diff --git a/Cargo.toml b/Cargo.toml
index 033c1ab..312fbc8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,7 @@
 name = "dust-lang"
 description = "Data-Oriented Programming Language"
 version = "0.3.5"
-repository = "https://github.com/tree-sitter/tree-sitter-dust"
+repository = "https://git.jeffa.io/jeff/dust.git"
 edition = "2021"
 license = "MIT"
 
@@ -10,6 +10,11 @@ license = "MIT"
 name = "dust"
 path = "src/main.rs"
 
+[profile.dev]
+opt-level = 1
+[profile.dev.package."*"]
+opt-level = 3
+
 [dependencies]
 ansi_term = "0.12.1"
 async-std = { version = "1.12.0", features = ["attributes"] }
diff --git a/src/abstract_tree/built_in_function.rs b/src/abstract_tree/built_in_function.rs
index 43fe7c1..2d8ce99 100644
--- a/src/abstract_tree/built_in_function.rs
+++ b/src/abstract_tree/built_in_function.rs
@@ -31,7 +31,7 @@ pub enum BuiltInFunction {
     Append(Vec<Expression>),
     Metadata(Expression),
     Move(Vec<Expression>),
-    Read(Expression),
+    Read(Option<Expression>),
     Remove(Expression),
     Write(Vec<Expression>),
 
@@ -155,8 +155,11 @@ impl AbstractTree for BuiltInFunction {
                 BuiltInFunction::Move(expressions)
             }
             "read" => {
-                let expression_node = node.child(1).unwrap();
-                let expression = Expression::from_syntax_node(source, expression_node)?;
+                let expression = if let Some(node) = node.child(1) {
+                    Some(Expression::from_syntax_node(source, node)?)
+                } else {
+                    None
+                };
 
                 BuiltInFunction::Read(expression)
             }
@@ -431,8 +434,13 @@ impl AbstractTree for BuiltInFunction {
                 Ok(Value::Empty)
             }
             BuiltInFunction::Read(expression) => {
-                let path_value = expression.run(source, context)?;
-                let path = PathBuf::from(path_value.as_string()?);
+                let path = if let Some(expression) = expression {
+                    let path_value = expression.run(source, context)?;
+
+                    PathBuf::from(path_value.as_string()?)
+                } else {
+                    PathBuf::from(".")
+                };
                 let content = if path.is_dir() {
                     let dir = read_dir(&path)?;
                     let mut contents = Vec::new();
diff --git a/tree-sitter-dust/grammar.js b/tree-sitter-dust/grammar.js
index ff98969..3d03f65 100644
--- a/tree-sitter-dust/grammar.js
+++ b/tree-sitter-dust/grammar.js
@@ -264,7 +264,7 @@ module.exports = grammar({
       field('body', $.block),
     ),
 
-    function_call: $ => prec.right(seq(
+    function_call: $ => prec.right(1, seq(
       '(',
       choice(
         $.built_in_function,
diff --git a/tree-sitter-dust/src/grammar.json b/tree-sitter-dust/src/grammar.json
index 142d727..1dacf47 100644
--- a/tree-sitter-dust/src/grammar.json
+++ b/tree-sitter-dust/src/grammar.json
@@ -1108,7 +1108,7 @@
     },
     "function_call": {
       "type": "PREC_RIGHT",
-      "value": 0,
+      "value": 1,
       "content": {
         "type": "SEQ",
         "members": [