Add async statements

README.md

@@ -11,9 +11,8 @@ A basic dust program:
 Dust can do two (or more) things at the same time with effortless concurrency:
 
 ```dust
-(run 
-    (output 'will this one finish first?')
-    (output 'or will this one?'))
+async (output 'will this one finish first?')
+async (output 'or will this one?')
 ```
 
 Dust is an interpreted, general purpose language with first class functions. It is *data-oriented*, with extensive tools to manage structured and relational data. Dust also includes built-in tooling to import and export data in a variety of formats, including JSON, TOML, YAML and CSV.
@@ -172,6 +171,19 @@ print = function <input> {
 }
 ```
 
+### Concurrency
+
+As a language written in Rust, Dust features effortless concurrency anywhere in your code.
+
+```dust
+if (random_integer) % 2 == 0 {
+    run {
+        (output 1 + 1)
+        (output 1 + 1 == 2)
+    }
+}
+```
+
 ## Implementation
 
 Dust is formally defined as a Tree Sitter grammar in the tree-sitter-dust module. Tree sitter generates a parser, written in C, from a set of rules defined in Javascript. Dust itself is a rust binary that calls the C parser using FFI.

examples/clue_solver.ds

@@ -1,12 +1,18 @@
-suspects = ["White", "Green"];
 rooms = ["Library", "Kitchen"];
+suspects = ["White", "Green"];
 weapons = ["Rope", "Lead Pipe"];
 
+show_card = function <card> {
+	(remove rooms card)
+	(remove suspects card)
+	(remove weapons card)
+}
+
 make_guess = function <current_room> {
 	if (length suspects) == 1
 		&& (length rooms) == 1
 		&& (length weapons) == 1
-	then
+	{
 		(output 'It was '
 			+ suspects.0
 			+ ' in the '
@@ -14,8 +20,8 @@ make_guess = function <current_room> {
 			+ ' with the '
 			+ weapons.0
 			+ '!'
-		);
-	else
+		)
+	} else {
 		(output 'I accuse '
 					+ (random suspects)
 					+ ' in the '
@@ -24,3 +30,4 @@ make_guess = function <current_room> {
 					+ (random weapons)
 					+ '!')
 	}
+}

src/abstract_tree/async.rs

@@ -0,0 +1,23 @@
+use serde::{Deserialize, Serialize};
+
+use crate::{AbstractTree, Item};
+
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
+pub struct Async {
+    item: Item,
+}
+
+impl AbstractTree for Async {
+    fn from_syntax_node(source: &str, node: tree_sitter::Node) -> crate::Result<Self> {
+        debug_assert_eq!("async", node.kind());
+
+        let item_node = node.child(2).unwrap();
+        let item = Item::from_syntax_node(source, item_node)?;
+
+        Ok(Async { item })
+    }
+
+    fn run(&self, source: &str, context: &mut crate::VariableMap) -> crate::Result<crate::Value> {
+        self.item.run_parallel(source, context)
+    }
+}

src/abstract_tree/item.rs

@@ -1,5 +1,6 @@
 //! Top-level unit of Dust code.
 
+use rayon::prelude::*;
 use serde::{Deserialize, Serialize};
 use tree_sitter::Node;
 
@@ -19,6 +20,16 @@ impl Item {
     pub fn new(statements: Vec<Statement>) -> Self {
         Self { statements }
     }
+
+    pub fn run_parallel(&self, source: &str, context: &mut VariableMap) -> Result<Value> {
+        self.statements.par_iter().for_each(|statement| {
+            let mut context = context.clone();
+
+            statement.run(source, &mut context);
+        });
+
+        Ok(Value::Empty)
+    }
 }
 
 impl AbstractTree for Item {

src/abstract_tree/mod.rs

@@ -7,6 +7,7 @@
 //! examples.
 
 pub mod assignment;
+pub mod r#async;
 pub mod expression;
 pub mod function_call;
 pub mod identifier;

src/abstract_tree/statement.rs

@@ -2,8 +2,8 @@ use serde::{Deserialize, Serialize};
 use tree_sitter::Node;
 
 use crate::{
-    r#while::While, AbstractTree, Assignment, Error, Expression, IfElse, Match, Result, Value,
-    VariableMap,
+    r#async::Async, r#while::While, AbstractTree, Assignment, Error, Expression, IfElse, Match,
+    Result, Value, VariableMap,
 };
 
 /// Abstract representation of a statement.
@@ -17,6 +17,7 @@ pub enum Statement {
     IfElse(Box<IfElse>),
     Match(Match),
     While(Box<While>),
+    Run(Box<Async>),
 }
 
 impl AbstractTree for Statement {
@@ -41,8 +42,11 @@ impl AbstractTree for Statement {
             "while" => Ok(Statement::While(Box::new(While::from_syntax_node(
                 source, child,
             )?))),
+            "async" => Ok(Statement::Run(Box::new(Async::from_syntax_node(
+                source, child,
+            )?))),
             _ => Err(Error::UnexpectedSyntaxNode {
-                expected: "assignment, expression, if...else or tool",
+                expected: "assignment, expression, if...else, while, tool or async",
                 actual: child.kind(),
                 location: child.start_position(),
                 relevant_source: source[child.byte_range()].to_string(),
@@ -57,6 +61,7 @@ impl AbstractTree for Statement {
             Statement::IfElse(if_else) => if_else.run(source, context),
             Statement::Match(r#match) => r#match.run(source, context),
             Statement::While(r#while) => r#while.run(source, context),
+            Statement::Run(run) => run.run(source, context),
         }
     }
 }

src/abstract_tree/tool.rs

@@ -3,13 +3,14 @@ use std::fs::read_to_string;
 use rand::{random, thread_rng, Rng};
 use serde::{Deserialize, Serialize};
 
-use crate::{Error, Result, Table, Value};
+use crate::{evaluate, Error, Result, Table, Value};
 
 #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
 pub enum Tool {
     Assert,
     AssertEqual,
     Output,
+    Run,
     Read,
     Help,
 
@@ -96,6 +97,14 @@ impl Tool {
                     });
                 }
             }
+            Tool::Run => {
+                Error::expect_tool_argument_amount("run", 1, values.len())?;
+
+                let file_path = values[0].as_string()?;
+                let file_contents = read_to_string(file_path)?;
+
+                evaluate(&file_contents)?
+            }
             Tool::Output => {
                 if values.len() != 1 {
                     return Err(Error::ExpectedToolArgumentAmount {

tree-sitter-dust

@@ -1 +1 @@
-Subproject commit b47907ee26b42990e5170ba9521de5ae66d596ef
+Subproject commit 0f58ea5a7a05d49d99bbe24b9da03eea5249cbd7