Finish function syntax

examples/fibonacci.ds

@@ -1,4 +1,4 @@
-fib <(int) -> int> = fn |i| {
+fib = (fn i <int>) <int> {
 	if i <= 1 {
 		1
 	} else {

src/abstract_tree/function_call.rs

@@ -51,20 +51,14 @@ impl AbstractTree for FunctionCall {
             for (argument, r#type) in argument_type_pairs {
                 let argument_type = argument.expected_type(context)?;
 
-                if let Type::Function { return_type, .. } = argument_type {
-                    r#type.check(&return_type)?;
-                } else {
-                    r#type.check(&argument_type)?;
-                }
+                r#type.check(&argument_type)?;
             }
         }
 
-        let function_call = FunctionCall {
+        Ok(FunctionCall {
             function_expression,
             arguments,
-        };
-
-        Ok(function_call)
+        })
     }
 
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
@@ -137,7 +131,7 @@ mod tests {
         assert_eq!(
             evaluate(
                 "
-                foobar <(str) -> str> = fn |message| { message }
+                foobar = (fn message <str>) <str> { message }
                 (foobar 'Hiya')
                 ",
             ),
@@ -150,11 +144,11 @@ mod tests {
         assert_eq!(
             evaluate(
                 "
-                foobar <(() -> str) -> str> = fn |cb| {
+                foobar = (fn cb <() -> str>) <str> {
                     (cb)
                 }
 
-                (foobar fn || { 'Hiya' })
+                (foobar (fn) <str> { 'Hiya' })
                 ",
             ),
             Ok(Value::String("Hiya".to_string()))

src/abstract_tree/function_declaration.rs

@@ -0,0 +1,83 @@
+use serde::{Deserialize, Serialize};
+use tree_sitter::Node;
+
+use crate::{AbstractTree, Block, Function, Identifier, Map, Result, Type, TypeDefinition, Value};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct FunctionDeclaration {
+    name: Option<Identifier>,
+    r#type: Option<Type>,
+    parameters: Vec<Identifier>,
+    body: Block,
+}
+
+impl AbstractTree for FunctionDeclaration {
+    fn from_syntax_node(source: &str, node: Node, context: &Map) -> Result<Self> {
+        let name_node = node.child_by_field_name("name");
+        let name = if let Some(child) = name_node {
+            Some(Identifier::from_syntax_node(source, child, context)?)
+        } else {
+            None
+        };
+
+        let type_definition_node = node.child_by_field_name("type");
+        let type_definition = if let Some(child) = type_definition_node {
+            Some(TypeDefinition::from_syntax_node(source, child, context)?)
+        } else {
+            None
+        };
+
+        let mut parameters = Vec::new();
+
+        if node.child_by_field_name("parameters").is_some() {
+            for index in 3..node.child_count() - 2 {
+                let child = node.child(index).unwrap();
+
+                if child.is_named() {
+                    let parameter = Identifier::from_syntax_node(source, child, context)?;
+
+                    parameters.push(parameter);
+                }
+            }
+        }
+
+        let body_node = node.child_by_field_name("body").unwrap();
+        let body = Block::from_syntax_node(source, body_node, context)?;
+
+        Ok(FunctionDeclaration {
+            name,
+            r#type: type_definition.map(|defintion| defintion.take_inner()),
+            parameters,
+            body,
+        })
+    }
+
+    fn run(&self, _source: &str, context: &Map) -> Result<Value> {
+        let value = Value::Function(Function::new(
+            self.parameters.clone(),
+            self.body.clone(),
+            self.r#type.clone(),
+        ));
+
+        if let Some(name) = &self.name {
+            let key = name.inner().clone();
+
+            context.set(key, value, self.r#type.clone())?;
+
+            Ok(Value::Empty)
+        } else {
+            Ok(value)
+        }
+    }
+
+    fn expected_type(&self, _context: &Map) -> Result<Type> {
+        if self.name.is_some() {
+            Ok(Type::Empty)
+        } else {
+            Ok(self.r#type.clone().unwrap_or(Type::Function {
+                parameter_types: vec![Type::Any; self.parameters.len()],
+                return_type: Box::new(Type::Any),
+            }))
+        }
+    }
+}

src/abstract_tree/identifier.rs

@@ -42,8 +42,8 @@ impl AbstractTree for Identifier {
     }
 
     fn expected_type(&self, context: &Map) -> Result<Type> {
-        if let Some((value, _)) = context.variables()?.get(&self.0) {
-            Ok(value.r#type())
+        if let Some((_value, r#type)) = context.variables()?.get(&self.0) {
+            Ok(r#type.clone())
         } else {
             for built_in_function in BUILT_IN_FUNCTIONS {
                 if self.0 == built_in_function.name() {
@@ -51,7 +51,7 @@ impl AbstractTree for Identifier {
                 }
             }
 
-            Ok(Type::Any)
+            Ok(Type::Empty)
         }
     }
 }

src/abstract_tree/index.rs

@@ -116,7 +116,7 @@ mod tests {
         let test = evaluate(
             "
             x = [1 2 3]
-            y <() -> int> = fn || { 0 }
+            y = (fn) <int> { 0 }
             x:(y)
             ",
         )

src/abstract_tree/type_definition.rs

@@ -0,0 +1,217 @@
+use std::fmt::{self, Display, Formatter};
+
+use serde::{Deserialize, Serialize};
+use tree_sitter::Node;
+
+use crate::{AbstractTree, Error, Map, Result, Value};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct TypeDefinition {
+    r#type: Type,
+}
+
+impl TypeDefinition {
+    pub fn new(r#type: Type) -> Self {
+        Self { r#type }
+    }
+
+    pub fn inner(&self) -> &Type {
+        &self.r#type
+    }
+
+    pub fn take_inner(self) -> Type {
+        self.r#type
+    }
+}
+
+impl AbstractTree for TypeDefinition {
+    fn from_syntax_node(source: &str, node: Node, context: &Map) -> Result<Self> {
+        Error::expect_syntax_node(source, "type_definition", node)?;
+
+        let type_node = node.child(1).unwrap();
+        let r#type = Type::from_syntax_node(source, type_node, context)?;
+
+        Ok(TypeDefinition { r#type })
+    }
+
+    fn run(&self, source: &str, context: &Map) -> Result<Value> {
+        self.r#type.run(source, context)
+    }
+
+    fn expected_type(&self, context: &Map) -> Result<Type> {
+        self.r#type.expected_type(context)
+    }
+}
+
+impl Display for TypeDefinition {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        write!(f, "<{}>", self.r#type)
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub enum Type {
+    Any,
+    Boolean,
+    Empty,
+    Float,
+    Function {
+        parameter_types: Vec<Type>,
+        return_type: Box<Type>,
+    },
+    Integer,
+    List(Box<Type>),
+    Map,
+    Number,
+    String,
+}
+
+impl Type {
+    pub fn check(&self, other: &Type) -> Result<()> {
+        match (self, other) {
+            (Type::Any, _)
+            | (_, Type::Any)
+            | (Type::Boolean, Type::Boolean)
+            | (Type::Empty, Type::Empty)
+            | (Type::Float, Type::Float)
+            | (Type::Integer, Type::Integer)
+            | (Type::Map, Type::Map)
+            | (Type::Number, Type::Number)
+            | (Type::Number, Type::Integer)
+            | (Type::Number, Type::Float)
+            | (Type::Integer, Type::Number)
+            | (Type::Float, Type::Number)
+            | (Type::String, Type::String) => Ok(()),
+            (Type::List(self_item_type), Type::List(other_item_type)) => {
+                self_item_type.check(&other_item_type)
+            }
+            (
+                Type::Function {
+                    parameter_types: self_parameter_types,
+                    return_type: self_return_type,
+                },
+                Type::Function {
+                    parameter_types: other_parameter_types,
+                    return_type: other_return_type,
+                },
+            ) => {
+                let parameter_type_pairs = self_parameter_types
+                    .iter()
+                    .zip(other_parameter_types.iter());
+
+                for (self_parameter_type, other_parameter_type) in parameter_type_pairs {
+                    self_parameter_type.check(&other_parameter_type)?;
+                }
+
+                self_return_type.check(other_return_type)?;
+
+                Ok(())
+            }
+            _ => Err(Error::TypeCheck {
+                expected: self.clone(),
+                actual: other.clone(),
+            }),
+        }
+    }
+}
+
+impl AbstractTree for Type {
+    fn from_syntax_node(source: &str, node: Node, context: &Map) -> Result<Self> {
+        Error::expect_syntax_node(source, "type", node)?;
+
+        let type_node = node.child(0).unwrap();
+
+        let r#type = match type_node.kind() {
+            "[" => {
+                let item_type_node = node.child(1).unwrap();
+                let item_type = Type::from_syntax_node(source, item_type_node, context)?;
+
+                Type::List(Box::new(item_type))
+            }
+            "any" => Type::Any,
+            "bool" => Type::Boolean,
+            "float" => Type::Float,
+            "(" => {
+                let child_count = node.child_count();
+                let mut parameter_types = Vec::new();
+
+                for index in 1..child_count - 2 {
+                    let child = node.child(index).unwrap();
+
+                    if child.is_named() {
+                        let parameter_type = Type::from_syntax_node(source, child, context)?;
+
+                        parameter_types.push(parameter_type);
+                    }
+                }
+
+                let final_node = node.child(child_count - 1).unwrap();
+                let return_type = if final_node.is_named() {
+                    Type::from_syntax_node(source, final_node, context)?
+                } else {
+                    Type::Empty
+                };
+
+                Type::Function {
+                    parameter_types,
+                    return_type: Box::new(return_type),
+                }
+            }
+            "int" => Type::Integer,
+            "map" => Type::Map,
+            "num" => Type::Number,
+            "str" => Type::String,
+            _ => {
+                return Err(Error::UnexpectedSyntaxNode {
+                    expected: "any, bool, float, fn, int, list, map, num or str",
+                    actual: type_node.kind(),
+                    location: type_node.start_position(),
+                    relevant_source: source[type_node.byte_range()].to_string(),
+                })
+            }
+        };
+
+        Ok(r#type)
+    }
+
+    fn run(&self, _source: &str, _context: &Map) -> Result<Value> {
+        Ok(Value::Empty)
+    }
+
+    fn expected_type(&self, _context: &Map) -> Result<Type> {
+        Ok(Type::Empty)
+    }
+}
+
+impl Display for Type {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        match self {
+            Type::Any => write!(f, "any"),
+            Type::Boolean => write!(f, "bool"),
+            Type::Empty => write!(f, "empty"),
+            Type::Float => write!(f, "float"),
+            Type::Function {
+                parameter_types,
+                return_type,
+            } => {
+                write!(f, "(")?;
+
+                for parameter_type in parameter_types {
+                    write!(f, "{parameter_type}")?;
+
+                    if parameter_type != parameter_types.last().unwrap() {
+                        write!(f, " ")?;
+                    }
+                }
+
+                write!(f, ")")?;
+                write!(f, " -> {return_type}")
+            }
+            Type::Integer => write!(f, "int"),
+            Type::List(item_type) => write!(f, "[{item_type}]"),
+            Type::Map => write!(f, "map"),
+            Type::Number => write!(f, "num"),
+            Type::String => write!(f, "str"),
+        }
+    }
+}

src/abstract_tree/value_node.rs

@@ -5,7 +5,7 @@ use tree_sitter::Node;
 
 use crate::{
     AbstractTree, Block, Error, Expression, Function, Identifier, List, Map, Result, Statement,
-    Type, Value,
+    Type, TypeDefinition, Value,
 };
 
 #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
@@ -31,21 +31,38 @@ impl AbstractTree for ValueNode {
             "function" => {
                 let child_count = child.child_count();
                 let mut parameters = Vec::new();
+                let mut parameter_types = Vec::new();
 
                 for index in 2..child_count - 1 {
                     let child = child.child(index).unwrap();
 
-                    if child.is_named() {
+                    if child.kind() == "identifier" {
                         let identifier = Identifier::from_syntax_node(source, child, context)?;
 
                         parameters.push(identifier);
                     }
+
+                    if child.kind() == "type_definition" {
+                        let type_definition =
+                            TypeDefinition::from_syntax_node(source, child, context)?;
+
+                        parameter_types.push(type_definition.take_inner());
+                    }
                 }
 
+                let return_type_node = child.child(child_count - 2).unwrap();
+                let return_type =
+                    TypeDefinition::from_syntax_node(source, return_type_node, context)?;
+
                 let body_node = child.child(child_count - 1).unwrap();
                 let body = Block::from_syntax_node(source, body_node, context)?;
 
-                ValueNode::Function(Function::new(parameters, body, None))
+                let r#type = Type::Function {
+                    parameter_types,
+                    return_type: Box::new(return_type.take_inner()),
+                };
+
+                ValueNode::Function(Function::new(parameters, body, Some(r#type)))
             }
             "integer" => ValueNode::Integer(source[child.byte_range()].to_string()),
             "string" => {

src/value/function.rs

@@ -78,36 +78,7 @@ impl Function {
             let value = expression.run(source, context)?;
             let value_type = value.r#type();
 
-            match argument_type {
-                Type::Any => {}
-                Type::Boolean => {
-                    value.as_boolean()?;
-                }
-                Type::Empty => {
-                    value.as_empty()?;
-                }
-                Type::Float => {
-                    value.as_float()?;
-                }
-                Type::Function { .. } => {
-                    value.as_function()?;
-                }
-                Type::Integer => {
-                    value.as_integer()?;
-                }
-                Type::List(_) => {
-                    value.as_list()?;
-                }
-                Type::Map => {
-                    value.as_map()?;
-                }
-                Type::Number => {
-                    value.as_number()?;
-                }
-                Type::String => {
-                    value.as_string()?;
-                }
-            };
+            argument_type.check(&value_type)?;
 
             let key = identifier.inner().clone();
 
@@ -118,36 +89,7 @@ impl Function {
 
         let return_value = self.body.run(source, &function_context)?;
 
-        match return_type.as_ref() {
-            Type::Any => {}
-            Type::Boolean => {
-                return_value.as_boolean()?;
-            }
-            Type::Empty => {
-                return_value.as_empty()?;
-            }
-            Type::Float => {
-                return_value.as_float()?;
-            }
-            Type::Function { .. } => {
-                return_value.as_function()?;
-            }
-            Type::Integer => {
-                return_value.as_integer()?;
-            }
-            Type::List(_) => {
-                return_value.as_list()?;
-            }
-            Type::Map => {
-                return_value.as_map()?;
-            }
-            Type::Number => {
-                return_value.as_number()?;
-            }
-            Type::String => {
-                return_value.as_string()?;
-            }
-        };
+        return_type.check(&return_value.r#type())?;
 
         Ok(return_value)
     }

std/list.ds

@@ -0,0 +1,29 @@
+contains <([any], any) -> bool> = fn |list, target| {
+	for item in list {
+		if item == target {
+			return true;
+		}
+	}
+
+	false
+}
+
+find <([any], any) -> bool> = fn |list, target| {
+	for item in list {
+		if item == target {
+			return item;
+		}
+	}
+}
+
+reverse <([any]) -> [any]> = fn |list| {
+	new_list = []
+	index = (length list) - 1;
+	
+	while index >= 0 {
+		new_list += list:index
+		index -= 1
+	}
+
+	new_list
+}

tree-sitter-dust/corpus/functions.txt

@@ -1,8 +1,8 @@
 ================================================================================
-Simple Function
+Anonymous Function
 ================================================================================
 
-fn || { "Hiya" }
+(fn) <str> { "Hiya" }
 
 --------------------------------------------------------------------------------
 
@@ -11,6 +11,8 @@ fn || { "Hiya" }
     (expression
       (value
         (function
+          (type_definition
+            (type))
           (block
             (statement
               (expression
@@ -18,10 +20,12 @@ fn || { "Hiya" }
                   (string))))))))))
 
 ================================================================================
-Function Assignment
+Function Declaration
 ================================================================================
 
-foobar <(str) -> str> = fn |text| { text }
+foobar = (fn x <int>, y <int>) <int> {
+  x + y
+}
 
 --------------------------------------------------------------------------------
 
@@ -29,20 +33,28 @@ foobar <(str) -> str> = fn |text| { text }
   (statement
     (assignment
       (identifier)
-      (type_definition
-        (type
-          (type)
-          (type)))
       (assignment_operator)
       (statement
         (expression
           (value
             (function
               (identifier)
+              (type_definition
+                (type))
+              (identifier)
+              (type_definition
+                (type))
+              (type_definition
+                (type))
               (block
                 (statement
                   (expression
-                    (identifier)))))))))))
+                    (math
+                      (expression
+                        (identifier))
+                      (math_operator)
+                      (expression
+                        (identifier)))))))))))))
 
 ================================================================================
 Function Call
@@ -62,42 +74,6 @@ Function Call
           (value
             (string)))))))
 
-================================================================================
-Complex Function
-================================================================================
-
-fn |message number| {
-  (output message)
-  (output number)
-}
-
---------------------------------------------------------------------------------
-
-(root
-  (statement
-    (expression
-      (value
-        (function
-          (identifier)
-          (identifier)
-          (block
-            (statement
-              (expression
-                (function_call
-                  (expression
-                    (identifier
-                      (built_in_function)))
-                  (expression
-                    (identifier)))))
-            (statement
-              (expression
-                (function_call
-                  (expression
-                    (identifier
-                      (built_in_function)))
-                  (expression
-                    (identifier)))))))))))
-
 ================================================================================
 Complex Function Call
 ================================================================================
@@ -138,50 +114,3 @@ Complex Function Call
                 (expression
                   (value
                     (integer)))))))))))
-
-================================================================================
-Callback Function
-================================================================================
-
-foobar <(() -> str) -> str> = fn |cb| {
-    (cb)
-}
-
-(foobar fn || { 'Hiya' })
-
---------------------------------------------------------------------------------
-
-(root
-  (statement
-    (assignment
-      (identifier)
-      (type_definition
-        (type
-          (type
-            (type))
-          (type)))
-      (assignment_operator)
-      (statement
-        (expression
-          (value
-            (function
-              (identifier)
-              (block
-                (statement
-                  (expression
-                    (function_call
-                      (expression
-                        (identifier))))))))))))
-  (statement
-    (expression
-      (function_call
-        (expression
-          (identifier))
-        (expression
-          (value
-            (function
-              (block
-                (statement
-                  (expression
-                    (value
-                      (string))))))))))))

tree-sitter-dust/grammar.js

@@ -69,9 +69,9 @@ module.exports = grammar({
 
     value: $ =>
       choice(
+        $.function,
         $.integer,
         $.float,
-        $.function,
         $.string,
         $.boolean,
         $.list,
@@ -352,15 +352,17 @@ module.exports = grammar({
 
     function: $ =>
       seq(
+        '(',
         'fn',
-        '|',
         repeat(
           seq(
             $.identifier,
+            $.type_definition,
             optional(','),
           ),
         ),
-        '|',
+        ')',
+        $.type_definition,
         $.block,
       ),
 

tree-sitter-dust/src/grammar.json

@@ -196,6 +196,10 @@
     "value": {
       "type": "CHOICE",
       "members": [
+        {
+          "type": "SYMBOL",
+          "name": "function"
+        },
         {
           "type": "SYMBOL",
           "name": "integer"
@@ -204,10 +208,6 @@
           "type": "SYMBOL",
           "name": "float"
         },
-        {
-          "type": "SYMBOL",
-          "name": "function"
-        },
         {
           "type": "SYMBOL",
           "name": "string"
@@ -1149,11 +1149,11 @@
       "members": [
         {
           "type": "STRING",
-          "value": "fn"
+          "value": "("
         },
         {
           "type": "STRING",
-          "value": "|"
+          "value": "fn"
         },
         {
           "type": "REPEAT",
@@ -1164,6 +1164,10 @@
                 "type": "SYMBOL",
                 "name": "identifier"
               },
+              {
+                "type": "SYMBOL",
+                "name": "type_definition"
+              },
               {
                 "type": "CHOICE",
                 "members": [
@@ -1181,7 +1185,11 @@
         },
         {
           "type": "STRING",
-          "value": "|"
+          "value": ")"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "type_definition"
         },
         {
           "type": "SYMBOL",

tree-sitter-dust/src/node-types.json

@@ -167,6 +167,10 @@
         {
           "type": "identifier",
           "named": true
+        },
+        {
+          "type": "type_definition",
+          "named": true
         }
       ]
     }
@@ -810,10 +814,6 @@
     "type": "{",
     "named": false
   },
-  {
-    "type": "|",
-    "named": false
-  },
   {
     "type": "||",
     "named": false