Add anaylsis to check for valid fields and indexes

dust-lang/src/abstract_tree.rs

@@ -147,7 +147,7 @@ impl Statement {
                 BinaryOperator::ListIndex => {
                     let left_type = left.inner.expected_type(context)?;
 
-                    if let Type::List { item_type } = left_type {
+                    if let Type::List { item_type, .. } = left_type {
                         Some(*item_type)
                     } else {
                         None
@@ -167,6 +167,7 @@ impl Statement {
 
                 Some(Type::List {
                     item_type: Box::new(item_type),
+                    length: nodes.len(),
                 })
             }
             Statement::Map(nodes) => {

dust-lang/src/analyzer.rs

@@ -11,7 +11,7 @@ use std::{
 
 use crate::{
     abstract_tree::{BinaryOperator, UnaryOperator},
-    parse, AbstractSyntaxTree, Context, DustError, Node, Span, Statement, Type,
+    parse, AbstractSyntaxTree, Context, DustError, Identifier, Node, Span, Statement, Type,
 };
 
 /// Analyzes the abstract syntax tree for errors.
@@ -105,8 +105,11 @@ impl<'a> Analyzer<'a> {
                         self.analyze_statement(right)?;
                     }
 
-                    if let Some(Type::Map { .. }) = left.inner.expected_type(self.context) {
+                    let left_type = left.inner.expected_type(self.context);
-                        if let Some(Type::String) = right.inner.expected_type(self.context) {
+                    let right_type = right.inner.expected_type(self.context);
+
+                    if let Some(Type::Map { .. }) = left_type {
+                        if let Some(Type::String) = right_type {
                             // Allow indexing maps with strings
                         } else if let Statement::Identifier(_) = right.inner {
                             // Allow indexing maps with identifiers
@@ -121,6 +124,31 @@ impl<'a> Analyzer<'a> {
                         });
                     }
 
+                    // If the accessor is an identifier, check if it is a valid field
+                    if let Statement::Identifier(identifier) = &right.inner {
+                        if let Some(Type::Map(fields)) = &left_type {
+                            if !fields.contains_key(identifier) {
+                                return Err(AnalyzerError::UndefinedField {
+                                    identifier: right.as_ref().clone(),
+                                    map: left.as_ref().clone(),
+                                });
+                            }
+                        }
+                    }
+                    // If the accessor is a constant, check if it is a valid field
+                    if let Statement::Constant(value) = &right.inner {
+                        if let Some(field_name) = value.as_string() {
+                            if let Some(Type::Map(fields)) = left_type {
+                                if !fields.contains_key(&Identifier::new(field_name)) {
+                                    return Err(AnalyzerError::UndefinedField {
+                                        identifier: right.as_ref().clone(),
+                                        map: left.as_ref().clone(),
+                                    });
+                                }
+                            }
+                        }
+                    }
+
                     return Ok(());
                 }
 
@@ -128,7 +156,8 @@ impl<'a> Analyzer<'a> {
                     self.analyze_statement(left)?;
                     self.analyze_statement(right)?;
 
-                    if let Some(Type::List { .. }) = left.inner.expected_type(self.context) {
+                    if let Some(Type::List { length, .. }) = left.inner.expected_type(self.context)
+                    {
                         let index_type = right.inner.expected_type(self.context);
 
                         if let Some(Type::Integer | Type::Range) = index_type {
@@ -138,6 +167,22 @@ impl<'a> Analyzer<'a> {
                                 actual: right.as_ref().clone(),
                             });
                         }
+
+                        // If the index is a constant, check if it is out of bounds
+                        if let Statement::Constant(value) = &right.inner {
+                            if let Some(index_value) = value.as_integer() {
+                                let index_value = index_value as usize;
+
+                                if index_value >= length {
+                                    return Err(AnalyzerError::IndexOutOfBounds {
+                                        list: left.as_ref().clone(),
+                                        index: right.as_ref().clone(),
+                                        index_value,
+                                        length,
+                                    });
+                                }
+                            }
+                        }
                     } else {
                         return Err(AnalyzerError::ExpectedList {
                             actual: left.as_ref().clone(),
@@ -459,6 +504,10 @@ pub enum AnalyzerError {
     UndefinedVariable {
         identifier: Node<Statement>,
     },
+    UndefinedField {
+        identifier: Node<Statement>,
+        map: Node<Statement>,
+    },
     UnexpectedIdentifier {
         identifier: Node<Statement>,
     },
@@ -484,6 +533,7 @@ impl AnalyzerError {
             AnalyzerError::TypeConflict {
                 actual_statement, ..
             } => actual_statement.position,
+            AnalyzerError::UndefinedField { identifier, .. } => identifier.position,
             AnalyzerError::UndefinedVariable { identifier } => identifier.position,
             AnalyzerError::UnexpectedIdentifier { identifier } => identifier.position,
             AnalyzerError::UnexectedString { actual } => actual.position,
@@ -518,9 +568,9 @@ impl Display for AnalyzerError {
             } => write!(f, "Expected {} value arguments, found {}", expected, actual),
             AnalyzerError::IndexOutOfBounds {
                 list,
-                index,
                 index_value,
                 length,
+                ..
             } => write!(
                 f,
                 "Index {} out of bounds for list {} with length {}",
@@ -537,6 +587,9 @@ impl Display for AnalyzerError {
                     expected, actual_statement, actual_type
                 )
             }
+            AnalyzerError::UndefinedField { identifier, map } => {
+                write!(f, "Undefined field {} in map {}", identifier, map)
+            }
             AnalyzerError::UndefinedVariable { identifier } => {
                 write!(f, "Undefined variable {}", identifier)
             }
@@ -582,14 +635,43 @@ mod tests {
     }
 
     #[test]
-    fn nonexistant_field() {
+    fn nonexistant_field_identifier() {
         let source = "{ x = 1 }.y";
 
         assert_eq!(
             analyze(source),
             Err(DustError::AnalyzerError {
-                analyzer_error: AnalyzerError::UndefinedVariable {
+                analyzer_error: AnalyzerError::UndefinedField {
                     identifier: Node::new(Statement::Identifier(Identifier::new("y")), (10, 11)),
+                    map: Node::new(
+                        Statement::Map(vec![(
+                            Node::new(Statement::Identifier(Identifier::new("x")), (2, 3)),
+                            Node::new(Statement::Constant(Value::integer(1)), (6, 7))
+                        )]),
+                        (0, 9)
+                    )
+                },
+                source
+            })
+        );
+    }
+
+    #[test]
+    fn nonexistant_field_string() {
+        let source = "{ x = 1 }.'y'";
+
+        assert_eq!(
+            analyze(source),
+            Err(DustError::AnalyzerError {
+                analyzer_error: AnalyzerError::UndefinedField {
+                    identifier: Node::new(Statement::Constant(Value::string("y")), (10, 13)),
+                    map: Node::new(
+                        Statement::Map(vec![(
+                            Node::new(Statement::Identifier(Identifier::new("x")), (2, 3)),
+                            Node::new(Statement::Constant(Value::integer(1)), (6, 7))
+                        )]),
+                        (0, 9)
+                    )
                 },
                 source
             })

dust-lang/src/built_in_function.rs

@@ -47,7 +47,7 @@ impl BuiltInFunction {
             BuiltInFunction::Length => {
                 vec![(
                     "value".into(),
-                    Type::List {
+                    Type::ListOf {
                         item_type: Box::new(Type::Any),
                     },
                 )]

dust-lang/src/type.rs

@@ -50,6 +50,10 @@ pub enum Type {
     Integer,
     List {
         item_type: Box<Type>,
+        length: usize,
+    },
+    ListOf {
+        item_type: Box<Type>,
     },
     Map(BTreeMap<Identifier, Type>),
     Number,
@@ -139,9 +143,35 @@ impl Type {
             (
                 Type::List {
                     item_type: left_type,
+                    length: left_length,
                 },
                 Type::List {
                     item_type: right_type,
+                    length: right_length,
+                },
+            ) => {
+                if left_length != right_length {
+                    return Err(TypeConflict {
+                        actual: other.clone(),
+                        expected: self.clone(),
+                    });
+                }
+
+                if left_type.check(right_type).is_err() {
+                    return Err(TypeConflict {
+                        actual: other.clone(),
+                        expected: self.clone(),
+                    });
+                }
+
+                return Ok(());
+            }
+            (
+                Type::ListOf {
+                    item_type: left_type,
+                },
+                Type::ListOf {
+                    item_type: right_type,
                 },
             ) => {
                 if left_type.check(right_type).is_err() {
@@ -150,9 +180,37 @@ impl Type {
                         expected: self.clone(),
                     });
                 }
-
+            }
+            (
+                Type::List {
+                    item_type: list_item_type,
+                    ..
+                },
+                Type::ListOf {
+                    item_type: list_of_item_type,
+                },
+            )
+            | (
+                Type::ListOf {
+                    item_type: list_of_item_type,
+                },
+                Type::List {
+                    item_type: list_item_type,
+                    ..
+                },
+            ) => {
+                // TODO: This is a hack, remove it.
+                if let Type::Any = **list_of_item_type {
                     return Ok(());
                 }
+
+                if list_item_type.check(list_of_item_type).is_err() {
+                    return Err(TypeConflict {
+                        actual: other.clone(),
+                        expected: self.clone(),
+                    });
+                }
+            }
             (
                 Type::Function {
                     type_parameters: left_type_parameters,
@@ -248,7 +306,8 @@ impl Display for Type {
                 }
             }
             Type::Integer => write!(f, "int"),
-            Type::List { item_type } => write!(f, "[{item_type}]"),
+            Type::List { item_type, length } => write!(f, "[{item_type}; {length}]"),
+            Type::ListOf { item_type } => write!(f, "list_of({item_type})"),
             Type::Map(map) => {
                 write!(f, "{{ ")?;
 
@@ -316,9 +375,11 @@ mod tests {
         assert_eq!(
             Type::List {
                 item_type: Box::new(Type::Boolean),
+                length: 42
             }
             .check(&Type::List {
                 item_type: Box::new(Type::Boolean),
+                length: 42
             }),
             Ok(())
         );
@@ -360,6 +421,7 @@ mod tests {
             Type::Integer,
             Type::List {
                 item_type: Box::new(Type::Integer),
+                length: 42,
             },
             Type::Map(BTreeMap::new()),
             Type::Range,

dust-lang/src/value.rs

@@ -679,6 +679,7 @@ impl ValueInner {
 
                 Type::List {
                     item_type: Box::new(item_type),
+                    length: values.len(),
                 }
             }
             ValueInner::Map(value_map) => {