Implement matching for enums

src/abstract_tree/enum_pattern.rs

@@ -0,0 +1,70 @@
+use serde::{Deserialize, Serialize};
+use tree_sitter::Node as SyntaxNode;
+
+use crate::{
+    error::{RuntimeError, SyntaxError, ValidationError},
+    AbstractTree, Context, Format, Identifier, Type, Value,
+};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct EnumPattern {
+    name: Identifier,
+    variant: Identifier,
+    inner_identifier: Option<Identifier>,
+}
+
+impl EnumPattern {
+    pub fn name(&self) -> &Identifier {
+        &self.name
+    }
+
+    pub fn variant(&self) -> &Identifier {
+        &self.variant
+    }
+
+    pub fn inner_identifier(&self) -> &Option<Identifier> {
+        &self.inner_identifier
+    }
+}
+
+impl AbstractTree for EnumPattern {
+    fn from_syntax(node: SyntaxNode, source: &str, context: &Context) -> Result<Self, SyntaxError> {
+        SyntaxError::expect_syntax_node(source, "enum_pattern", node)?;
+
+        let enum_name_node = node.child(0).unwrap();
+        let name = Identifier::from_syntax(enum_name_node, source, context)?;
+
+        let enum_variant_node = node.child(2).unwrap();
+        let variant = Identifier::from_syntax(enum_variant_node, source, context)?;
+
+        let inner_identifier = if let Some(child) = node.child(4) {
+            Some(Identifier::from_syntax(child, source, context)?)
+        } else {
+            None
+        };
+
+        Ok(EnumPattern {
+            name,
+            variant,
+            inner_identifier,
+        })
+    }
+
+    fn expected_type(&self, _context: &Context) -> Result<Type, ValidationError> {
+        Ok(Type::None)
+    }
+
+    fn validate(&self, _source: &str, _context: &Context) -> Result<(), ValidationError> {
+        Ok(())
+    }
+
+    fn run(&self, _source: &str, _context: &Context) -> Result<Value, RuntimeError> {
+        Ok(Value::none())
+    }
+}
+
+impl Format for EnumPattern {
+    fn format(&self, _output: &mut String, _indent_level: u8) {
+        todo!()
+    }
+}

src/abstract_tree/match.rs

@@ -3,17 +3,18 @@
 //! Note that this module is called "match" but is escaped as "r#match" because
 //! "match" is a keyword in Rust.
 use serde::{Deserialize, Serialize};
+use tree_sitter::Node as SyntaxNode;
 
 use crate::{
     error::{RuntimeError, SyntaxError, ValidationError},
-    AbstractTree, Context, Expression, Format, Statement, SyntaxNode, Type, Value,
+    AbstractTree, Context, Expression, Format, MatchPattern, Statement, Type, Value,
 };
 
 /// Abstract representation of a match statement.
 #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
 pub struct Match {
     matcher: Expression,
-    options: Vec<(Expression, Statement)>,
+    options: Vec<(MatchPattern, Statement)>,
     fallback: Option<Box<Statement>>,
 }
 
@@ -25,19 +26,15 @@ impl AbstractTree for Match {
         let matcher = Expression::from_syntax(matcher_node, source, context)?;
 
         let mut options = Vec::new();
-        let mut previous_expression = None;
+        let mut previous_pattern = None;
         let mut next_statement_is_fallback = false;
         let mut fallback = None;
 
         for index in 2..node.child_count() {
             let child = node.child(index).unwrap();
 
-            if child.kind() == "*" {
+            if child.kind() == "match_pattern" {
-                next_statement_is_fallback = true;
+                previous_pattern = Some(MatchPattern::from_syntax(child, source, context)?);
-            }
-
-            if child.kind() == "expression" {
-                previous_expression = Some(Expression::from_syntax(child, source, context)?);
             }
 
             if child.kind() == "statement" {
@@ -46,7 +43,7 @@ impl AbstractTree for Match {
                 if next_statement_is_fallback {
                     fallback = Some(Box::new(statement));
                     next_statement_is_fallback = false;
-                } else if let Some(expression) = &previous_expression {
+                } else if let Some(expression) = &previous_pattern {
                     options.push((expression.clone(), statement));
                 }
             }
@@ -83,10 +80,26 @@ impl AbstractTree for Match {
     fn run(&self, source: &str, context: &Context) -> Result<Value, RuntimeError> {
         let matcher_value = self.matcher.run(source, context)?;
 
-        for (expression, statement) in &self.options {
+        for (pattern, statement) in &self.options {
-            let option_value = expression.run(source, context)?;
+            if let (Value::Enum(enum_instance), MatchPattern::EnumPattern(enum_pattern)) =
+                (&matcher_value, pattern)
+            {
+                if enum_instance.name() == enum_pattern.name().inner()
+                    && enum_instance.variant_name() == enum_pattern.variant().inner()
+                {
+                    let statement_context = Context::with_variables_from(context)?;
 
-            if matcher_value == option_value {
+                    if let Some(identifier) = enum_pattern.inner_identifier() {
+                        statement_context
+                            .set_value(identifier.inner().clone(), enum_instance.value().clone())?;
+                    }
+
+                    return statement.run(source, &statement_context);
+                }
+            }
+            let pattern_value = pattern.run(source, context)?;
+
+            if matcher_value == pattern_value {
                 return statement.run(source, context);
             }
         }

src/abstract_tree/match_pattern.rs

@@ -0,0 +1,65 @@
+use serde::{Deserialize, Serialize};
+use tree_sitter::Node as SyntaxNode;
+
+use crate::{
+    error::{RuntimeError, SyntaxError, ValidationError},
+    AbstractTree, Context, EnumPattern, Format, Type, Value, ValueNode,
+};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub enum MatchPattern {
+    EnumPattern(EnumPattern),
+    Value(ValueNode),
+    Wildcard,
+}
+
+impl AbstractTree for MatchPattern {
+    fn from_syntax(node: SyntaxNode, source: &str, context: &Context) -> Result<Self, SyntaxError> {
+        SyntaxError::expect_syntax_node(source, "match_pattern", node)?;
+
+        let child = node.child(0).unwrap();
+        let pattern = match child.kind() {
+            "enum_pattern" => {
+                MatchPattern::EnumPattern(EnumPattern::from_syntax(child, source, context)?)
+            }
+            "value" => MatchPattern::Value(ValueNode::from_syntax(child, source, context)?),
+            "*" => MatchPattern::Wildcard,
+            _ => {
+                return Err(SyntaxError::UnexpectedSyntaxNode {
+                    expected: "enum pattern or value".to_string(),
+                    actual: child.kind().to_string(),
+                    location: child.start_position(),
+                    relevant_source: source[child.byte_range()].to_string(),
+                })
+            }
+        };
+
+        Ok(pattern)
+    }
+
+    fn expected_type(&self, _context: &Context) -> Result<Type, ValidationError> {
+        match self {
+            MatchPattern::EnumPattern(enum_pattern) => enum_pattern.expected_type(_context),
+            MatchPattern::Value(value_node) => value_node.expected_type(_context),
+            MatchPattern::Wildcard => todo!(),
+        }
+    }
+
+    fn validate(&self, _source: &str, _context: &Context) -> Result<(), ValidationError> {
+        Ok(())
+    }
+
+    fn run(&self, _source: &str, _context: &Context) -> Result<Value, RuntimeError> {
+        match self {
+            MatchPattern::EnumPattern(enum_pattern) => enum_pattern.run(_source, _context),
+            MatchPattern::Value(value_node) => value_node.run(_source, _context),
+            MatchPattern::Wildcard => todo!(),
+        }
+    }
+}
+
+impl Format for MatchPattern {
+    fn format(&self, _output: &mut String, _indent_level: u8) {
+        todo!()
+    }
+}

src/abstract_tree/mod.rs

@@ -12,6 +12,7 @@ pub mod assignment_operator;
 pub mod block;
 pub mod command;
 pub mod enum_defintion;
+pub mod enum_pattern;
 pub mod expression;
 pub mod r#for;
 pub mod function_call;
@@ -26,6 +27,7 @@ pub mod logic;
 pub mod logic_operator;
 pub mod map_node;
 pub mod r#match;
+pub mod match_pattern;
 pub mod math;
 pub mod math_operator;
 pub mod new;
@@ -38,12 +40,12 @@ pub mod value_node;
 pub mod r#while;
 
 pub use {
-    assignment::*, assignment_operator::*, block::*, command::*, enum_defintion::*, expression::*,
+    assignment::*, assignment_operator::*, block::*, command::*, enum_defintion::*,
-    function_call::*, function_expression::*, function_node::*, identifier::*, if_else::*,
+    enum_pattern::*, expression::*, function_call::*, function_expression::*, function_node::*,
-    index::*, index_assignment::IndexAssignment, index_expression::*, logic::*, logic_operator::*,
+    identifier::*, if_else::*, index::*, index_assignment::IndexAssignment, index_expression::*,
-    map_node::*, math::*, math_operator::*, new::*, r#as::*, r#for::*, r#match::*, r#type::*,
+    logic::*, logic_operator::*, map_node::*, match_pattern::*, math::*, math_operator::*, new::*,
-    r#while::*, statement::*, struct_definition::*, type_definition::*, type_specification::*,
+    r#as::*, r#for::*, r#match::*, r#type::*, r#while::*, statement::*, struct_definition::*,
-    value_node::*,
+    type_definition::*, type_specification::*, value_node::*,
 };
 
 use serde::{Deserialize, Serialize};

src/value/enum_instance.rs

@@ -1,3 +1,5 @@
+use std::fmt::{self, Display, Formatter};
+
 use crate::Value;
 
 #[derive(Debug, Clone, Eq, PartialEq, PartialOrd, Ord)]
@@ -15,4 +17,22 @@ impl EnumInstance {
             value: Box::new(value),
         }
     }
+
+    pub fn name(&self) -> &String {
+        &self.name
+    }
+
+    pub fn variant_name(&self) -> &String {
+        &self.variant_name
+    }
+
+    pub fn value(&self) -> &Value {
+        &self.value
+    }
+}
+
+impl Display for EnumInstance {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "{}::{}({})", self.name, self.variant_name, self.value)
+    }
 }

src/value/mod.rs

@@ -560,7 +560,7 @@ impl Display for Value {
             Value::Function(function) => write!(f, "{function}"),
             Value::Struct(structure) => write!(f, "{structure}"),
             Value::Range(range) => write!(f, "{}..{}", range.start(), range.end()),
-            Value::Enum(_) => todo!(),
+            Value::Enum(enum_instance) => write!(f, "{enum_instance}"),
         }
     }
 }

tests/match.rs

@@ -1,7 +1,7 @@
 use dust_lang::*;
 
 #[test]
-fn r#match() {
+fn match_value() {
     let test = interpret(
         "
         match 1 {
@@ -32,3 +32,19 @@ fn match_assignment() {
 
     assert_eq!(Value::Boolean(true), test);
 }
+
+#[test]
+fn match_enum() {
+    let result = interpret(
+        "
+        foobar = Option::Some(true)
+        
+        match foobar {
+            Option::None => false,
+            Option::Some(content) => content,
+        }
+        ",
+    );
+
+    assert_eq!(result, Ok(Value::Boolean(true)));
+}

tree-sitter-dust/corpus/match.txt

@@ -16,7 +16,7 @@ match x {
     (match
       (expression
         (identifier))
-      (expression
+      (match_pattern
         (value
           (integer)))
       (statement
@@ -25,10 +25,43 @@ match x {
             (expression
               (value
                 (boolean))))))
-      (expression
+      (match_pattern
         (value
           (integer)))
       (statement
         (expression
           (value
             (boolean)))))))
+
+================================================================================
+Match Enum
+================================================================================
+
+match foobar {
+  FooBar::Foo => true
+  FooBar::Bar => false
+}
+
+--------------------------------------------------------------------------------
+
+(root
+  (statement
+    (match
+      (expression
+        (identifier))
+      (match_pattern
+        (enum_pattern
+          (identifier)
+          (identifier)))
+      (statement
+        (expression
+          (value
+            (boolean))))
+      (match_pattern
+        (enum_pattern
+          (identifier)
+          (identifier)))
+      (statement
+        (expression
+          (value
+            (boolean)))))))

tree-sitter-dust/grammar.js

@@ -290,7 +290,7 @@ module.exports = grammar({
           '{',
           repeat1(
             seq(
-              choice($.expression, '*'),
+              $.match_pattern,
               '=>',
               $.statement,
               optional(','),
@@ -300,6 +300,26 @@ module.exports = grammar({
         ),
       ),
 
+    match_pattern: $ =>
+      choice(
+        $.enum_pattern,
+        $.value,
+        '*',
+      ),
+
+    enum_pattern: $ =>
+      prec(
+        1,
+        seq(
+          $.identifier,
+          '::',
+          $.identifier,
+          optional(
+            seq('(', $.identifier, ')'),
+          ),
+        ),
+      ),
+
     while: $ =>
       seq(
         'while',

tree-sitter-dust/src/grammar.json

@@ -855,19 +855,10 @@
             "type": "REPEAT1",
             "content": {
               "type": "SEQ",
-              "members": [
-                {
-                  "type": "CHOICE",
               "members": [
                 {
                   "type": "SYMBOL",
-                      "name": "expression"
+                  "name": "match_pattern"
-                    },
-                    {
-                      "type": "STRING",
-                      "value": "*"
-                    }
-                  ]
                 },
                 {
                   "type": "STRING",
@@ -899,6 +890,69 @@
         ]
       }
     },
+    "match_pattern": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "enum_pattern"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "value"
+        },
+        {
+          "type": "STRING",
+          "value": "*"
+        }
+      ]
+    },
+    "enum_pattern": {
+      "type": "PREC",
+      "value": 1,
+      "content": {
+        "type": "SEQ",
+        "members": [
+          {
+            "type": "SYMBOL",
+            "name": "identifier"
+          },
+          {
+            "type": "STRING",
+            "value": "::"
+          },
+          {
+            "type": "SYMBOL",
+            "name": "identifier"
+          },
+          {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "SEQ",
+                "members": [
+                  {
+                    "type": "STRING",
+                    "value": "("
+                  },
+                  {
+                    "type": "SYMBOL",
+                    "name": "identifier"
+                  },
+                  {
+                    "type": "STRING",
+                    "value": ")"
+                  }
+                ]
+              },
+              {
+                "type": "BLANK"
+              }
+            ]
+          }
+        ]
+      }
+    },
     "while": {
       "type": "SEQ",
       "members": [

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

@@ -170,6 +170,21 @@
       ]
     }
   },
+  {
+    "type": "enum_pattern",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": true,
+      "types": [
+        {
+          "type": "identifier",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "expression",
     "named": true,
@@ -495,6 +510,10 @@
           "type": "expression",
           "named": true
         },
+        {
+          "type": "match_pattern",
+          "named": true
+        },
         {
           "type": "statement",
           "named": true
@@ -502,6 +521,25 @@
       ]
     }
   },
+  {
+    "type": "match_pattern",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": false,
+      "required": false,
+      "types": [
+        {
+          "type": "enum_pattern",
+          "named": true
+        },
+        {
+          "type": "value",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "math",
     "named": true,