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Promisify up through source text module record's Evaluate() #15

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Promisify up through source text module record's Evaluate() #15

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1547cde
Small style tweak in ModuleExecution
domenic Apr 23, 2018
ec0135b
Propogate promise-ness to InnerModuleEvaluation
domenic Apr 23, 2018
de599b0
Propagate the promise-ness to stmr.Evaluate()
domenic Apr 23, 2018
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171 changes: 110 additions & 61 deletions spec.html
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Expand Up @@ -40,77 +40,126 @@ <h1><ins>AsyncBlockStart ( _promiseCapability_, _asyncBody_, _asyncContext_ )</i
</emu-alg>
</emu-clause>

<emu-clause id="sec-innermoduleevaluation" aoid="InnerModuleEvaluation">
<h1>InnerModuleEvaluation( _module_, _stack_, _index_ )</h1>
<emu-clause id="sec-moduleevaluation">
<h1>Evaluate( ) Concrete Method</h1>

<p>The InnerModuleEvaluation abstract operation is used by Evaluate to perform the actual evaluation process for the Source Text Module Record _module_, as well as recursively on all other modules in the dependency graph. The _stack_ and _index_ parameters, as well as _module_'s [[DFSIndex]] and [[DFSAncestoreIndex]] fields, are used the same way as in InnerModuleInstantiation.</p>
<p>The Evaluate concrete method of a Source Text Module Record implements the corresponding Module Record abstract method.</p>
<p><ins>By the time the promise returned by Evaluate settles, </ins>Evaluate transitions this module's [[Status]] from `"instantiated"` to `"evaluated"`.</p>

<p>This abstract operation performs the following steps:</p>
<p><del>If execution results in an exception, that exception is recorded in the [[EvaluationError]] field and rethrown by future invocations of Evaluate.</del></p>

<p><ins>If execution results in a rejected promise, the promise's rejection reason is recorded in the [[EvaluationError]] field. Future invocations of Evaluate will then return a new promise rejected with that same rejection reason.</ins></p>

<p>This abstract method performs the following steps (most of the work is done by the auxiliary function InnerModuleEvaluation):</p>

<emu-alg>
1. If _module_ is not a Source Text Module Record, then
1. Perform ? _module_.Evaluate().
1. Return _index_.
1. If _module_.[[Status]] is `"evaluated"`, then
1. If _module_.[[EvaluationError]] is *undefined*, return _index_.
1. Otherwise return _module_.[[EvaluationError]].
1. If _module_.[[Status]] is `"evaluating"`, return _index_.
1. Assert: _module_.[[Status]] is `"instantiated"`.
1. Set _module_.[[Status]] to `"evaluating"`.
1. Set _module_.[[DFSIndex]] to _index_.
1. Set _module_.[[DFSAncestorIndex]] to _index_.
1. Set _index_ to _index_ + 1.
1. Append _module_ to _stack_.
1. For each String _required_ that is an element of _module_.[[RequestedModules]], do
1. Let _requiredModule_ be ! HostResolveImportedModule(_module_, _required_).
1. NOTE: Instantiate must be completed successfully prior to invoking this method, so every requested module is guaranteed to resolve successfully.
1. Set _index_ to ? InnerModuleEvaluation(_requiredModule_, _stack_, _index_).
1. Assert: _requiredModule_.[[Status]] is either `"evaluating"` or `"evaluated"`.
1. Assert: _requiredModule_.[[Status]] is `"evaluating"` if and only if _requiredModule_ is in _stack_.
1. If _requiredModule_.[[Status]] is `"evaluating"`, then
1. Assert: _requiredModule_ is a Source Text Module Record.
1. Set _module_.[[DFSAncestorIndex]] to min(_module_.[[DFSAncestorIndex]], _requiredModule_.[[DFSAncestorIndex]]).
1. Perform ? ModuleExecution(_module_).
1. Assert: _module_ occurs exactly once in _stack_.
1. Assert: _module_.[[DFSAncestorIndex]] is less than or equal to _module_.[[DFSIndex]].
1. If _module_.[[DFSAncestorIndex]] equals _module_.[[DFSIndex]], then
1. Let _done_ be *false*.
1. Repeat, while _done_ is *false*,
1. Let _requiredModule_ be the last element in _stack_.
1. Remove the last element of _stack_.
1. Set _requiredModule_.[[Status]] to `"evaluated"`.
1. If _requiredModule_ and _module_ are the same Module Record, set _done_ to *true*.
1. Return _index_.
1. Let _module_ be this Source Text Module Record.
1. Assert: _module_.[[Status]] is `"instantiated"` or `"evaluated"`.
1. <ins>Let _promiseCapability_ be ! NewPromiseCapability(%Promise%).</ins>
1. Let _stack_ be a new empty List.
1. Let _result_ be <ins>Await(</ins>InnerModuleEvaluation(_module_, _stack_, 0)<ins>)</ins>.
1. If _result_ is an abrupt completion, then
1. For each module _m_ in _stack_, do
1. Assert: _m_.[[Status]] is `"evaluating"`.
1. Set _m_.[[Status]] to `"evaluated"`.
1. Set _m_.[[EvaluationError]] to _result_.
1. Assert: _module_.[[Status]] is `"evaluated"` and _module_.[[EvaluationError]] is _result_.
1. <del>Return _result_.</del>
1. <ins>Perform ! Call(_promiseCapability_.[[Reject]], *undefined*, &laquo;_result_.[[Value]]&raquo;).</ins>
1. <ins>Return _promiseCapability_.[[Promise]].</ins>
1. Assert: _module_.[[Status]] is `"evaluated"` and _module_.[[EvaluationError]] is *undefined*.
1. Assert: _stack_ is empty.
1. <del>Return *undefined*.</del>
1. <ins>Perform ! Call(_promiseCapability_.[[Resolve]], *undefined*, &laquo;*undefined*&raquo;).</ins>
1. <ins>Return _promiseCapability_.[[Promise]].</ins>
</emu-alg>
</emu-clause>

<emu-clause id="sec-moduleexecution" aoid="ModuleExecution">
<h1>ModuleExecution( _module_ )</h1>
<emu-clause id="sec-innermoduleevaluation" aoid="InnerModuleEvaluation">
<h1>InnerModuleEvaluation( _module_, _stack_, _index_ )</h1>

<p>The ModuleExecution abstract operation is used by InnerModuleEvaluation to initialize the execution context of the module and evaluate the module's code within it.</p>
<p>The InnerModuleEvaluation abstract operation is used by Evaluate to perform the actual evaluation process for the Source Text Module Record _module_, as well as recursively on all other modules in the dependency graph. The _stack_ and _index_ parameters, as well as _module_'s [[DFSIndex]] and [[DFSAncestoreIndex]] fields, are used the same way as in InnerModuleInstantiation.</p>

<p>This abstract operation performs the following steps:</p>
<p>This abstract operation performs the following steps:</p>

<emu-alg>
1. Let _moduleCxt_ be a new ECMAScript code execution context.
1. Set the Function of _moduleCxt_ to *null*.
1. Assert: _module_.[[Realm]] is not *undefined*.
1. Set the Realm of _moduleCxt_ to _module_.[[Realm]].
1. Set the ScriptOrModule of _moduleCxt_ to _module_.
1. Assert: _module_ has been linked and declarations in its module environment have been instantiated.
1. Set the VariableEnvironment of _moduleCxt_ to _module_.[[Environment]].
1. Set the LexicalEnvironment of _moduleCxt_ to _module_.[[Environment]].
1. <ins>Let _promiseCapability_ be ! NewPromiseCapability(%Promise%).</ins>
1. Suspend the currently running execution context.
1. <ins>Perform ! AsyncBlockStart(_promiseCapability_, _module_.[[ECMAScriptCode]], _moduleCxt_).</ins>
1. <del>Push _moduleCxt_ on to the execution context stack; _moduleCxt_ is now the running execution context.</del>
1. <del>Let _result_ be the result of evaluating _module_.[[ECMAScriptCode]].</del>
1. <del>Suspend _moduleCxt_ and remove it from the execution context stack.</del>
1. Resume the context that is now on the top of the execution context stack as the running execution context.
1. Return Completion(<del>_result_</del><ins>_promiseCapability_.[[Promise]]</ins>).
</emu-alg>
</emu-clause>
<emu-alg>
1. <ins>Let _promiseCapability_ be ! NewPromiseCapability(%Promise%).</ins>
1. If _module_ is not a Source Text Module Record, then
1. <del>Perform _module_.Evaluate()</del>.
1. <del>Return _index_.</del>
1. <ins>Let _evaluateResult_ be Await(! _module_.Evaluate())</ins>
1. <ins>If _evaluateResult_ is an abrupt completion, perform ! Call(_promiseCapability_.[[Reject]], *undefined*, &laquo;_evaluateResult_.[[Value]]&raquo;).</ins>
1. <ins>Otherwise, perform ! Call(_promiseCapability_.[[Resolve]], *undefined*, &laquo;_index_&raquo;).</ins>
1. <ins>Return _promiseCapability_.[[Promise]].</ins>
1. If _module_.[[Status]] is `"evaluated"`, then
1. <del>If _module_.[[EvaluationError]] is *undefined*, return _index_.</del>
1. <del>Otherwise return _module_.[[EvaluationError]].</del>
1. <ins>If _module_.[[EvaluationError]] is an abrupt completion, perform ! Call(_promiseCapability_.[[Reject]], *undefined*, &laquo;_module_.[[EvaluationError]].[[Value]]&raquo;).</ins>
1. <ins>Otherwise, perform ! Call(_promiseCapability_.[[Resolve]], *undefined*, &laquo;_index_&raquo;).</ins>
1. <ins>Return _promiseCapability_.[[Promise]]</ins>
1. If _module_.[[Status]] is `"evaluating"`, return _index_.
1. Assert: _module_.[[Status]] is `"instantiated"`.
1. Set _module_.[[Status]] to `"evaluating"`.
1. Set _module_.[[DFSIndex]] to _index_.
1. Set _module_.[[DFSAncestorIndex]] to _index_.
1. Set _index_ to _index_ + 1.
1. Append _module_ to _stack_.
1. For each String _required_ that is an element of _module_.[[RequestedModules]], do
1. Let _requiredModule_ be ! HostResolveImportedModule(_module_, _required_).
1. NOTE: Instantiate must be completed successfully prior to invoking this method, so every requested module is guaranteed to resolve successfully.
1. <del>Set _index_ to ? InnerModuleEvaluation(_requiredModule_, _stack_, _index_).</del>
1. <ins>Let _childResult_ be Await(! InnerModuleEvaluation(_requiredModule_, _stack_, _index_).</ins>
1. <ins>IfAbruptRejectPromise(_childResult_, _promiseCapability_).
1. Assert: _requiredModule_.[[Status]] is either `"evaluating"` or `"evaluated"`.
1. Assert: _requiredModule_.[[Status]] is `"evaluating"` if and only if _requiredModule_ is in _stack_.
1. If _requiredModule_.[[Status]] is `"evaluating"`, then
1. Assert: _requiredModule_ is a Source Text Module Record.
1. Set _module_.[[DFSAncestorIndex]] to min(_module_.[[DFSAncestorIndex]], _requiredModule_.[[DFSAncestorIndex]]).
1. <del>Perform ? ModuleExecution(_module_).</del>
1. <ins>Let _executionResult_ be Await(! ModuleExecution(_module_)).</ins>
1. <ins>IfAbruptRejectPromise(_executionResult_, _promiseCapability_).
1. Assert: _module_ occurs exactly once in _stack_.
1. Assert: _module_.[[DFSAncestorIndex]] is less than or equal to _module_.[[DFSIndex]].
1. If _module_.[[DFSAncestorIndex]] equals _module_.[[DFSIndex]], then
1. Let _done_ be *false*.
1. Repeat, while _done_ is *false*,
1. Let _requiredModule_ be the last element in _stack_.
1. Remove the last element of _stack_.
1. Set _requiredModule_.[[Status]] to `"evaluated"`.
1. If _requiredModule_ and _module_ are the same Module Record, set _done_ to *true*.
1. <del>Return _index_.</del>
1. <ins>Perform ! Call(_promiseCapability_.[[Resolve]], *undefined*, &laquo;_index_&raquo;).</ins>
1. <ins>Return _promiseCapability_.[[Promise]]</ins>
</emu-alg>
</emu-clause>

<emu-clause id="sec-moduleexecution" aoid="ModuleExecution">
<h1>ModuleExecution( _module_ )</h1>

<p>The ModuleExecution abstract operation is used by InnerModuleEvaluation to initialize the execution context of the module and evaluate the module's code within it.</p>

<p>This abstract operation performs the following steps:</p>

<emu-alg>
1. Let _moduleCxt_ be a new ECMAScript code execution context.
1. Set the Function of _moduleCxt_ to *null*.
1. Assert: _module_.[[Realm]] is not *undefined*.
1. Set the Realm of _moduleCxt_ to _module_.[[Realm]].
1. Set the ScriptOrModule of _moduleCxt_ to _module_.
1. Assert: _module_ has been linked and declarations in its module environment have been instantiated.
1. Set the VariableEnvironment of _moduleCxt_ to _module_.[[Environment]].
1. Set the LexicalEnvironment of _moduleCxt_ to _module_.[[Environment]].
1. <ins>Let _promiseCapability_ be ! NewPromiseCapability(%Promise%).</ins>
1. Suspend the currently running execution context.
1. <ins>Perform ! AsyncBlockStart(_promiseCapability_, _module_.[[ECMAScriptCode]], _moduleCxt_).</ins>
1. <del>Push _moduleCxt_ on to the execution context stack; _moduleCxt_ is now the running execution context.</del>
1. <del>Let _result_ be the result of evaluating _module_.[[ECMAScriptCode]].</del>
1. <del>Suspend _moduleCxt_ and remove it from the execution context stack.</del>
1. Resume the context that is now on the top of the execution context stack as the running execution context.
1. <del>Return Completion(_result_).</del>
1. <ins>Return _promiseCapability_.[[Promise]].</ins>
</emu-alg>
</emu-clause>
</emu-clause>

<emu-clause id="sec-async-functions-abstract-operations-async-function-start" aoid="AsyncFunctionStart">
<h1>AsyncFunctionStart ( _promiseCapability_, _asyncFunctionBody_ )</h1>
Expand Down