Add a parser test; Pass VM test

dust-lang/src/ast/expression.rs

@@ -6,7 +6,7 @@ use std::{
 
 use serde::{Deserialize, Serialize};
 
-use crate::{Context, FunctionType, Identifier, RangeableType, StructType, Type};
+use crate::{BuiltInFunction, Context, FunctionType, Identifier, RangeableType, StructType, Type};
 
 use super::{Node, Span, Statement};
 
@@ -338,6 +338,9 @@ impl Expression {
                 }
             }
             Expression::Literal(literal_expression) => match literal_expression.inner.as_ref() {
+                LiteralExpression::BuiltInFunction(built_in_function) => {
+                    built_in_function.return_type()
+                }
                 LiteralExpression::Primitive(primitive_value) => match primitive_value {
                     PrimitiveValueExpression::Boolean(_) => Some(Type::Boolean),
                     PrimitiveValueExpression::Character(_) => Some(Type::Character),
@@ -682,6 +685,7 @@ impl From<char> for LiteralExpression {
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum LiteralExpression {
+    BuiltInFunction(BuiltInFunction),
     Primitive(PrimitiveValueExpression),
     String(String),
 }
@@ -689,6 +693,9 @@ pub enum LiteralExpression {
 impl Display for LiteralExpression {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
+            LiteralExpression::BuiltInFunction(built_in_function) => {
+                write!(f, "{built_in_function}")
+            }
             LiteralExpression::Primitive(primitive) => {
                 write!(f, "{primitive}")
             }
@@ -708,6 +715,11 @@ impl PartialOrd for LiteralExpression {
 impl Ord for LiteralExpression {
     fn cmp(&self, other: &Self) -> Ordering {
         match (self, other) {
+            (
+                LiteralExpression::BuiltInFunction(left),
+                LiteralExpression::BuiltInFunction(right),
+            ) => left.cmp(right),
+            (LiteralExpression::BuiltInFunction(_), _) => Ordering::Greater,
             (LiteralExpression::Primitive(left), LiteralExpression::Primitive(right)) => {
                 left.cmp(right)
             }

dust-lang/src/built_in_function.rs

@@ -13,7 +13,7 @@ use crate::{Identifier, Type, Value};
 #[derive(Debug, Clone, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
 pub enum BuiltInFunction {
     // String tools
-    ToString,
+    ToString { argument: Box<Value> },
 
     // Integer and float tools
     IsEven,
@@ -34,26 +34,46 @@ impl BuiltInFunction {
             BuiltInFunction::IsOdd => "is_odd",
             BuiltInFunction::Length => "length",
             BuiltInFunction::ReadLine => "read_line",
-            BuiltInFunction::ToString => "to_string",
+            BuiltInFunction::ToString { .. } => "to_string",
             BuiltInFunction::WriteLine => "write_line",
         }
     }
 
-    pub fn value_parameters(&self) -> Vec<(Identifier, Type)> {
+    pub fn type_parameters(&self) -> Option<Vec<Identifier>> {
         match self {
-            BuiltInFunction::ToString => vec![("value".into(), Type::Any)],
+            BuiltInFunction::ToString { .. } => None,
-            BuiltInFunction::IsEven => vec![("value".into(), Type::Number)],
+            BuiltInFunction::IsEven => None,
-            BuiltInFunction::IsOdd => vec![("value".into(), Type::Number)],
+            BuiltInFunction::IsOdd => None,
-            BuiltInFunction::Length => {
+            BuiltInFunction::Length => None,
-                vec![(
+            BuiltInFunction::ReadLine => None,
+            BuiltInFunction::WriteLine => None,
+        }
+    }
+
+    pub fn value_parameters(&self) -> Option<Vec<(Identifier, Type)>> {
+        match self {
+            BuiltInFunction::ToString { .. } => Some(vec![("value".into(), Type::Any)]),
+            BuiltInFunction::IsEven => Some(vec![("value".into(), Type::Number)]),
+            BuiltInFunction::IsOdd => Some(vec![("value".into(), Type::Number)]),
+            BuiltInFunction::Length => Some(vec![(
                 "value".into(),
                 Type::ListOf {
                     item_type: Box::new(Type::Any),
                 },
-                )]
+            )]),
+            BuiltInFunction::ReadLine => None,
+            BuiltInFunction::WriteLine => Some(vec![("output".into(), Type::Any)]),
         }
-            BuiltInFunction::ReadLine => vec![],
+    }
-            BuiltInFunction::WriteLine => vec![("output".into(), Type::Any)],
+
+    pub fn return_type(&self) -> Option<Type> {
+        match self {
+            BuiltInFunction::ToString { .. } => Some(Type::String),
+            BuiltInFunction::IsEven => Some(Type::Boolean),
+            BuiltInFunction::IsOdd => Some(Type::Boolean),
+            BuiltInFunction::Length => Some(Type::Number),
+            BuiltInFunction::ReadLine => Some(Type::String),
+            BuiltInFunction::WriteLine => None,
         }
     }
 
@@ -63,17 +83,7 @@ impl BuiltInFunction {
         value_arguments: Option<Vec<Value>>,
     ) -> Result<Option<Value>, BuiltInFunctionError> {
         match self {
-            BuiltInFunction::ToString => {
+            BuiltInFunction::ToString { argument } => Ok(Some(Value::string(argument))),
-                if let Some(value_arguments) = value_arguments {
-                    if value_arguments.len() == 1 {
-                        Ok(Some(Value::string(value_arguments[0].to_string())))
-                    } else {
-                        Err(BuiltInFunctionError::WrongNumberOfValueArguments)
-                    }
-                } else {
-                    Err(BuiltInFunctionError::WrongNumberOfValueArguments)
-                }
-            }
             BuiltInFunction::IsEven => {
                 if let Some(value_arguments) = value_arguments {
                     if value_arguments.len() == 1 {
@@ -145,17 +155,6 @@ impl BuiltInFunction {
             }
         }
     }
-
-    pub fn expected_return_type(&self) -> Option<Type> {
-        match self {
-            BuiltInFunction::ToString => Some(Type::String),
-            BuiltInFunction::IsEven => Some(Type::Boolean),
-            BuiltInFunction::IsOdd => Some(Type::Boolean),
-            BuiltInFunction::Length => Some(Type::Integer),
-            BuiltInFunction::ReadLine => Some(Type::String),
-            BuiltInFunction::WriteLine => None,
-        }
-    }
 }
 
 impl Display for BuiltInFunction {

dust-lang/src/dust_error.rs

@@ -1,8 +1,8 @@
 //! Top-level error handling for the Dust language.
-use annotate_snippets::{Level, Renderer, Snippet};
+use annotate_snippets::{Level, Message, Renderer, Snippet};
 use std::fmt::Display;
 
-use crate::{AnalysisError, LexError, ParseError, RuntimeError};
+use crate::{ast::Span, AnalysisError, LexError, ParseError, RuntimeError};
 
 /// An error that occurred during the execution of the Dust language and its
 /// corresponding source code.
@@ -61,12 +61,12 @@ impl<'src> DustError<'src> {
         }
     }
 
-    pub fn position(&self) -> (usize, usize) {
+    pub fn position(&self) -> Option<Span> {
         match self {
             DustError::Runtime { runtime_error, .. } => runtime_error.position(),
-            DustError::Analysis { analysis_error, .. } => analysis_error.position(),
+            DustError::Analysis { analysis_error, .. } => Some(analysis_error.position()),
-            DustError::Parse { parse_error, .. } => parse_error.position(),
+            DustError::Parse { parse_error, .. } => Some(parse_error.position()),
-            DustError::Lex { lex_error, .. } => lex_error.position(),
+            DustError::Lex { lex_error, .. } => Some(lex_error.position()),
         }
     }
 
@@ -83,10 +83,18 @@ impl<'src> DustError<'src> {
         let title = self.title();
         let span = self.position();
         let label = self.to_string();
-        let message = Level::Error.title(title).snippet(
+
+        let message = if let Some(span) = span {
+            Level::Error.title(title).snippet(
                 Snippet::source(self.source())
                     .annotation(Level::Info.span(span.0..span.1).label(&label)),
-        );
+            )
+        } else {
+            Level::Error
+                .title(title)
+                .snippet(Snippet::source(self.source()))
+                .footer(Level::Info.title("No position information available"))
+        };
         let renderer = Renderer::styled();
 
         format!("{}", renderer.render(message))

dust-lang/src/lexer.rs

@@ -437,7 +437,6 @@ impl<'src> Lexer<'src> {
             "mut" => Token::Mut,
             "read_line" => Token::ReadLine,
             "struct" => Token::Struct,
-            "to_string" => Token::ToString,
             "true" => Token::Boolean("true"),
             "while" => Token::While,
             "write_line" => Token::WriteLine,

dust-lang/src/parser.rs

@@ -822,7 +822,7 @@ impl<'src> Parser<'src> {
                     Expression::tuple_access(left, index_node, position)
                 } else {
                     let field = self.parse_identifier()?;
-                    let position = (left.position().0, self.current_position.1);
+                    let position = (left.position().0, field.position.1);
 
                     Expression::field_access(left, field, position)
                 }
@@ -1145,6 +1145,26 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn built_in_function() {
+        let source = "42.to_string()";
+
+        assert_eq!(
+            parse(source),
+            Ok(AbstractSyntaxTree::with_statements([
+                Statement::Expression(Expression::call(
+                    Expression::field_access(
+                        Expression::literal(42, (0, 2)),
+                        Node::new(Identifier::new("to_string"), (3, 12)),
+                        (0, 12)
+                    ),
+                    vec![],
+                    (0, 14)
+                ))
+            ]))
+        );
+    }
+
     #[test]
     fn map_expression() {
         let source = "map { x = '1', y = 2, z = 3.0 }";

dust-lang/src/token.rs

@@ -36,7 +36,6 @@ pub enum Token<'src> {
     ReadLine,
     Str,
     Struct,
-    ToString,
     While,
     WriteLine,
 
@@ -123,7 +122,6 @@ impl<'src> Token<'src> {
             Token::String(text) => TokenOwned::String(text.to_string()),
             Token::Str => TokenOwned::Str,
             Token::Struct => TokenOwned::Struct,
-            Token::ToString => TokenOwned::ToString,
             Token::While => TokenOwned::While,
             Token::WriteLine => TokenOwned::WriteLine,
         }
@@ -181,7 +179,6 @@ impl<'src> Token<'src> {
             Token::Slash => "/",
             Token::Str => "str",
             Token::Struct => "struct",
-            Token::ToString => "to_string",
             Token::While => "while",
             Token::WriteLine => "write_line",
         }
@@ -238,7 +235,6 @@ impl<'src> Token<'src> {
             Token::Str => TokenKind::Str,
             Token::String(_) => TokenKind::String,
             Token::Struct => TokenKind::Struct,
-            Token::ToString => TokenKind::ToString,
             Token::While => TokenKind::While,
             Token::WriteLine => TokenKind::WriteLine,
         }
@@ -332,7 +328,6 @@ pub enum TokenOwned {
     Mut,
     ReadLine,
     Str,
-    ToString,
     While,
     WriteLine,
 
@@ -421,7 +416,6 @@ impl Display for TokenOwned {
             TokenOwned::Str => Token::Str.fmt(f),
             TokenOwned::String(string) => write!(f, "{string}"),
             TokenOwned::Struct => Token::Struct.fmt(f),
-            TokenOwned::ToString => Token::ToString.fmt(f),
             TokenOwned::While => Token::While.fmt(f),
             TokenOwned::WriteLine => Token::WriteLine.fmt(f),
         }
@@ -455,7 +449,6 @@ pub enum TokenKind {
     Map,
     ReadLine,
     Str,
-    ToString,
     While,
     WriteLine,
 
@@ -544,7 +537,6 @@ impl Display for TokenKind {
             TokenKind::Slash => Token::Slash.fmt(f),
             TokenKind::String => write!(f, "string value"),
             TokenKind::Struct => Token::Struct.fmt(f),
-            TokenKind::ToString => Token::ToString.fmt(f),
             TokenKind::While => Token::While.fmt(f),
             TokenKind::WriteLine => Token::WriteLine.fmt(f),
         }
@@ -555,7 +547,7 @@ impl Display for TokenKind {
 pub(crate) mod tests {
     use super::*;
 
-    pub fn all_tokens<'src>() -> [Token<'src>; 52] {
+    pub fn all_tokens<'src>() -> [Token<'src>; 51] {
         [
             Token::Identifier("foobar"),
             Token::Boolean("true"),
@@ -606,7 +598,6 @@ pub(crate) mod tests {
             Token::Star,
             Token::Str,
             Token::Struct,
-            Token::ToString,
             Token::While,
             Token::WriteLine,
         ]

dust-lang/src/type.rs

@@ -371,7 +371,7 @@ impl Ord for Type {
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
 pub struct FunctionType {
     pub name: Identifier,
-    pub type_parameters: Option<Vec<Type>>,
+    pub type_parameters: Option<Vec<Identifier>>,
     pub value_parameters: Option<Vec<(Identifier, Type)>>,
     pub return_type: Option<Box<Type>>,
 }

dust-lang/src/value.rs

@@ -16,8 +16,8 @@ use serde::{
 };
 
 use crate::{
-    AbstractSyntaxTree, Context, EnumType, FunctionType, Identifier, RangeableType, RuntimeError,
+    AbstractSyntaxTree, BuiltInFunction, Context, EnumType, FunctionType, Identifier,
-    StructType, Type, Vm,
+    RangeableType, RuntimeError, StructType, Type, Vm,
 };
 
 /// Dust value representation
@@ -194,7 +194,15 @@ impl Value {
             Value::Character(_) => Type::Character,
             Value::Enum(Enum { r#type, .. }) => Type::Enum(r#type.clone()),
             Value::Float(_) => Type::Float,
-            Value::Function(function) => Type::Function(function.r#type.clone()),
+            Value::Function(Function::BuiltIn(built_in_function)) => Type::Function(FunctionType {
+                name: Identifier::new(built_in_function.name()),
+                type_parameters: built_in_function.type_parameters(),
+                value_parameters: built_in_function.value_parameters(),
+                return_type: built_in_function.return_type().map(Box::new),
+            }),
+            Value::Function(Function::Parsed { name, r#type, body }) => {
+                Type::Function(r#type.clone())
+            }
             Value::Integer(_) => Type::Integer,
             Value::List(values) => {
                 let item_type = values.first().unwrap().r#type();
@@ -255,6 +263,14 @@ impl Value {
     }
 
     pub fn get_field(&self, field: &Identifier) -> Option<Value> {
+        if let "to_string" = field.as_str() {
+            return Some(Value::Function(Function::BuiltIn(
+                BuiltInFunction::ToString {
+                    argument: Box::new(self.clone()),
+                },
+            )));
+        }
+
         match self {
             Value::Mutable(inner) => inner.read().unwrap().get_field(field),
             Value::Struct(Struct::Fields { fields, .. }) => fields.get(field).cloned(),
@@ -1059,41 +1075,54 @@ impl<'de> Deserialize<'de> for Value {
     }
 }
 
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
-pub struct Function {
+pub enum Function {
-    pub name: Identifier,
+    BuiltIn(BuiltInFunction),
-    pub r#type: FunctionType,
+    Parsed {
-    pub body: Arc<AbstractSyntaxTree>,
+        name: Identifier,
+        r#type: FunctionType,
+        body: AbstractSyntaxTree,
+    },
 }
 
 impl Function {
     pub fn call(
-        &self,
+        self,
         _type_arguments: Option<Vec<Type>>,
         value_arguments: Option<Vec<Value>>,
         context: &Context,
     ) -> Result<Option<Value>, RuntimeError> {
+        match self {
+            Function::BuiltIn(built_in_function) => built_in_function
+                .call(_type_arguments, value_arguments)
+                .map_err(|error| RuntimeError::BuiltInFunctionError { error }),
+            Function::Parsed { r#type, body, .. } => {
                 let new_context = Context::with_data_from(context);
 
                 if let (Some(value_parameters), Some(value_arguments)) =
-            (&self.r#type.value_parameters, value_arguments)
+                    (&r#type.value_parameters, value_arguments)
                 {
                     for ((identifier, _), value) in value_parameters.iter().zip(value_arguments) {
                         new_context.set_variable_value(identifier.clone(), value);
                     }
                 }
 
-        let mut vm = Vm::new(self.body.as_ref().clone(), new_context);
+                let mut vm = Vm::new(body, new_context);
 
                 vm.run()
             }
+        }
+    }
 }
 
 impl Display for Function {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "fn {}", self.name)?;
+        match self {
+            Function::BuiltIn(built_in_function) => write!(f, "{}", built_in_function),
+            Function::Parsed { name, r#type, body } => {
+                write!(f, "fn {}", name)?;
 
-        if let Some(type_parameters) = &self.r#type.type_parameters {
+                if let Some(type_parameters) = &r#type.type_parameters {
                     write!(f, "<")?;
 
                     for (index, type_parameter) in type_parameters.iter().enumerate() {
@@ -1109,7 +1138,7 @@ impl Display for Function {
 
                 write!(f, "(")?;
 
-        if let Some(value_paramers) = &self.r#type.value_parameters {
+                if let Some(value_paramers) = &r#type.value_parameters {
                     for (index, (identifier, r#type)) in value_paramers.iter().enumerate() {
                         if index > 0 {
                             write!(f, ", ")?;
@@ -1121,89 +1150,13 @@ impl Display for Function {
 
                 write!(f, ") {{")?;
 
-        for statement in &self.body.statements {
+                for statement in &body.statements {
                     write!(f, "{}", statement)?;
                 }
 
                 write!(f, "}}")
             }
-}
-
-impl Serialize for Function {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        let mut ser = serializer.serialize_struct("Function", 3)?;
-
-        ser.serialize_field("name", &self.name)?;
-        ser.serialize_field("type", &self.r#type)?;
-        ser.serialize_field("body", self.body.as_ref())?;
-
-        ser.end()
         }
-}
-
-impl<'de> Deserialize<'de> for Function {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: Deserializer<'de>,
-    {
-        struct FunctionVisitor;
-
-        impl<'de> Visitor<'de> for FunctionVisitor {
-            type Value = Function;
-
-            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-                formatter.write_str("a function")
-            }
-
-            fn visit_map<A>(self, mut map: A) -> Result<Function, A::Error>
-            where
-                A: MapAccess<'de>,
-            {
-                let mut name = None;
-                let mut r#type = None;
-                let mut body = None;
-
-                while let Some(key) = map.next_key()? {
-                    match key {
-                        "name" => {
-                            if name.is_some() {
-                                return Err(de::Error::duplicate_field("name"));
-                            }
-
-                            name = Some(map.next_value()?);
-                        }
-                        "type" => {
-                            if r#type.is_some() {
-                                return Err(de::Error::duplicate_field("type"));
-                            }
-
-                            r#type = Some(map.next_value()?);
-                        }
-                        "body" => {
-                            if body.is_some() {
-                                return Err(de::Error::duplicate_field("body"));
-                            }
-
-                            body = Some(map.next_value().map(Arc::new)?);
-                        }
-                        _ => {
-                            return Err(de::Error::unknown_field(key, &["name", "type", "body"]));
-                        }
-                    }
-                }
-
-                let name = name.ok_or_else(|| de::Error::missing_field("name"))?;
-                let r#type = r#type.ok_or_else(|| de::Error::missing_field("type"))?;
-                let body = body.ok_or_else(|| de::Error::missing_field("body"))?;
-
-                Ok(Function { name, r#type, body })
-            }
-        }
-
-        deserializer.deserialize_struct("Function", &["name", "type", "body"], FunctionVisitor)
     }
 }
 

dust-lang/src/vm.rs

@@ -20,9 +20,8 @@ use crate::{
         OperatorExpression, PrimitiveValueExpression, RangeExpression, Span, Statement,
         StructDefinition, StructExpression,
     },
-    constructor::FieldsConstructor,
     parse, Analyzer, BuiltInFunctionError, Constructor, Context, ContextData, DustError,
-    Expression, Identifier, ParseError, Struct, StructType, Type, Value, ValueError,
+    Expression, Function, Identifier, ParseError, StructType, Type, Value, ValueError,
 };
 
 /// Run the source code and return the result.
@@ -609,6 +608,9 @@ impl Vm {
 
     fn run_literal(&self, literal: LiteralExpression) -> Result<Evaluation, RuntimeError> {
         let value = match literal {
+            LiteralExpression::BuiltInFunction(built_in_function) => {
+                Value::Function(Function::BuiltIn(built_in_function))
+            }
             LiteralExpression::String(string) => Value::String(string),
             LiteralExpression::Primitive(primitive_expression) => match primitive_expression {
                 PrimitiveValueExpression::Boolean(boolean) => Value::Boolean(boolean),
@@ -934,7 +936,6 @@ pub enum RuntimeError {
     // These should be prevented by running the analyzer before the VM
     BuiltInFunctionError {
         error: BuiltInFunctionError,
-        position: Span,
     },
     EnumVariantNotFound {
         identifier: Identifier,
@@ -1006,8 +1007,9 @@ pub enum RuntimeError {
 }
 
 impl RuntimeError {
-    pub fn position(&self) -> Span {
+    pub fn position(&self) -> Option<Span> {
-        match self {
+        let position = match self {
+            Self::BuiltInFunctionError { .. } => return None,
             Self::ParseError(parse_error) => parse_error.position(),
             Self::Expression { position, .. } => *position,
             Self::Statement { position, .. } => *position,
@@ -1016,7 +1018,6 @@ impl RuntimeError {
                 right_position,
                 ..
             } => (left_position.0, right_position.1),
-            Self::BuiltInFunctionError { position, .. } => *position,
             Self::EnumVariantNotFound { position, .. } => *position,
             Self::ExpectedBoolean { position } => *position,
             Self::ExpectedConstructor { position, .. } => *position,
@@ -1042,7 +1043,9 @@ impl RuntimeError {
             Self::UndefinedProperty {
                 property_position, ..
             } => *property_position,
-        }
+        };
+
+        Some(position)
     }
 }