Continue standard library implementation

dust-lang/src/abstract_tree/as.rs

@@ -56,7 +56,7 @@ impl AbstractNode for As {
             value
         } else {
             return Err(RuntimeError::ValidationFailure(
-                ValidationError::ExpectedExpression(expression_position),
+                ValidationError::ExpectedValueStatement(expression_position),
             ));
         };
         let r#type = self.constructor.construct(&context)?;

dust-lang/src/abstract_tree/function_call.rs

@@ -71,7 +71,7 @@ impl AbstractNode for FunctionCall {
             if let Some(r#type) = self.function_expression.expected_type(outer_context)? {
                 r#type
             } else {
-                return Err(ValidationError::ExpectedExpression(
+                return Err(ValidationError::ExpectedValueStatement(
                     self.function_expression.position(),
                 ));
             };
@@ -102,13 +102,14 @@ impl AbstractNode for FunctionCall {
                     for ((identifier, _), expression) in
                         parameters.iter().zip(arguments.into_iter())
                     {
-                        let r#type = if let Some(r#type) =
+                        let r#type =
-                            expression.expected_type(outer_context)?
+                            if let Some(r#type) = expression.expected_type(outer_context)? {
-                        {
+                                r#type
-                            r#type
+                            } else {
-                        } else {
+                                return Err(ValidationError::ExpectedValueStatement(
-                            return Err(ValidationError::ExpectedExpression(expression.position()));
+                                    expression.position(),
-                        };
+                                ));
+                            };
 
                         self.context.set_type(identifier.clone(), r#type)?;
                     }
@@ -157,7 +158,7 @@ impl AbstractNode for FunctionCall {
             value
         } else {
             return Err(RuntimeError::ValidationFailure(
-                ValidationError::ExpectedExpression(function_position),
+                ValidationError::ExpectedValueStatement(function_position),
             ));
         };
 
@@ -186,7 +187,7 @@ impl AbstractNode for FunctionCall {
                         value
                     } else {
                         return Err(RuntimeError::ValidationFailure(
-                            ValidationError::ExpectedValue(position),
+                            ValidationError::ExpectedValueStatement(position),
                         ));
                     };
 
@@ -236,7 +237,7 @@ impl AbstractNode for FunctionCall {
                         value
                     } else {
                         return Err(RuntimeError::ValidationFailure(
-                            ValidationError::ExpectedValue(position),
+                            ValidationError::ExpectedValueStatement(position),
                         ));
                     };
 
@@ -259,7 +260,7 @@ impl AbstractNode for FunctionCall {
 
     fn expected_type(&self, context: &Context) -> Result<Option<Type>, ValidationError> {
         let expression_type = self.function_expression.expected_type(context)?.ok_or(
-            ValidationError::ExpectedExpression(self.function_expression.position()),
+            ValidationError::ExpectedValueStatement(self.function_expression.position()),
         )?;
 
         let (type_parameters, return_type) = if let Type::Function {

dust-lang/src/abstract_tree/if_else.rs

@@ -60,7 +60,7 @@ impl AbstractNode for IfElse {
         let if_expression_type = if let Some(r#type) = self.if_expression.expected_type(context)? {
             r#type
         } else {
-            return Err(ValidationError::ExpectedExpression(
+            return Err(ValidationError::ExpectedValueStatement(
                 self.if_expression.position(),
             ));
         };
@@ -123,7 +123,7 @@ impl AbstractNode for IfElse {
             value
         } else {
             return Err(RuntimeError::ValidationFailure(
-                ValidationError::ExpectedExpression(if_position),
+                ValidationError::ExpectedValueStatement(if_position),
             ));
         };
 
@@ -140,7 +140,7 @@ impl AbstractNode for IfElse {
                         value
                     } else {
                         return Err(RuntimeError::ValidationFailure(
-                            ValidationError::ExpectedExpression(expression_position),
+                            ValidationError::ExpectedValueStatement(expression_position),
                         ));
                     };
 

dust-lang/src/abstract_tree/list_index.rs

@@ -37,14 +37,16 @@ impl AbstractNode for ListIndex {
         let collection_type = if let Some(r#type) = self.collection.expected_type(context)? {
             r#type
         } else {
-            return Err(ValidationError::ExpectedExpression(
+            return Err(ValidationError::ExpectedValueStatement(
                 self.collection.position(),
             ));
         };
         let index_type = if let Some(r#type) = self.index.expected_type(context)? {
             r#type
         } else {
-            return Err(ValidationError::ExpectedExpression(self.index.position()));
+            return Err(ValidationError::ExpectedValueStatement(
+                self.index.position(),
+            ));
         };
 
         match collection_type {
@@ -82,7 +84,7 @@ impl AbstractNode for ListIndex {
             value
         } else {
             return Err(RuntimeError::ValidationFailure(
-                ValidationError::ExpectedExpression(left_position),
+                ValidationError::ExpectedValueStatement(left_position),
             ));
         };
         let right_position = self.index.position();
@@ -91,7 +93,7 @@ impl AbstractNode for ListIndex {
             value
         } else {
             return Err(RuntimeError::ValidationFailure(
-                ValidationError::ExpectedExpression(right_position),
+                ValidationError::ExpectedValueStatement(right_position),
             ));
         };
 
@@ -119,7 +121,7 @@ impl AbstractNode for ListIndex {
         let left_type = if let Some(r#type) = self.collection.expected_type(_context)? {
             r#type
         } else {
-            return Err(ValidationError::ExpectedExpression(
+            return Err(ValidationError::ExpectedValueStatement(
                 self.collection.position(),
             ));
         };

dust-lang/src/abstract_tree/logic.rs

@@ -77,12 +77,12 @@ impl AbstractNode for Logic {
                 let left_type = if let Some(r#type) = left.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(left.position()));
+                    return Err(ValidationError::ExpectedValueStatement(left.position()));
                 };
                 let right_type = if let Some(r#type) = right.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(right.position()));
+                    return Err(ValidationError::ExpectedValueStatement(right.position()));
                 };
 
                 left_type
@@ -102,12 +102,12 @@ impl AbstractNode for Logic {
                 let left_type = if let Some(r#type) = left.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(left.position()));
+                    return Err(ValidationError::ExpectedValueStatement(left.position()));
                 };
                 let right_type = if let Some(r#type) = right.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(right.position()));
+                    return Err(ValidationError::ExpectedValueStatement(right.position()));
                 };
 
                 if let Type::Boolean = left_type {
@@ -134,7 +134,9 @@ impl AbstractNode for Logic {
                 let expression_type = if let Some(r#type) = expression.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(expression.position()));
+                    return Err(ValidationError::ExpectedValueStatement(
+                        expression.position(),
+                    ));
                 };
 
                 if let Type::Boolean = expression_type {
@@ -161,7 +163,7 @@ impl AbstractNode for Logic {
                 value
             } else {
                 return Err(RuntimeError::ValidationFailure(
-                    ValidationError::ExpectedExpression(expression_position),
+                    ValidationError::ExpectedValueStatement(expression_position),
                 ));
             };
 
@@ -175,7 +177,7 @@ impl AbstractNode for Logic {
                 value
             } else {
                 return Err(RuntimeError::ValidationFailure(
-                    ValidationError::ExpectedExpression(expression_position),
+                    ValidationError::ExpectedValueStatement(expression_position),
                 ));
             };
 

dust-lang/src/abstract_tree/map_index.rs

@@ -37,7 +37,7 @@ impl AbstractNode for MapIndex {
         let collection_type = if let Some(r#type) = self.collection.expected_type(context)? {
             r#type
         } else {
-            return Err(ValidationError::ExpectedExpression(
+            return Err(ValidationError::ExpectedValueStatement(
                 self.collection.position(),
             ));
         };
@@ -71,7 +71,7 @@ impl AbstractNode for MapIndex {
             value
         } else {
             return Err(RuntimeError::ValidationFailure(
-                ValidationError::ExpectedExpression(collection_position),
+                ValidationError::ExpectedValueStatement(collection_position),
             ));
         };
 
@@ -166,7 +166,7 @@ impl AbstractNode for MapIndex {
         let collection_type = if let Some(r#type) = self.collection.expected_type(context)? {
             r#type
         } else {
-            return Err(ValidationError::ExpectedExpression(
+            return Err(ValidationError::ExpectedValueStatement(
                 self.collection.position(),
             ));
         };

dust-lang/src/abstract_tree/math.rs

@@ -52,12 +52,12 @@ impl AbstractNode for Math {
                 let left_type = if let Some(r#type) = left.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(left.position()));
+                    return Err(ValidationError::ExpectedValueStatement(left.position()));
                 };
                 let right_type = if let Some(r#type) = right.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(right.position()));
+                    return Err(ValidationError::ExpectedValueStatement(right.position()));
                 };
 
                 if let Type::Integer | Type::Float | Type::String = left_type {
@@ -83,12 +83,12 @@ impl AbstractNode for Math {
                 let left_type = if let Some(r#type) = left.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(left.position()));
+                    return Err(ValidationError::ExpectedValueStatement(left.position()));
                 };
                 let right_type = if let Some(r#type) = right.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(right.position()));
+                    return Err(ValidationError::ExpectedValueStatement(right.position()));
                 };
 
                 if let Type::Integer | Type::Float = left_type {
@@ -116,7 +116,7 @@ impl AbstractNode for Math {
                     value
                 } else {
                     return Err(RuntimeError::ValidationFailure(
-                        ValidationError::ExpectedExpression(position),
+                        ValidationError::ExpectedValueStatement(position),
                     ));
                 };
 
@@ -341,12 +341,12 @@ impl AbstractNode for Math {
                 let left_type = if let Some(r#type) = left.expected_type(_context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(left.position()));
+                    return Err(ValidationError::ExpectedValueStatement(left.position()));
                 };
                 let right_type = if let Some(r#type) = right.expected_type(_context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(right.position()));
+                    return Err(ValidationError::ExpectedValueStatement(right.position()));
                 };
 
                 if let Type::Float = left_type {

dust-lang/src/abstract_tree/mod.rs

@@ -120,26 +120,6 @@ impl AbstractTree {
         AbstractTree(statements)
     }
 
-    pub(crate) fn define_types(&self, context: &Context) -> Result<(), ValidationError> {
-        for statement in &self.0 {
-            statement.define_types(context)?;
-        }
-
-        Ok(())
-    }
-
-    pub(crate) fn validate(
-        &self,
-        context: &Context,
-        manage_memory: bool,
-    ) -> Result<(), ValidationError> {
-        for statement in &self.0 {
-            statement.validate(context, manage_memory)?;
-        }
-
-        Ok(())
-    }
-
     pub fn run(
         self,
         context: &Context,
@@ -206,6 +186,42 @@ impl Index<usize> for AbstractTree {
     }
 }
 
+impl AbstractNode for AbstractTree {
+    fn define_types(&self, context: &Context) -> Result<(), ValidationError> {
+        for statement in &self.0 {
+            statement.define_types(context)?;
+        }
+
+        Ok(())
+    }
+
+    fn validate(&self, context: &Context, manage_memory: bool) -> Result<(), ValidationError> {
+        for statement in &self.0 {
+            statement.validate(context, manage_memory)?;
+        }
+
+        Ok(())
+    }
+
+    fn evaluate(
+        self,
+        context: &Context,
+        manage_memory: bool,
+    ) -> Result<Option<Evaluation>, RuntimeError> {
+        let mut previous = None;
+
+        for statement in self.0 {
+            previous = statement.evaluate(context, manage_memory)?;
+        }
+
+        Ok(previous)
+    }
+
+    fn expected_type(&self, context: &Context) -> Result<Option<Type>, ValidationError> {
+        self.0.last().unwrap().expected_type(context)
+    }
+}
+
 pub trait AbstractNode {
     fn define_types(&self, context: &Context) -> Result<(), ValidationError>;
 

dust-lang/src/abstract_tree/use.rs

@@ -1,4 +1,9 @@
-use std::{fmt::Display, fs::read_to_string, path::Path};
+use std::{
+    fmt::Display,
+    fs::read_to_string,
+    path::Path,
+    sync::{Arc, RwLock},
+};
 
 use chumsky::prelude::*;
 use serde::{Deserialize, Serialize};
@@ -12,43 +17,53 @@ use crate::{
     Type,
 };
 
-use super::{AbstractNode, Evaluation};
+use super::{AbstractNode, AbstractTree, Evaluation};
 
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
+#[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct Use {
     path: String,
+
+    #[serde(skip)]
+    abstract_tree: Arc<RwLock<Option<AbstractTree>>>,
 }
 
 impl Use {
     pub fn new(path: String) -> Self {
-        Self { path }
+        Self {
+            path,
+            abstract_tree: Arc::new(RwLock::new(None)),
+        }
     }
 }
 
 impl AbstractNode for Use {
-    fn define_types(&self, context: &Context) -> Result<(), ValidationError> {
+    fn define_types(&self, _context: &Context) -> Result<(), ValidationError> {
-        match self.path.as_str() {
+        let abstract_tree = match self.path.as_str() {
-            "std.io" => std_io_compiled().define_types(context),
+            "std.fs" => std_fs_compiled().clone(),
+            "std.json" => std_json_compiled().clone(),
+            "std.io" => std_io_compiled().clone(),
+            "std.thread" => std_thread_compiled().clone(),
             _ => {
                 if Path::new(&self.path).exists() {
-                    Ok(())
+                    todo!()
                 } else {
-                    Err(ValidationError::CannotUsePath(self.path.clone()))
+                    return Err(ValidationError::CannotUsePath(self.path.clone()));
                 }
             }
-        }
+        };
+
+        abstract_tree.define_types(_context)?;
+
+        *self.abstract_tree.write()? = Some(abstract_tree);
+
+        Ok(())
     }
 
     fn validate(&self, context: &Context, manage_memory: bool) -> Result<(), ValidationError> {
-        match self.path.as_str() {
+        if let Some(abstract_tree) = self.abstract_tree.read()?.as_ref() {
-            "std.io" => std_io_compiled().validate(context, manage_memory),
+            abstract_tree.validate(context, manage_memory)
-            _ => {
+        } else {
-                if Path::new(&self.path).exists() {
+            Err(ValidationError::Uninitialized)
-                    Ok(())
-                } else {
-                    Err(ValidationError::CannotUsePath(self.path.clone()))
-                }
-            }
         }
     }
 
@@ -57,39 +72,21 @@ impl AbstractNode for Use {
         context: &Context,
         manage_memory: bool,
     ) -> Result<Option<Evaluation>, RuntimeError> {
-        let abstact_tree = match self.path.as_str() {
+        if let Some(abstract_tree) = self.abstract_tree.read()?.as_ref() {
-            "std.fs" => std_fs_compiled().clone(),
+            abstract_tree.clone().evaluate(context, manage_memory)
-            "std.io" => std_io_compiled().clone(),
+        } else {
-            "std.json" => std_json_compiled().clone(),
+            Err(RuntimeError::ValidationFailure(
-            "std.thread" => std_thread_compiled().clone(),
+                ValidationError::Uninitialized,
-            path => {
+            ))
-                let file_contents = read_to_string(path)?;
+        }
-                let tokens = lex(&file_contents).map_err(|errors| RuntimeError::Use(errors))?;
-                let abstract_tree = parser(false)
-                    .parse(tokens.spanned((tokens.len()..tokens.len()).into()))
-                    .into_result()
-                    .map_err(|errors| {
-                        RuntimeError::Use(
-                            errors
-                                .into_iter()
-                                .map(|error| DustError::from(error))
-                                .collect::<Vec<DustError>>(),
-                        )
-                    })?;
-
-                abstract_tree
-            }
-        };
-
-        abstact_tree
-            .run(context, manage_memory)
-            .map_err(|errors| RuntimeError::Use(errors))?;
-
-        Ok(None)
     }
 
     fn expected_type(&self, context: &Context) -> Result<Option<Type>, ValidationError> {
-        todo!()
+        if let Some(abstract_tree) = self.abstract_tree.read()?.as_ref() {
+            abstract_tree.expected_type(context)
+        } else {
+            Err(ValidationError::Uninitialized)
+        }
     }
 }
 
@@ -98,3 +95,23 @@ impl Display for Use {
         todo!()
     }
 }
+
+impl Eq for Use {}
+
+impl PartialEq for Use {
+    fn eq(&self, other: &Self) -> bool {
+        todo!()
+    }
+}
+
+impl PartialOrd for Use {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        todo!()
+    }
+}
+
+impl Ord for Use {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        todo!()
+    }
+}

dust-lang/src/abstract_tree/value_node.rs

@@ -127,14 +127,16 @@ impl AbstractNode for ValueNode {
             let first_item_type = if let Some(r#type) = first_item.expected_type(context)? {
                 r#type
             } else {
-                return Err(ValidationError::ExpectedExpression(first_item.position()));
+                return Err(ValidationError::ExpectedValueStatement(
+                    first_item.position(),
+                ));
             };
 
             for item in items {
                 let item_type = if let Some(r#type) = item.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(item.position()));
+                    return Err(ValidationError::ExpectedValueStatement(item.position()));
                 };
 
                 first_item_type.check(&item_type).map_err(|conflict| {
@@ -178,7 +180,9 @@ impl AbstractNode for ValueNode {
                     let actual_type = if let Some(r#type) = expression.expected_type(context)? {
                         r#type
                     } else {
-                        return Err(ValidationError::ExpectedExpression(expression.position()));
+                        return Err(ValidationError::ExpectedValueStatement(
+                            expression.position(),
+                        ));
                     };
                     let expected_type = constructor.clone().construct(&context)?;
 
@@ -213,9 +217,13 @@ impl AbstractNode for ValueNode {
                         ),
                         r#type,
                     ),
-                    (None, Some(_)) => return Err(ValidationError::ExpectedValue(body.position)),
+                    (None, Some(_)) => {
+                        return Err(ValidationError::ExpectedNonValueStatement(body.position))
+                    }
                     (Some(constructor), None) => {
-                        return Err(ValidationError::ExpectedExpression(constructor.position()))
+                        return Err(ValidationError::ExpectedValueStatement(
+                            constructor.position(),
+                        ))
                     }
                     (None, None) => return Ok(()),
                 };
@@ -252,7 +260,9 @@ impl AbstractNode for ValueNode {
                     let actual_type = if let Some(r#type) = expression.expected_type(context)? {
                         r#type
                     } else {
-                        return Err(ValidationError::ExpectedExpression(expression.position()));
+                        return Err(ValidationError::ExpectedValueStatement(
+                            expression.position(),
+                        ));
                     };
 
                     expected_type.check(&actual_type).map_err(|conflict| {
@@ -292,7 +302,7 @@ impl AbstractNode for ValueNode {
                             values.push(value);
                         } else {
                             return Err(RuntimeError::ValidationFailure(
-                                ValidationError::ExpectedExpression(position),
+                                ValidationError::ExpectedValueStatement(position),
                             ));
                         }
                     }
@@ -315,7 +325,7 @@ impl AbstractNode for ValueNode {
                         value
                     } else {
                         return Err(RuntimeError::ValidationFailure(
-                            ValidationError::ExpectedExpression(position),
+                            ValidationError::ExpectedValueStatement(position),
                         ));
                     };
 
@@ -334,7 +344,7 @@ impl AbstractNode for ValueNode {
                         value
                     } else {
                         return Err(RuntimeError::ValidationFailure(
-                            ValidationError::ExpectedExpression(position),
+                            ValidationError::ExpectedValueStatement(position),
                         ));
                     };
 
@@ -387,7 +397,7 @@ impl AbstractNode for ValueNode {
                         value
                     } else {
                         return Err(RuntimeError::ValidationFailure(
-                            ValidationError::ExpectedExpression(position),
+                            ValidationError::ExpectedValueStatement(position),
                         ));
                     };
 
@@ -422,7 +432,9 @@ impl AbstractNode for ValueNode {
                 let item_type = if let Some(r#type) = first_item.expected_type(context)? {
                     r#type
                 } else {
-                    return Err(ValidationError::ExpectedExpression(first_item.position()));
+                    return Err(ValidationError::ExpectedValueStatement(
+                        first_item.position(),
+                    ));
                 };
 
                 Type::List {
@@ -498,7 +510,9 @@ impl AbstractNode for ValueNode {
                     let r#type = if let Some(r#type) = expression.expected_type(context)? {
                         r#type
                     } else {
-                        return Err(ValidationError::ExpectedExpression(expression.position()));
+                        return Err(ValidationError::ExpectedValueStatement(
+                            expression.position(),
+                        ));
                     };
 
                     types.push((

dust-lang/src/abstract_tree/while.rs

@@ -63,7 +63,7 @@ impl AbstractNode for While {
                 Ok(value)
             } else {
                 Err(RuntimeError::ValidationFailure(
-                    ValidationError::ExpectedExpression(expression_position),
+                    ValidationError::ExpectedValueStatement(expression_position),
                 ))
             }
         };

dust-lang/src/context.rs

@@ -7,6 +7,7 @@ use crate::{
     abstract_tree::Type,
     error::{PoisonError, ValidationError},
     identifier::Identifier,
+    standard_library::core_context,
     value::ValueInner,
     Value,
 };
@@ -34,6 +35,16 @@ impl Context {
         }
     }
 
+    pub fn new_with_std_core(parent: Option<Context>) -> Result<Self, PoisonError> {
+        let new = Context::with_variables_from(core_context())?;
+
+        if let Some(context) = parent {
+            new.set_parent(context)?;
+        }
+
+        Ok(new)
+    }
+
     pub fn with_variables_from(other: &Context) -> Result<Self, PoisonError> {
         let variables = other.data.read()?.variables.clone();
 

dust-lang/src/error.rs

@@ -104,6 +104,8 @@ impl PartialEq for RuntimeError {
 
 #[derive(Debug, PartialEq)]
 pub enum ValidationError {
+    /// A node needs to be initialized before it can be validated.
+    Uninitialized,
     BuiltInFunctionFailure(&'static str),
     CannotAssignToNone(SourcePosition),
     CannotIndex {
@@ -138,12 +140,12 @@ pub enum ValidationError {
         actual: Type,
         position: SourcePosition,
     },
-    ExpectedValue(SourcePosition),
     FullTypeNotKnown {
         identifier: Identifier,
         position: SourcePosition,
     },
-    ExpectedExpression(SourcePosition),
+    ExpectedValueStatement(SourcePosition),
+    ExpectedNonValueStatement(SourcePosition),
     RwLockPoison(PoisonError),
     TypeCheck {
         /// The mismatch that caused the error.

dust-lang/src/lib.rs

@@ -341,9 +341,13 @@ impl InterpreterError {
                             .with_message(format!("This has type {}.", index_type.fg(type_color),)),
                         ])
                     }
-                    ValidationError::ExpectedExpression(position) => builder.add_label(
+                    ValidationError::ExpectedValueStatement(position) => builder.add_label(
                         Label::new((self.source_id.clone(), position.0..position.1))
-                            .with_message("Expected a statement that ends in an expression."),
+                            .with_message("Expected a statement that yields a value."),
+                    ),
+                    ValidationError::ExpectedNonValueStatement(position) => builder.add_label(
+                        Label::new((self.source_id.clone(), position.0..position.1))
+                            .with_message("Expected a statement that does not yield a value."),
                     ),
                     ValidationError::ExpectedFunction { actual, position } => builder.add_label(
                         Label::new((self.source_id.clone(), position.0..position.1)).with_message(
@@ -353,7 +357,6 @@ impl InterpreterError {
                             ),
                         ),
                     ),
-                    ValidationError::ExpectedValue(_) => todo!(),
                     ValidationError::FieldNotFound {
                         identifier,
                         position,
@@ -418,6 +421,7 @@ impl InterpreterError {
                     ValidationError::BuiltInFunctionFailure(reason) => builder
                         .add_label(Label::new((self.source_id.clone(), 0..0)).with_message(reason)),
                     ValidationError::CannotUsePath(_) => todo!(),
+                    ValidationError::Uninitialized => todo!(),
                 }
             }
 

dust-lang/src/standard_library.rs

@@ -1,6 +1,11 @@
 use std::sync::{Arc, OnceLock};
 
-use crate::{abstract_tree::AbstractTree, lexer::lex, parser};
+use crate::{
+    abstract_tree::{AbstractNode, AbstractTree},
+    context::Context,
+    lexer::lex,
+    parser,
+};
 use chumsky::prelude::*;
 
 pub fn std_full_compiled() -> [AbstractTree; 5] {
@@ -19,6 +24,27 @@ pub const STD_IO: &str = include_str!("../../std/io.ds");
 pub const STD_JSON: &str = include_str!("../../std/json.ds");
 pub const STD_THREAD: &str = include_str!("../../std/thread.ds");
 
+static CORE_CONTEXT: OnceLock<Context> = OnceLock::new();
+
+pub fn core_context<'a>() -> &'a Context {
+    CORE_CONTEXT.get_or_init(|| {
+        let context = Context::new(None);
+        let std_core = std_core_compiled().clone();
+
+        std_core
+            .define_types(&context)
+            .expect("Failed to define types for std.core");
+        std_core
+            .validate(&context, true)
+            .expect("Failed to validate std.core");
+        std_core
+            .evaluate(&context, true)
+            .expect("Failed to evaluate std.core");
+
+        context
+    })
+}
+
 static CORE_SOURCE: OnceLock<(Arc<str>, Arc<str>)> = OnceLock::new();
 
 pub fn core_source<'a>() -> &'a (Arc<str>, Arc<str>) {
@@ -42,11 +68,11 @@ static STD_CORE_COMPILED: OnceLock<AbstractTree> = OnceLock::new();
 
 pub fn std_core_compiled<'a>() -> &'a AbstractTree {
     STD_CORE_COMPILED.get_or_init(|| {
-        let tokens = lex(STD_CORE).expect("Failed to lex.");
+        let tokens = lex(STD_CORE).expect("Failed to lex");
         let abstract_tree = parser(true)
             .parse(tokens.spanned((tokens.len()..tokens.len()).into()))
             .into_result()
-            .expect("Failed to parse.");
+            .expect("Failed to parse");
 
         abstract_tree
     })
@@ -56,11 +82,11 @@ static STD_FS_COMPILED: OnceLock<AbstractTree> = OnceLock::new();
 
 pub fn std_fs_compiled<'a>() -> &'a AbstractTree {
     STD_FS_COMPILED.get_or_init(|| {
-        let tokens = lex(STD_FS).expect("Failed to lex.");
+        let tokens = lex(STD_FS).expect("Failed to lex");
         let abstract_tree = parser(true)
             .parse(tokens.spanned((tokens.len()..tokens.len()).into()))
             .into_result()
-            .expect("Failed to parse.");
+            .expect("Failed to parse");
 
         abstract_tree
     })
@@ -70,11 +96,11 @@ static STD_IO_COMPILED: OnceLock<AbstractTree> = OnceLock::new();
 
 pub fn std_io_compiled<'a>() -> &'a AbstractTree {
     STD_IO_COMPILED.get_or_init(|| {
-        let tokens = lex(STD_IO).expect("Failed to lex.");
+        let tokens = lex(STD_IO).expect("Failed to lex");
         let abstract_tree = parser(true)
             .parse(tokens.spanned((tokens.len()..tokens.len()).into()))
             .into_result()
-            .expect("Failed to parse.");
+            .expect("Failed to parse");
 
         abstract_tree
     })
@@ -84,11 +110,11 @@ static STD_JSON_COMPILED: OnceLock<AbstractTree> = OnceLock::new();
 
 pub fn std_json_compiled<'a>() -> &'a AbstractTree {
     STD_JSON_COMPILED.get_or_init(|| {
-        let tokens = lex(STD_JSON).expect("Failed to lex.");
+        let tokens = lex(STD_JSON).expect("Failed to lex");
         let abstract_tree = parser(true)
             .parse(tokens.spanned((tokens.len()..tokens.len()).into()))
             .into_result()
-            .expect("Failed to parse.");
+            .expect("Failed to parse");
 
         abstract_tree
     })
@@ -98,11 +124,11 @@ static STD_THREAD_COMPILED: OnceLock<AbstractTree> = OnceLock::new();
 
 pub fn std_thread_compiled<'a>() -> &'a AbstractTree {
     STD_THREAD_COMPILED.get_or_init(|| {
-        let tokens = lex(STD_THREAD).expect("Failed to lex.");
+        let tokens = lex(STD_THREAD).expect("Failed to lex");
         let abstract_tree = parser(true)
             .parse(tokens.spanned((tokens.len()..tokens.len()).into()))
             .into_result()
-            .expect("Failed to parse.");
+            .expect("Failed to parse");
 
         abstract_tree
     })

dust-shell/src/main.rs

@@ -56,7 +56,7 @@ fn main() {
         .init();
 
     let args = Args::parse();
-    let context = Context::new(None);
+    let context = Context::new_with_std_core(None).unwrap();
     let interpreter = Interpreter::new(context.clone());
 
     let (source_id, source): (Arc<str>, Arc<str>) = if let Some(path) = args.path {