.kind(),
-                location: node.start_position(),
             })
         }
     }
@@ -293,12 +262,64 @@ impl Expression {
                 }
             }
             Expression::Value(value) => Ok(value.clone()),
+            Expression::Operation(operation) => operation.run(context, &mut cursor, source),
             Expression::ControlFlow(control_flow) => control_flow.run(context, &mut cursor, source),
-            Expression::Assignment(_) => todo!(),
         }
     }
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct Operation {
+    left: Expression,
+    operator: String,
+    right: Expression,
+}
+
+impl Operation {
+    fn new(node: Node, source: &str) -> Result<Self> {
+        let first_child = node.child(0).unwrap();
+        let second_child = node.child(1).unwrap();
+        let third_child = node.child(2).unwrap();
+        let left = Expression::new(first_child, source)?;
+        let operator = second_child.child(0).unwrap().kind().to_string();
+        let right = Expression::new(third_child, source)?;
+
+        Ok(Operation {
+            left,
+            operator,
+            right,
+        })
+    }
+
+    fn run(
+        &self,
+        context: &mut VariableMap,
+        mut cursor: &mut TreeCursor,
+        source: &str,
+    ) -> Result<Value> {
+        let left = self.left.run(context, &mut cursor, source)?;
+        let right = self.right.run(context, &mut cursor, source)?;
+
+        match self.operator.as_str() {
+            "+" => left + right,
+            "-" => left - right,
+            "=" => {
+                if let Expression::Identifier(key) = &self.left {
+                    context.set_value(key, right)?;
+                }
+
+                Ok(Value::Empty)
+            }
+            "==" => Ok(Value::Boolean(left == right)),
+            _ => Err(Error::CustomMessage("Operator not supported.".to_string())),
+        }
+    }
+}
+
+/// Respresentation of an if-then-else logic gate.
+///
+/// A ControlFlow instance represents work to be done when the "run" method is
+/// called.
 #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
 pub struct ControlFlow {
     if_expression: Expression,
@@ -354,23 +375,14 @@ mod tests {
 
     #[test]
     fn evaluate_empty() {
-        assert_eq!(eval(""), vec![]);
-        assert_eq!(eval("x = 9"), vec![]);
-        assert_eq!(eval("'foo' + 'bar'"), vec![]);
+        assert_eq!(eval("()"), vec![Ok(Value::Empty)]);
+        assert_eq!(eval("x = 9"), vec![Ok(Value::Empty)]);
+        assert_eq!(eval("y = 'foobar'"), vec![Ok(Value::Empty)]);
     }
 
     #[test]
     fn evaluate_integer() {
         assert_eq!(eval("1"), vec![Ok(Value::Integer(1))]);
-        assert_eq!(eval("123"), vec![Ok(Value::Integer(123))]);
-        assert_eq!(eval("-666"), vec![Ok(Value::Integer(-666))]);
-    }
-
-    #[test]
-    fn evaluate_float() {
-        assert_eq!(eval("0.1"), vec![Ok(Value::Float(0.1))]);
-        assert_eq!(eval("12.3"), vec![Ok(Value::Float(12.3))]);
-        assert_eq!(eval("-6.66"), vec![Ok(Value::Float(-6.66))]);
     }
 
     #[test]

src/tools/gui.rs

@@ -9,7 +9,9 @@ use eframe::{
 };
 use egui_extras::{Column, StripBuilder, TableBuilder};
 
-use crate::{Error, Result, Table, Tool, ToolInfo, Value, ValueType, VariableMap};
+use crate::{
+    eval_with_context, Error, Result, Table, Tool, ToolInfo, Value, ValueType, VariableMap,
+};
 
 pub struct BarGraph;
 
@@ -169,7 +171,7 @@ impl eframe::App for PlotGui {
 
 pub struct GuiApp {
     text_edit_buffer: String,
-    _whale_context: VariableMap,
+    whale_context: VariableMap,
     eval_result: Result<Value>,
 }
 
@@ -177,7 +179,7 @@ impl GuiApp {
     pub fn new(result: Result<Value>) -> Self {
         GuiApp {
             text_edit_buffer: String::new(),
-            _whale_context: VariableMap::new(),
+            whale_context: VariableMap::new(),
             eval_result: result,
         }
     }

src/value/function.rs

@@ -22,7 +22,7 @@ impl Function {
         todo!()
     }
 
-    pub fn run_with_context(&self, _context: &mut VariableMap) -> Result<Value> {
+    pub fn run_with_context(&self, context: &mut VariableMap) -> Result<Value> {
         todo!()
     }
 }

src/value/mod.rs

@@ -187,7 +187,6 @@ impl Value {
             _ => Err(Error::UnexpectedSourceNode {
                 expected: "integer, string, boolean, float, list or empty",
                 actual: node.kind(),
-                location: node.start_position(),
             }),
         }
     }