Fix function validation and parsing

src/abstract_tree/assignment.rs

@@ -42,6 +42,8 @@ impl AbstractTree for Assignment {
     }
 
     fn validate(&self, context: &Context) -> Result<(), ValidationError> {
+        self.statement.validate(context)?;
+
         let statement_type = self.statement.expected_type(context)?;
 
         if let Some(expected) = &self.r#type {

src/abstract_tree/block.rs

@@ -1,7 +1,6 @@
 use crate::{
     context::Context,
     error::{RuntimeError, ValidationError},
-    Value,
 };
 
 use super::{AbstractTree, Action, Statement, Type};
@@ -19,9 +18,11 @@ impl Block {
 
 impl AbstractTree for Block {
     fn expected_type(&self, _context: &Context) -> Result<Type, ValidationError> {
-        let final_statement = self.statements.last().unwrap();
+        if let Some(statement) = self.statements.last() {
-
+            statement.expected_type(_context)
-        final_statement.expected_type(_context)
+        } else {
+            Ok(Type::None)
+        }
     }
 
     fn validate(&self, _context: &Context) -> Result<(), ValidationError> {
@@ -33,23 +34,26 @@ impl AbstractTree for Block {
     }
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
-        let mut previous = Value::none();
+        let mut previous = Action::None;
 
         for statement in self.statements {
             let action = statement.run(_context)?;
             previous = match action {
-                Action::Return(value) => value,
+                Action::Return(value) => Action::Return(value),
                 r#break => return Ok(r#break),
             };
         }
 
-        Ok(Action::Return(previous))
+        Ok(previous)
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use crate::abstract_tree::{Expression, ValueNode};
+    use crate::{
+        abstract_tree::{Expression, ValueNode},
+        Value,
+    };
 
     use super::*;
 

src/abstract_tree/value_node.rs

@@ -6,7 +6,7 @@ use crate::{
     Value,
 };
 
-use super::{AbstractTree, Action, Expression, Identifier, Statement, Type};
+use super::{AbstractTree, Action, Block, Expression, Identifier, Type};
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum ValueNode {
@@ -21,7 +21,7 @@ pub enum ValueNode {
     Function {
         parameters: Vec<(Identifier, Type)>,
         return_type: Type,
-        body: Box<Statement>,
+        body: Block,
     },
 }
 
@@ -72,6 +72,23 @@ impl AbstractTree for ValueNode {
             }
         }
 
+        if let ValueNode::Function {
+            parameters,
+            return_type,
+            body,
+        } = self
+        {
+            let function_context = Context::new();
+
+            for (identifier, r#type) in parameters {
+                function_context.set_type(identifier.clone(), r#type.clone())?;
+            }
+
+            let actual_return_type = body.expected_type(&function_context)?;
+
+            return_type.check(&actual_return_type)?;
+        }
+
         Ok(())
     }
 
@@ -115,7 +132,7 @@ impl AbstractTree for ValueNode {
                 parameters,
                 return_type,
                 body,
-            } => Value::function(parameters, return_type, *body),
+            } => Value::function(parameters, return_type, body),
         };
 
         Ok(Action::Return(value))

src/lexer.rs

@@ -210,6 +210,7 @@ pub fn lexer<'src>() -> impl Parser<
     .map(Token::Control);
 
     let keyword = choice((
+        just("any").padded(),
         just("bool").padded(),
         just("break").padded(),
         just("else").padded(),
@@ -218,6 +219,7 @@ pub fn lexer<'src>() -> impl Parser<
         just("if").padded(),
         just("list").padded(),
         just("map").padded(),
+        just("none").padded(),
         just("range").padded(),
         just("str").padded(),
         just("loop").padded(),

src/parser.rs

@@ -47,10 +47,21 @@ pub fn parser<'src>() -> DustParser<'src> {
         }
     };
 
+    let basic_value = select! {
+        Token::Boolean(boolean) => ValueNode::Boolean(boolean),
+        Token::Integer(integer) => ValueNode::Integer(integer),
+        Token::Float(float) => ValueNode::Float(float),
+        Token::String(string) => ValueNode::String(string.to_string()),
+    }
+    .map(|value| Expression::Value(value))
+    .boxed();
+
     let basic_type = choice((
+        just(Token::Keyword("any")).to(Type::Any),
         just(Token::Keyword("bool")).to(Type::Boolean),
         just(Token::Keyword("float")).to(Type::Float),
         just(Token::Keyword("int")).to(Type::Integer),
+        just(Token::Keyword("none")).to(Type::None),
         just(Token::Keyword("range")).to(Type::Range),
         just(Token::Keyword("str")).to(Type::String),
         just(Token::Keyword("list")).to(Type::List),
@@ -80,16 +91,18 @@ pub fn parser<'src>() -> DustParser<'src> {
             .map(|identifier| Type::Custom(identifier)),
     )));
 
-    let expression = recursive(|expression| {
+    let statement = recursive(|statement| {
-        let basic_value = select! {
+        let block = statement
-            Token::Boolean(boolean) => ValueNode::Boolean(boolean),
+            .clone()
-            Token::Integer(integer) => ValueNode::Integer(integer),
+            .repeated()
-            Token::Float(float) => ValueNode::Float(float),
+            .collect()
-            Token::String(string) => ValueNode::String(string.to_string()),
+            .delimited_by(
-        }
+                just(Token::Control(Control::CurlyOpen)),
-        .map(|value| Expression::Value(value))
+                just(Token::Control(Control::CurlyClose)),
-        .boxed();
+            )
+            .map(|statements| Block::new(statements));
 
+        let expression = recursive(|expression| {
             let identifier_expression = identifier
                 .clone()
                 .map(|identifier| Expression::Identifier(identifier))
@@ -143,7 +156,46 @@ pub fn parser<'src>() -> DustParser<'src> {
                 .map(|(name, variant)| Expression::Value(ValueNode::Enum(name, variant)))
                 .boxed();
 
+            let function = identifier
+                .clone()
+                .then(type_specification.clone())
+                .separated_by(just(Token::Control(Control::Comma)))
+                .collect::<Vec<(Identifier, Type)>>()
+                .delimited_by(
+                    just(Token::Control(Control::ParenOpen)),
+                    just(Token::Control(Control::ParenClose)),
+                )
+                .then(type_specification.clone())
+                .then(block.clone())
+                .map(|((parameters, return_type), body)| {
+                    Expression::Value(ValueNode::Function {
+                        parameters,
+                        return_type,
+                        body,
+                    })
+                })
+                .boxed();
+
+            let function_expression = choice((identifier_expression.clone(), function.clone()));
+
+            let function_call = function_expression
+                .then(
+                    expression
+                        .clone()
+                        .separated_by(just(Token::Control(Control::Comma)))
+                        .collect()
+                        .delimited_by(
+                            just(Token::Control(Control::ParenOpen)),
+                            just(Token::Control(Control::ParenClose)),
+                        ),
+                )
+                .map(|(function, arguments)| {
+                    Expression::FunctionCall(FunctionCall::new(function, arguments))
+                })
+                .boxed();
+
             let atom = choice((
+                function_call,
                 identifier_expression.clone(),
                 basic_value.clone(),
                 list.clone(),
@@ -176,7 +228,9 @@ pub fn parser<'src>() -> DustParser<'src> {
                     infix(
                         left(1),
                         just(Token::Operator(GreaterOrEqual)),
-                    |left, right| Expression::Logic(Box::new(Logic::GreaterOrEqual(left, right))),
+                        |left, right| {
+                            Expression::Logic(Box::new(Logic::GreaterOrEqual(left, right)))
+                        },
                     ),
                     infix(
                         left(1),
@@ -213,6 +267,7 @@ pub fn parser<'src>() -> DustParser<'src> {
                 .boxed();
 
             choice((
+                function,
                 range,
                 r#enum,
                 logic_math_and_index,
@@ -221,9 +276,9 @@ pub fn parser<'src>() -> DustParser<'src> {
                 map,
                 basic_value,
             ))
+            .boxed()
         });
 
-    let statement = recursive(|statement| {
         let expression_statement = expression
             .clone()
             .map(|expression| Statement::Expression(expression))
@@ -247,16 +302,7 @@ pub fn parser<'src>() -> DustParser<'src> {
             })
             .boxed();
 
-        let block = statement
+        let block_statement = block.clone().map(|block| Statement::Block(block));
-            .clone()
-            .repeated()
-            .collect()
-            .delimited_by(
-                just(Token::Control(Control::CurlyOpen)),
-                just(Token::Control(Control::CurlyClose)),
-            )
-            .map(|statements| Statement::Block(Block::new(statements)))
-            .boxed();
 
         let r#loop = statement
             .clone()
@@ -283,54 +329,16 @@ pub fn parser<'src>() -> DustParser<'src> {
             })
             .boxed();
 
-        let function = identifier
-            .clone()
-            .then(type_specification.clone())
-            .separated_by(just(Token::Control(Control::Comma)))
-            .collect::<Vec<(Identifier, Type)>>()
-            .delimited_by(
-                just(Token::Control(Control::ParenOpen)),
-                just(Token::Control(Control::ParenClose)),
-            )
-            .then(type_specification)
-            .then(statement.clone())
-            .map(|((parameters, return_type), body)| {
-                Statement::Expression(Expression::Value(ValueNode::Function {
-                    parameters,
-                    return_type,
-                    body: Box::new(body),
-                }))
-            });
-
-        let function_call = expression
-            .clone()
-            .then(
-                expression
-                    .clone()
-                    .separated_by(just(Token::Control(Control::Comma)))
-                    .collect()
-                    .delimited_by(
-                        just(Token::Control(Control::ParenOpen)),
-                        just(Token::Control(Control::ParenClose)),
-                    ),
-            )
-            .map(|(function, arguments)| {
-                Statement::Expression(Expression::FunctionCall(FunctionCall::new(
-                    function, arguments,
-                )))
-            });
-
         choice((
-            function_call,
             assignment,
             expression_statement,
             r#break,
-            block,
+            block_statement,
             r#loop,
             if_else,
-            function,
         ))
         .then_ignore(just(Token::Control(Control::Semicolon)).or_not())
+        .boxed()
     });
 
     statement
@@ -368,13 +376,13 @@ mod tests {
     #[test]
     fn function() {
         assert_eq!(
-            parse(&lex("(x: int): int x ").unwrap()).unwrap()[0].0,
+            parse(&lex("(x: int): int { x }").unwrap()).unwrap()[0].0,
             Statement::Expression(Expression::Value(ValueNode::Function {
                 parameters: vec![(Identifier::new("x"), Type::Integer)],
                 return_type: Type::Integer,
-                body: Box::new(Statement::Expression(Expression::Identifier(
+                body: Block::new(vec![Statement::Expression(Expression::Identifier(
                     Identifier::new("x")
-                )))
+                ))])
             }))
         )
     }

src/value.rs

@@ -13,7 +13,7 @@ use stanza::{
 };
 
 use crate::{
-    abstract_tree::{AbstractTree, Action, Identifier, Statement, Type},
+    abstract_tree::{AbstractTree, Action, Block, Identifier, Type},
     context::Context,
     error::{RuntimeError, ValidationError},
 };
@@ -73,11 +73,7 @@ impl Value {
         Value(Arc::new(ValueInner::Enum(name, variant)))
     }
 
-    pub fn function(
+    pub fn function(parameters: Vec<(Identifier, Type)>, return_type: Type, body: Block) -> Self {
-        parameters: Vec<(Identifier, Type)>,
-        return_type: Type,
-        body: Statement,
-    ) -> Self {
         Value(Arc::new(ValueInner::Function(Function::Parsed(
             ParsedFunction {
                 parameters,
@@ -369,7 +365,7 @@ impl Function {
 pub struct ParsedFunction {
     parameters: Vec<(Identifier, Type)>,
     return_type: Type,
-    body: Statement,
+    body: Block,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]

tests/functions.rs

@@ -38,7 +38,7 @@ fn callback() {
             foobar = (cb : () -> str) : str {
                 cb()
             }
-            foobar(() : str { 'Hiya' })
+            foobar(() : str 'Hiya')
             ",
         ),
         Ok(Some(Value::string("Hiya".to_string())))
@@ -62,7 +62,7 @@ fn function_context_does_not_capture_values() {
         ),
         Err(vec![Error::Validation {
             error: ValidationError::VariableNotFound(Identifier::new("x")),
-            span: (0..0).into()
+            span: (32..66).into()
         }])
     );
 

tests/variables.rs

@@ -1,5 +1,5 @@
 use dust_lang::{
-    abstract_tree::{Expression, Identifier, Statement, Type},
+    abstract_tree::{Block, Expression, Identifier, Statement, Type},
     error::{Error, TypeCheckError, ValidationError},
     *,
 };
@@ -41,7 +41,9 @@ fn function_variable() {
         Ok(Some(Value::function(
             vec![(Identifier::new("x"), Type::Integer)],
             Type::Integer,
-            Statement::Expression(Expression::Identifier(Identifier::new("x")))
+            Block::new(vec![Statement::Expression(Expression::Identifier(
+                Identifier::new("x")
+            ))])
         )))
     );
 }