Improve soundness of Map type

Cargo.lock

@@ -468,7 +468,6 @@ dependencies = [
  "comfy-table",
  "csv",
  "git2",
- "json",
  "rand",
  "rayon",
  "reqwest",
@@ -909,12 +908,6 @@ dependencies = [
  "wasm-bindgen",
 ]
 
-[[package]]
-name = "json"
-version = "0.12.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "078e285eafdfb6c4b434e0d31e8cfcb5115b651496faca5749b88fafd4f23bfd"
-
 [[package]]
 name = "kv-log-macro"
 version = "1.0.7"

Cargo.toml

@@ -17,7 +17,6 @@ clap = { version = "4.4.4", features = ["derive"] }
 comfy-table = "7.0.1"
 csv = "1.2.2"
 git2 = "0.18.1"
-json = "0.12.4"
 rand = "0.8.5"
 rayon = "1.8.0"
 reqwest = { version = "0.11.20", features = ["blocking", "json"] }

examples/async_download.ds

@@ -1,11 +1,13 @@
-data = async { {
+raw_data = async {
+	{
 		cast = (download "https://api.sampleapis.com/futurama/cast")
 		characters = (download "https://api.sampleapis.com/futurama/characters")	
 		episodes = (download "https://api.sampleapis.com/futurama/episodes")
-} }
+	}
+}
 
 cast_len = (length (from_json data:cast))
 characters_len = (length (from_json data:characters))
 episodes_len = (length (from_json data:episodes))
 
-(output [cast_len, characters_len, episodes_len ])
+(output [cast_len, characters_len, episodes_len])

src/abstract_tree/assignment.rs

@@ -50,11 +50,11 @@ impl AbstractTree for Assignment {
     fn run(&self, source: &str, context: &mut Map) -> Result<Value> {
         let key = self.identifier.inner().clone();
         let value = self.statement.run(source, context)?;
-        let mut context = context.variables_mut();
+        let mut variables = context.variables_mut()?;
 
         let new_value = match self.operator {
             AssignmentOperator::PlusEqual => {
-                if let Some(mut previous_value) = context.get(&key).cloned() {
+                if let Some(mut previous_value) = variables.get(&key).cloned() {
                     previous_value += value;
                     previous_value
                 } else {
@@ -62,7 +62,7 @@ impl AbstractTree for Assignment {
                 }
             }
             AssignmentOperator::MinusEqual => {
-                if let Some(mut previous_value) = context.get(&key).cloned() {
+                if let Some(mut previous_value) = variables.get(&key).cloned() {
                     previous_value -= value;
                     previous_value
                 } else {
@@ -72,7 +72,7 @@ impl AbstractTree for Assignment {
             AssignmentOperator::Equal => value,
         };
 
-        context.insert(key, new_value);
+        variables.insert(key, new_value);
 
         Ok(Value::Empty)
     }

src/abstract_tree/built_in_function.rs

@@ -317,7 +317,7 @@ impl AbstractTree for BuiltInFunction {
                 let value = expression.run(source, context)?;
                 let length = match value {
                     Value::List(list) => list.items().len(),
-                    Value::Map(map) => map.len(),
+                    Value::Map(map) => map.variables()?.len(),
                     Value::Table(table) => table.len(),
                     Value::String(string) => string.chars().count(),
                     Value::Function(_) => todo!(),
@@ -405,7 +405,7 @@ impl AbstractTree for BuiltInFunction {
                 let metadata_output = Map::new();
 
                 {
-                    let mut metadata_variables = metadata_output.variables_mut();
+                    let mut metadata_variables = metadata_output.variables_mut()?;
 
                     metadata_variables.insert("type".to_string(), Value::String(file_type));
                     metadata_variables.insert("size".to_string(), Value::Integer(size));

src/abstract_tree/filter.rs

@@ -45,7 +45,7 @@ impl AbstractTree for Filter {
             Some(expression) => Some(expression.run(source, context)?.as_integer()? as usize),
             None => None,
         };
-        let loop_context = Map::clone_from(context);
+        let loop_context = Map::clone_from(context)?;
 
         values.par_iter().try_for_each(|value| {
             if let Some(max) = count {
@@ -57,7 +57,7 @@ impl AbstractTree for Filter {
             let mut iter_context = loop_context.clone();
 
             iter_context
-                .variables_mut()
+                .variables_mut()?
                 .insert(key.clone(), value.clone());
 
             let should_include = self

src/abstract_tree/find.rs

@@ -32,12 +32,12 @@ impl AbstractTree for Find {
         let value = self.expression.run(source, context)?;
         let values = value.as_list()?.items();
         let key = self.identifier.inner();
-        let mut context = context.clone();
+        let mut variables = context.variables_mut()?;
 
         for value in values.iter() {
-            context.variables_mut().insert(key.clone(), value.clone());
+            variables.insert(key.clone(), value.clone());
 
-            let should_return = self.item.run(source, &mut context)?.as_boolean()?;
+            let should_return = self.item.run(source, &mut context.clone())?.as_boolean()?;
 
             if should_return {
                 return Ok(value.clone());

src/abstract_tree/for.rs

@@ -49,25 +49,25 @@ impl AbstractTree for For {
         let expression_run = self.collection.run(source, context)?;
         let values = expression_run.as_list()?.items();
         let key = self.item_id.inner();
-        let mut loop_context = Map::clone_from(context);
+        let loop_context = Map::clone_from(context)?;
 
         if self.is_async {
             values.par_iter().try_for_each(|value| {
                 let mut iter_context = loop_context.clone();
 
                 iter_context
-                    .variables_mut()
+                    .variables_mut()?
                     .insert(key.clone(), value.clone());
 
                 self.block.run(source, &mut iter_context).map(|_value| ())
             })?;
         } else {
-            for value in values.iter() {
-                loop_context
-                    .variables_mut()
-                    .insert(key.clone(), value.clone());
+            let mut variables = loop_context.variables_mut()?;
 
-                self.block.run(source, &mut loop_context)?;
+            for value in values.iter() {
+                variables.insert(key.clone(), value.clone());
+
+                self.block.run(source, &mut loop_context.clone())?;
             }
         }
 

src/abstract_tree/function_call.rs

@@ -53,21 +53,22 @@ impl AbstractTree for FunctionCall {
             FunctionCall::ContextDefined { name, arguments } => (name, arguments),
         };
 
-        let definition = if let Some(value) = context.variables().get(name.inner()) {
+        let definition = if let Some(value) = context.variables()?.get(name.inner()) {
             value.as_function().cloned()?
         } else {
             return Err(Error::FunctionIdentifierNotFound(name.clone()));
         };
-        let mut function_context = Map::clone_from(context);
+        let mut function_context = Map::clone_from(context)?;
 
         if let Some(parameters) = definition.identifiers() {
             let parameter_expression_pairs = parameters.iter().zip(arguments.iter());
+            let mut variables = function_context.variables_mut()?;
 
             for (identifier, expression) in parameter_expression_pairs {
                 let key = identifier.clone().take_inner();
                 let value = expression.run(source, context)?;
 
-                function_context.variables_mut().insert(key, value);
+                variables.insert(key, value);
             }
         }
 

src/abstract_tree/identifier.rs

@@ -30,7 +30,7 @@ impl AbstractTree for Identifier {
     }
 
     fn run(&self, _source: &str, context: &mut Map) -> Result<Value> {
-        if let Some(value) = context.variables().get(&self.0) {
+        if let Some(value) = context.variables()?.get(&self.0) {
             Ok(value.clone())
         } else {
             Err(Error::VariableIdentifierNotFound(self.inner().clone()))

src/abstract_tree/identifier_assignment.rs

@@ -0,0 +1,79 @@
+use serde::{Deserialize, Serialize};
+use tree_sitter::Node;
+
+use crate::{AbstractTree, Error, Identifier, Map, Result, Statement, Value};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct IdentifierAssignment {
+    identifier: Identifier,
+    operator: AssignmentOperator,
+    statement: Statement,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub enum AssignmentOperator {
+    Equal,
+    PlusEqual,
+    MinusEqual,
+}
+
+impl AbstractTree for IdentifierAssignment {
+    fn from_syntax_node(source: &str, node: Node) -> Result<Self> {
+        let identifier_node = node.child(0).unwrap();
+        let identifier = Identifier::from_syntax_node(source, identifier_node)?;
+
+        let operator_node = node.child(1).unwrap().child(0).unwrap();
+        let operator = match operator_node.kind() {
+            "=" => AssignmentOperator::Equal,
+            "+=" => AssignmentOperator::PlusEqual,
+            "-=" => AssignmentOperator::MinusEqual,
+            _ => {
+                return Err(Error::UnexpectedSyntaxNode {
+                    expected: "=, += or -=",
+                    actual: operator_node.kind(),
+                    location: operator_node.start_position(),
+                    relevant_source: source[operator_node.byte_range()].to_string(),
+                })
+            }
+        };
+
+        let statement_node = node.child(2).unwrap();
+        let statement = Statement::from_syntax_node(source, statement_node)?;
+
+        Ok(IdentifierAssignment {
+            identifier,
+            operator,
+            statement,
+        })
+    }
+
+    fn run(&self, source: &str, context: &mut Map) -> Result<Value> {
+        let key = self.identifier.inner().clone();
+        let value = self.statement.run(source, context)?;
+        let mut context = context.variables_mut();
+
+        let new_value = match self.operator {
+            AssignmentOperator::PlusEqual => {
+                if let Some(mut previous_value) = context.get(&key).cloned() {
+                    previous_value += value;
+                    previous_value
+                } else {
+                    Value::Empty
+                }
+            }
+            AssignmentOperator::MinusEqual => {
+                if let Some(mut previous_value) = context.get(&key).cloned() {
+                    previous_value -= value;
+                    previous_value
+                } else {
+                    Value::Empty
+                }
+            }
+            AssignmentOperator::Equal => value,
+        };
+
+        context.insert(key, new_value);
+
+        Ok(Value::Empty)
+    }
+}

src/abstract_tree/index_assignment.rs

@@ -0,0 +1,62 @@
+use serde::{Deserialize, Serialize};
+use tree_sitter::Node;
+
+use crate::{AbstractTree, Error, Index, Map, Result, Statement, Value};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct IndexAssignment {
+    index: Index,
+    operator: AssignmentOperator,
+    statement: Statement,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub enum AssignmentOperator {
+    Equal,
+    PlusEqual,
+    MinusEqual,
+}
+
+impl AbstractTree for IndexAssignment {
+    fn from_syntax_node(source: &str, node: Node) -> Result<Self> {
+        let index_node = node.child(0).unwrap();
+        let index = Index::from_syntax_node(source, index_node)?;
+
+        let operator_node = node.child(1).unwrap().child(0).unwrap();
+        let operator = match operator_node.kind() {
+            "=" => AssignmentOperator::Equal,
+            "+=" => AssignmentOperator::PlusEqual,
+            "-=" => AssignmentOperator::MinusEqual,
+            _ => {
+                return Err(Error::UnexpectedSyntaxNode {
+                    expected: "=, += or -=",
+                    actual: operator_node.kind(),
+                    location: operator_node.start_position(),
+                    relevant_source: source[operator_node.byte_range()].to_string(),
+                })
+            }
+        };
+
+        let statement_node = node.child(2).unwrap();
+        let statement = Statement::from_syntax_node(source, statement_node)?;
+
+        Ok(IndexAssignment {
+            index,
+            operator,
+            statement,
+        })
+    }
+
+    fn run(&self, source: &str, context: &mut Map) -> Result<Value> {
+        let mut left = self.index.run(source, context)?;
+        let right = self.statement.run(source, context)?;
+
+        match self.operator {
+            AssignmentOperator::PlusEqual => left += right,
+            AssignmentOperator::MinusEqual => left -= right,
+            AssignmentOperator::Equal => left = right,
+        }
+
+        Ok(Value::Empty)
+    }
+}

src/abstract_tree/insert.rs

@@ -36,7 +36,7 @@ impl AbstractTree for Insert {
         }
 
         context
-            .variables_mut()
+            .variables_mut()?
             .insert(table_name, Value::Table(table));
 
         Ok(Value::Empty)

src/abstract_tree/remove.rs

@@ -33,11 +33,15 @@ impl AbstractTree for Remove {
         let mut values = value.as_list()?.items_mut();
         let key = self.item_id.inner();
         let mut should_remove_index = None;
+        let mut variables = context.variables_mut()?;
 
         values.iter().enumerate().try_for_each(|(index, value)| {
-            context.variables_mut().insert(key.clone(), value.clone());
+            variables.insert(key.clone(), value.clone());
 
-            let should_remove = self.predicate.run(source, context)?.as_boolean()?;
+            let should_remove = self
+                .predicate
+                .run(source, &mut context.clone())?
+                .as_boolean()?;
 
             if should_remove {
                 should_remove_index = Some(index);

src/abstract_tree/select.rs

@@ -60,14 +60,13 @@ impl AbstractTree for Select {
 
         for row in old_table.rows() {
             let mut new_row = Vec::new();
-            let mut row_context = Map::new();
+            let row_context = Map::new();
+            let mut row_variables = row_context.variables_mut()?;
 
             for (i, value) in row.iter().enumerate() {
                 let column_name = old_table.headers().get(i).unwrap();
 
-                row_context
-                    .variables_mut()
-                    .insert(column_name.clone(), value.clone());
+                row_variables.insert(column_name.clone(), value.clone());
 
                 let new_table_column_index =
                     new_table
@@ -91,7 +90,9 @@ impl AbstractTree for Select {
             }
 
             if let Some(where_clause) = &self.predicate {
-                let should_include = where_clause.run(source, &mut row_context)?.as_boolean()?;
+                let should_include = where_clause
+                    .run(source, &mut row_context.clone())?
+                    .as_boolean()?;
 
                 if should_include {
                     new_table.insert(new_row)?;

src/abstract_tree/transform.rs

@@ -36,13 +36,15 @@ impl AbstractTree for Transform {
         let new_values = values
             .par_iter()
             .map(|value| {
-                let mut iter_context = Map::new();
+                let iter_context = Map::new();
+                let mut iter_variables = match iter_context.variables_mut() {
+                    Ok(variables) => variables,
+                    Err(_) => return Value::Empty,
+                };
 
-                iter_context
-                    .variables_mut()
-                    .insert(key.clone(), value.clone());
+                iter_variables.insert(key.clone(), value.clone());
 
-                let item_run = self.item.run(source, &mut iter_context);
+                let item_run = self.item.run(source, &mut iter_context.clone());
 
                 match item_run {
                     Ok(value) => value,

src/abstract_tree/value_node.rs

@@ -168,10 +168,14 @@ impl AbstractTree for ValueNode {
             ValueType::Map(nodes) => {
                 let map = Map::new();
 
+                {
+                    let mut variables = map.variables_mut()?;
+
                     for (key, node) in nodes {
                         let value = node.run(source, context)?;
 
-                    map.variables_mut().insert(key.clone(), value);
+                        variables.insert(key.clone(), value);
+                    }
                 }
 
                 Value::Map(map)

src/abstract_tree/yield.rs

@@ -0,0 +1,28 @@
+use serde::{Deserialize, Serialize};
+use tree_sitter::Node;
+
+use crate::{AbstractTree, Expression, Function, FunctionCall, Result, Value, ValueNode};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct Yield {
+    input: Expression,
+    call: FunctionCall,
+}
+
+impl AbstractTree for Yield {
+    fn from_syntax_node(source: &str, node: Node) -> Result<Self> {
+        let input_node = node.child(0).unwrap();
+        let input = Expression::from_syntax_node(source, input_node)?;
+
+        let call_node = node.child(1).unwrap();
+        let call = FunctionCall::from_syntax_node(source, call_node)?;
+
+        Ok(Yield { input, call })
+    }
+
+    fn run(&self, source: &str, context: &mut crate::Map) -> Result<Value> {
+        let target = self.input.run(source, context)?.as_function()?;
+
+        self.call.run(, )
+    }
+}

src/error.rs

@@ -5,7 +5,7 @@
 
 use crate::{value::Value, Identifier};
 
-use std::{fmt, io, time, string::FromUtf8Error, num::ParseFloatError};
+use std::{fmt, io, time, string::FromUtf8Error, num::ParseFloatError, sync::PoisonError};
 
 pub type Result<T> = std::result::Result<T, Error>;
 
@@ -145,6 +145,12 @@ impl Error {
     }
 }
 
+impl<T> From<PoisonError<T>> for Error {
+    fn from(value: PoisonError<T>) -> Self {
+        Error::ToolFailure(value.to_string())
+    }
+}
+
 impl From<FromUtf8Error> for Error {
     fn from(value: FromUtf8Error) -> Self {
         Error::ToolFailure(value.to_string())
@@ -163,12 +169,6 @@ impl From<csv::Error> for Error {
     }
 }
 
-impl From<json::Error> for Error {
-    fn from(value: json::Error) -> Self {
-        Error::ToolFailure(value.to_string())
-    }
-}
-
 impl From<io::Error> for Error {
     fn from(value: std::io::Error) -> Self {
         Error::ToolFailure(value.to_string())

src/evaluator.rs

@@ -153,10 +153,12 @@ mod tests {
     fn evaluate_map() {
         let map = Map::new();
 
-        map.variables_mut()
-            .insert("x".to_string(), Value::Integer(1));
-        map.variables_mut()
-            .insert("foo".to_string(), Value::String("bar".to_string()));
+        {
+            let mut variables = map.variables_mut().unwrap();
+
+            variables.insert("x".to_string(), Value::Integer(1));
+            variables.insert("foo".to_string(), Value::String("bar".to_string()));
+        }
 
         assert_eq!(evaluate("{ x = 1, foo = 'bar' }"), Ok(Value::Map(map)));
     }

src/main.rs

@@ -55,6 +55,7 @@ async fn main() {
     if let Some(input) = args.input {
         context
             .variables_mut()
+            .unwrap()
             .insert("input".to_string(), Value::String(input));
     }
 
@@ -63,6 +64,7 @@ async fn main() {
 
         context
             .variables_mut()
+            .unwrap()
             .insert("input".to_string(), Value::String(file_contents));
     }
 

src/value/map.rs

@@ -6,7 +6,7 @@ use std::{
     sync::{Arc, RwLock, RwLockReadGuard, RwLockWriteGuard},
 };
 
-use crate::{value::Value, List, Table};
+use crate::{value::Value, List, Result, Table};
 
 /// A collection dust variables comprised of key-value pairs.
 ///
@@ -25,34 +25,24 @@ impl Map {
         }
     }
 
-    pub fn clone_from(other: &Self) -> Self {
+    pub fn clone_from(other: &Self) -> Result<Self> {
         let mut new_map = BTreeMap::new();
 
-        for (key, value) in other.variables().iter() {
+        for (key, value) in other.variables()?.iter() {
             new_map.insert(key.clone(), value.clone());
         }
 
-        Map {
+        Ok(Map {
             variables: Arc::new(RwLock::new(new_map)),
-        }
+        })
     }
 
-    pub fn variables(&self) -> RwLockReadGuard<BTreeMap<String, Value>> {
-        self.variables.read().unwrap()
+    pub fn variables(&self) -> Result<RwLockReadGuard<BTreeMap<String, Value>>> {
+        Ok(self.variables.read()?)
     }
 
-    pub fn variables_mut(&self) -> RwLockWriteGuard<BTreeMap<String, Value>> {
-        self.variables.write().unwrap()
-    }
-
-    /// Returns the number of stored variables.
-    pub fn len(&self) -> usize {
-        self.variables.read().unwrap().len()
-    }
-
-    /// Returns true if the length is zero.
-    pub fn is_empty(&self) -> bool {
-        self.variables.read().unwrap().is_empty()
+    pub fn variables_mut(&self) -> Result<RwLockWriteGuard<BTreeMap<String, Value>>> {
+        Ok(self.variables.write()?)
     }
 }
 
@@ -104,12 +94,12 @@ impl Display for Map {
     }
 }
 
-impl From<&Table> for Map {
-    fn from(value: &Table) -> Self {
+impl From<&Table> for Result<Map> {
+    fn from(value: &Table) -> Result<Map> {
         let map = Map::new();
 
         for (row_index, row) in value.rows().iter().enumerate() {
-            map.variables_mut()
+            map.variables_mut()?
                 .insert(
                     row_index.to_string(),
                     Value::List(List::with_items(row.clone())),
@@ -117,7 +107,7 @@ impl From<&Table> for Map {
                 .unwrap();
         }
 
-        map
+        Ok(map)
     }
 }
 

src/value/mod.rs

@@ -4,7 +4,6 @@ use crate::{
     Function, List, Map, Table, ValueType,
 };
 
-use json::JsonValue;
 use serde::{
     de::{MapAccess, SeqAccess, Visitor},
     ser::SerializeTuple,
@@ -207,7 +206,7 @@ impl Value {
         match self {
             Value::Table(table) => Ok(table.clone()),
             Value::List(list) => Ok(Table::from(list)),
-            Value::Map(map) => Ok(Table::from(map)),
+            Value::Map(map) => Result::from(map),
             value => Err(Error::ExpectedTable {
                 actual: value.clone(),
             }),
@@ -496,82 +495,6 @@ impl From<()> for Value {
     }
 }
 
-impl TryFrom<JsonValue> for Value {
-    type Error = Error;
-
-    fn try_from(json_value: JsonValue) -> Result<Self> {
-        use JsonValue::*;
-
-        match json_value {
-            Null => Ok(Value::Empty),
-            Short(short) => Ok(Value::String(short.to_string())),
-            String(string) => Ok(Value::String(string)),
-            Number(number) => Ok(Value::Float(f64::from(number))),
-            Boolean(boolean) => Ok(Value::Boolean(boolean)),
-            Object(object) => {
-                let map = Map::new();
-
-                for (key, node_value) in object.iter() {
-                    let value = Value::try_from(node_value)?;
-
-                    map.variables_mut().insert(key.to_string(), value);
-                }
-
-                Ok(Value::Map(map))
-            }
-            Array(array) => {
-                let mut values = Vec::new();
-
-                for json_value in array {
-                    let value = Value::try_from(json_value)?;
-
-                    values.push(value);
-                }
-
-                Ok(Value::List(List::with_items(values)))
-            }
-        }
-    }
-}
-
-impl TryFrom<&JsonValue> for Value {
-    type Error = Error;
-
-    fn try_from(json_value: &JsonValue) -> Result<Self> {
-        use JsonValue::*;
-
-        match json_value {
-            Null => Ok(Value::Empty),
-            Short(short) => Ok(Value::String(short.to_string())),
-            String(string) => Ok(Value::String(string.clone())),
-            Number(number) => Ok(Value::Float(f64::from(*number))),
-            Boolean(boolean) => Ok(Value::Boolean(*boolean)),
-            Object(object) => {
-                let map = Map::new();
-
-                for (key, node_value) in object.iter() {
-                    let value = Value::try_from(node_value)?;
-
-                    map.variables_mut().insert(key.to_string(), value);
-                }
-
-                Ok(Value::Map(map))
-            }
-            Array(array) => {
-                let mut values = Vec::new();
-
-                for json_value in array {
-                    let value = Value::try_from(json_value)?;
-
-                    values.push(value);
-                }
-
-                Ok(Value::List(List::with_items(values)))
-            }
-        }
-    }
-}
-
 impl TryFrom<Value> for String {
     type Error = Error;
 
@@ -842,8 +765,12 @@ impl<'de> Visitor<'de> for ValueVisitor {
     {
         let map = Map::new();
 
+        {
+            let mut variables = map.variables_mut().unwrap();
+
             while let Some((key, value)) = access.next_entry()? {
-            map.variables_mut().insert(key, value);
+                variables.insert(key, value);
+            }
         }
 
         Ok(Value::Map(map))

src/value/table.rs

@@ -158,7 +158,7 @@ impl Display for Table {
 
                         string
                     }
-                    Value::Map(map) => format!("Map ({} items)", map.len()),
+                    Value::Map(map) => format!("Map ({} items)", map.variables().unwrap().len()),
                     Value::Table(table) => format!("Table ({} items)", table.len()),
                     Value::Function(_) => "Function".to_string(),
                     Value::Empty => "Empty".to_string(),
@@ -233,7 +233,7 @@ impl From<&Value> for Table {
             }
             Value::List(list) => Self::from(list),
             Value::Empty => Table::new(Vec::with_capacity(0)),
-            Value::Map(map) => Self::from(map),
+            Value::Map(map) => Result::<Table>::from(map).unwrap(),
             Value::Table(table) => table.clone(),
             Value::Function(function) => {
                 let mut table = Table::new(vec!["function".to_string()]);
@@ -280,39 +280,35 @@ impl From<&mut List> for Table {
     }
 }
 
-impl From<Map> for Table {
+impl From<Map> for Result<Table> {
     fn from(map: Map) -> Self {
-        let variables = map.variables();
+        let variables = map.variables()?;
         let keys = variables.keys().cloned().collect();
         let values = variables.values().cloned().collect();
         let mut table = Table::new(keys);
 
-        table
-            .insert(values)
-            .expect("Failed to create Table from Map. This is a no-op.");
+        table.insert(values)?;
 
-        table
+        Ok(table)
     }
 }
 
-impl From<&Map> for Table {
+impl From<&Map> for Result<Table> {
     fn from(map: &Map) -> Self {
-        let variables = map.variables();
+        let variables = map.variables()?;
         let keys = variables.keys().cloned().collect();
         let values = variables.values().cloned().collect();
         let mut table = Table::new(keys);
 
-        table
-            .insert(values)
-            .expect("Failed to create Table from Map. This is a no-op.");
+        table.insert(values)?;
 
-        table
+        Ok(table)
     }
 }
 
-impl From<&mut Map> for Table {
+impl From<&mut Map> for Result<Table> {
     fn from(map: &mut Map) -> Self {
-        let variables = map.variables();
+        let variables = map.variables()?;
         let keys = variables.keys().cloned().collect();
         let values = variables.values().cloned().collect();
         let mut table = Table::new(keys);
@@ -321,7 +317,7 @@ impl From<&mut Map> for Table {
             .insert(values)
             .expect("Failed to create Table from Map. This is a no-op.");
 
-        table
+        Ok(table)
     }
 }
 

src/value/value_type.rs

@@ -114,7 +114,7 @@ impl From<&Value> for ValueType {
             Value::Map(map) => {
                 let mut value_nodes = BTreeMap::new();
 
-                for (key, value) in map.variables().iter() {
+                for (key, value) in map.variables().unwrap().iter() {
                     let value_type = value.value_type();
                     let value_node = ValueNode::new(value_type, 0, 0);
                     let statement = Statement::Expression(Expression::Value(value_node));

tree-sitter-dust/src/grammar.json

@@ -706,20 +706,11 @@
     },
     "assignment": {
       "type": "SEQ",
-      "members": [
-        {
-          "type": "CHOICE",
       "members": [
         {
           "type": "SYMBOL",
           "name": "identifier"
         },
-            {
-              "type": "SYMBOL",
-              "name": "index"
-            }
-          ]
-        },
         {
           "type": "SYMBOL",
           "name": "assignment_operator"

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

@@ -15,10 +15,6 @@
           "type": "identifier",
           "named": true
         },
-        {
-          "type": "index",
-          "named": true
-        },
         {
           "type": "statement",
           "named": true