feat(jsruntime): async/await (#340)

* feat(jstb): add `--as`

* feat(jsparser): `Module` and `AwaitExpression`

* feat(jsruntime)!: dump only when "1" is set

* style(jsruntime): format

* feat(jsruntime): implement async/await

TODO: enable the scope cleanup checker again
TODO: refactoring

* test(jsruntime): add test cases

* feat(jsruntime): await promise

* feat(jsruntime): top-level await expressions in modules

* feat(jsruntime): AsyncFunctionExpression

* feat(jsruntime): AsyncArrowFunction

* refactor(jsruntime): refactoring

* style(jsruntime): format

* test(jsruntime): reorganize files

* fix(jsparser): StatementList_Await

* test(jsruntime): add test cases

* feat(jsruntime): simplify the scope cleanup checker

* refactor(jsruntime): refactoring

* refactor(jsruntime): refactoring

* fix(jsruntime): support the scope cleanup checker in coroutines

* refactor(jsruntime): pass FunctionId to peer

* refactor(jsruntime): refactoring

* feat(jsruntime): save operands to the scratch buffer

* fix(jsruntime): await_in_if_else.mjs

* refactor(jsruntime): refactoring for the switch statement

* fix(jsruntime): await_in_switch_case.mjs

* style(jsruntime): format

* feat(jsruntime): compute the size of the scratch buffer

* fix(jsruntime): await_in_arguments.mjs

* fix(jsruntime): save closures and promises to the scratch buffer

* fix(jsruntime): await_in_arguments.mjs

* build(deps): update Cargo.lock

* fix(jstb): remove unused crates

* fix(jsparser): remove unused hidden symbols

* refactor(jsruntime): refactoring

* fix(jsruntime): fix a borrow checker issue

* refactor(jsruntime): refactoring

* fix(jsruntime): fix comments

* docs(jsruntime): implementation notes

* refactor(jsruntime): refactoring

* refactor(jsruntime): refactoring

Author: masnagam

Cargo.lock

@@ -12,6 +12,17 @@ struct CommandLine {
     #[command(subcommand)]
     command: Command,
 
+    /// The type of the source text.
+    ///
+    /// Specify `module` explicitly when the source text read from STDIN is parsed as a module.
+    #[arg(
+        global = true,
+        long = "as",
+        default_value = "auto",
+        value_name = "SOURCE_TYPE"
+    )]
+    parse_as: SourceType,
+
     /// Enables the scope cleanup checker.
     #[arg(global = true, long)]
     scope_cleanup_checker: bool,
@@ -65,6 +76,20 @@ struct Run {
     no_optimize: bool,
 }
 
+#[derive(clap::ValueEnum, Clone)]
+enum SourceType {
+    /// Parse as a script if the file extension of the input file is "js".
+    /// Parse as a module if the file extension of the input file is "mjs".
+    /// Otherwise, parse as a script.
+    Auto,
+
+    /// Parse as a script.
+    Script,
+
+    /// Parse as a module.
+    Module,
+}
+
 fn main() -> Result<()> {
     logging::init();
 
@@ -80,9 +105,26 @@ fn main() -> Result<()> {
 
     let source = read_source(cl.source.as_ref())?;
 
+    // This is not a good practice, but we define a macro instead of a function in order to avoid
+    // code clones.  By using the macro, we can avoid additional `use` directives needed for the
+    // return type.
+    macro_rules! parse {
+        ($source:expr, $cl:expr) => {
+            match $cl.parse_as {
+                SourceType::Auto => match $cl.source.as_ref().and_then(|path| path.extension()) {
+                    Some(ext) if ext == "js" => runtime.parse_script($source),
+                    Some(ext) if ext == "mjs" => runtime.parse_module($source),
+                    _ => runtime.parse_script($source),
+                },
+                SourceType::Script => runtime.parse_script($source),
+                SourceType::Module => runtime.parse_module($source),
+            }
+        };
+    }
+
     match cl.command {
         Command::Parse(args) => {
-            let program = runtime.parse_script(&source)?;
+            let program = parse!(&source, cl)?;
             for kind in args.print.chars() {
                 match kind {
                     'f' => {
@@ -99,15 +141,16 @@ fn main() -> Result<()> {
         }
         Command::Compile(args) => {
             runtime.enable_llvmir_labels();
-            let program = runtime.parse_script(&source)?;
+            let program = parse!(&source, cl)?;
             let module = runtime.compile(&program, !args.no_optimize)?;
             module.print(false); // to STDOUT
         }
         Command::Run(args) => {
-            let program = runtime.parse_script(&source)?;
+            let program = parse!(&source, cl)?;
             let module = runtime.compile(&program, !args.no_optimize)?;
-            if let Err(v) = runtime.evaluate(module) {
-                println!("Uncaught {v:?}");
+            match runtime.evaluate(module) {
+                Ok(_) => runtime.run(),
+                Err(v) => println!("Uncaught {v:?}"),
             }
         }
     }

bins/estree/src/builder/actions.yaml

@@ -35,8 +35,8 @@ GOAL_SYMBOLS := \
   ArrowFormalParameters \
   ArrowFormalParameters_Yield \
   ArrowFormalParameters_Await \
-  ArrowFormalParameters_Yield_Await
-
+  ArrowFormalParameters_Yield_Await \
+  AsyncArrowHead
 
 # targets
 

bins/jstb/src/main.rs

@@ -8,14 +8,27 @@ use super::SymbolRegistry;
 
 impl Symbol {
     {%- for symbol in data %}
-    pub const {{ symbol | upper }}: Self = Self({{ loop.index0 + 1 }});
+    {%- if symbol.startsWith('##') %}
+    pub const HIDDEN_{{ symbol | constantCase }}: Self = Self({{ loop.index }});
+    {%- else %}
+    {#- Use `upper` instead of `constantCase` so that 'NaN' is converted into 'NAN'. #}
+    pub const {{ symbol | upper }}: Self = Self({{ loop.index }});
+    {%- endif %}
     {%- endfor %}
+
+    pub fn is_hidden(&self) -> bool {
+        self.0 <= {{ data | select('startsWith', '##') | length }}
+    }
 }
 
 impl SymbolRegistry {
     pub(super) fn register_builtin_symbols(&mut self) {
         {%- for symbol in data %}
+        {%- if symbol.startsWith('##') %}
+        self.register_builtin_symbol(Symbol::HIDDEN_{{ symbol | constantCase }}, "{{ symbol }}");
+        {%- else %}
         self.register_builtin_symbol(Symbol::{{ symbol | upper }}, "{{ symbol }}");
+        {%- endif %}
         {%- endfor %}
     }
 

libs/jsparser/src/parser/Makefile

@@ -1,3 +1,11 @@
+# Hidden symbols must be defined before others.
+# Hidden symbols must start with `##`.
+- '##coroutine'
+- '##promise'
+- '##result'
+- '##error'
+
+# Reserved words defined in the ECMA-262 specification.
 - Infinity
 - NaN
 - async

libs/jsparser/src/symbol/builtins.rs.njk

@@ -10,7 +10,6 @@ pub struct Symbol(u32);
 impl Symbol {
     pub const NONE: Symbol = Symbol(0);
 
-    #[inline]
     pub fn id(&self) -> u32 {
         self.0
     }