Improve expression implementation

src/abstract_tree/expression.rs

@@ -18,8 +18,8 @@ impl AbstractTree for Expression {
     fn from_syntax_node(source: &str, node: Node) -> Result<Self> {
         debug_assert_eq!("expression", node.kind());
 
-        let child = node.child(0).unwrap();
-
+        for index in 0..node.child_count() {
+            let child = node.child(index).unwrap();
             let expression = match child.kind() {
                 "value" => Expression::Value(ValueNode::from_syntax_node(source, child)?),
                 "identifier" => Self::Identifier(Identifier::from_syntax_node(source, child)?),
@@ -28,18 +28,21 @@ impl AbstractTree for Expression {
                 "function_call" => {
                     Expression::FunctionCall(FunctionCall::from_syntax_node(source, child)?)
                 }
-            _ => {
-                return Err(Error::UnexpectedSyntaxNode {
+                _ => continue,
+            };
+
+            return Ok(expression);
+        }
+
+        let child = node.child(0).unwrap();
+
+        Err(Error::UnexpectedSyntaxNode {
             expected: "value, identifier, math or function_call",
             actual: child.kind(),
             location: child.start_position(),
             relevant_source: source[child.byte_range()].to_string(),
         })
     }
-        };
-
-        Ok(expression)
-    }
 
     fn run(&self, source: &str, context: &mut VariableMap) -> Result<Value> {
         match self {

src/abstract_tree/math.rs

@@ -43,31 +43,17 @@ impl AbstractTree for Math {
     }
 
     fn run(&self, source: &str, context: &mut VariableMap) -> Result<Value> {
-        match self.operator {
-            MathOperator::Add | MathOperator::Subtract | MathOperator::Multiply => {
-                let left_value = self.left.run(source, context)?.as_int()?;
-                let right_value = self.right.run(source, context)?.as_int()?;
-                let outcome = match &self.operator {
-                    MathOperator::Add => left_value + right_value,
-                    MathOperator::Subtract => left_value - right_value,
-                    MathOperator::Multiply => left_value * right_value,
-                    _ => panic!("Unreachable"),
-                };
+        let left = self.left.run(source, context)?;
+        let right = self.right.run(source, context)?;
+        let value = match self.operator {
+            MathOperator::Add => left + right,
+            MathOperator::Subtract => left - right,
+            MathOperator::Multiply => left * right,
+            MathOperator::Divide => left / right,
+            MathOperator::Modulo => left % right,
+        }?;
 
-                Ok(Value::Integer(outcome))
-            }
-            MathOperator::Divide | MathOperator::Modulo => {
-                let left_value = self.left.run(source, context)?.as_number()?;
-                let right_value = self.right.run(source, context)?.as_number()?;
-                let outcome = match self.operator {
-                    MathOperator::Divide => left_value / right_value,
-                    MathOperator::Modulo => left_value % right_value,
-                    _ => panic!("Unreachable"),
-                };
-
-                Ok(Value::Float(outcome))
-            }
-        }
+        Ok(value)
     }
 }
 

src/error.rs

@@ -277,7 +277,10 @@ impl fmt::Display for Error {
                 actual,
                 location,
                 relevant_source,
-            } => todo!(),
+            } => write!(
+                f,
+                "Expected syntax node {expected}, but got {actual} at {location}. Code: {relevant_source} ",
+            ),
             ExpectedChildNode { empty_node_sexp } => todo!(),
             WrongColumnAmount { expected, actual } => todo!(),
             ToolFailure(_) => todo!(),

src/value/mod.rs

@@ -16,7 +16,7 @@ use std::{
     convert::TryFrom,
     fmt::{self, Display, Formatter},
     marker::PhantomData,
-    ops::{Add, AddAssign, Sub, SubAssign},
+    ops::{Add, AddAssign, Div, Mul, Rem, Sub, SubAssign},
 };
 
 pub mod function;
@@ -260,6 +260,56 @@ impl Sub for Value {
     }
 }
 
+impl Mul for Value {
+    type Output = Result<Self>;
+
+    fn mul(self, other: Self) -> Self::Output {
+        if self.is_integer() && other.is_integer() {
+            let left = self.as_int().unwrap();
+            let right = other.as_int().unwrap();
+            let value = Value::Integer(left.saturating_mul(right));
+
+            Ok(value)
+        } else {
+            let left = self.as_number()?;
+            let right = other.as_number()?;
+            let value = Value::Float(left * right);
+
+            Ok(value)
+        }
+    }
+}
+
+impl Div for Value {
+    type Output = Result<Self>;
+
+    fn div(self, other: Self) -> Self::Output {
+        let left = self.as_number()?;
+        let right = other.as_number()?;
+        let result = left / right;
+
+        let value = if result % 2.0 == 0.0 {
+            Value::Integer(result as i64)
+        } else {
+            Value::Float(result)
+        };
+
+        Ok(value)
+    }
+}
+
+impl Rem for Value {
+    type Output = Result<Self>;
+
+    fn rem(self, other: Self) -> Self::Output {
+        let left = self.as_int()?;
+        let right = other.as_int()?;
+        let result = left % right;
+
+        Ok(Value::Integer(result))
+    }
+}
+
 impl AddAssign for Value {
     fn add_assign(&mut self, other: Self) {
         match (self, other) {