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Introduce a shorthand for ECMA262 abstract ops #539

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Introduce a shorthand for ECMA262 abstract ops #539

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6c12fea
Introduce a shorthand for ECMA262 abstract ops
jugglinmike Jan 24, 2023
9b86216
fixup! Introduce a shorthand for ECMA262 abstract ops
jugglinmike Feb 17, 2023
da1baac
fixup! Introduce a shorthand for ECMA262 abstract ops
jugglinmike Feb 23, 2023
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49 changes: 46 additions & 3 deletions infra.bs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,8 +14,11 @@ urlPrefix: https://tc39.github.io/ecma262/#; spec: ECMA-262;
type: dfn
text: %JSON.parse%; url: sec-json.parse
text: %JSON.stringify%; url: sec-json.stringify
text: Completion Record; url: sec-completion-record-specification-type
text: List; url: sec-list-and-record-specification-type
text: The String Type; url: sec-ecmascript-language-types-string-type
text: abrupt completion; url: sec-completion-record-specification-type
text: abstract operation; url: sec-algorithm-conventions-abstract-operations
text: realm; url: realm
type: method; for: Array; text: sort(); url: sec-array.prototype.sort
type: abstract-op;
Expand Down Expand Up @@ -644,6 +647,46 @@ Standard that should be reported and addressed.
</div>


<h3 id=ecma-262-abstract-operations>ECMA-262 Abstract Operations</h3>

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<p>ECMA-262 defines some algorithms as [=abstract operations=] which may be invoked from algorithms
in other specifications. Some of these [=abstract operations=] return a type of value named
[=Completion Record=] which ECMA262 uses to model control flow interruptions such as thrown
exceptions. Because web specifications do not observe the same conventions (e.g.
<a href=#algorithm-control-flow>exception handling is built in to the processing model</a>),
preserving the operations' semantics necessarily involves handling [=Completion Records=].
[[!ECMA-262]]

<p>This specification defines a shorthand named <dfn export lt=throw-if-abrupt>?</dfn> as a
convenience for web specifications wishing to faithfully interpret ECMA-262 [=abstract operations=]
which return [=Completion Records=]. Algorithms which invoke such operations are encouraged to
integrate them concisely and consistently using this shorthand.

<p>Algorithm steps that say or are otherwise equivalent to:

<div class=example id=example-throw-if-abrupt>
<ol>
<li><p>Let |result| be <a lt=throw-if-abrupt>?</a> AbstractOperation().
</ol>
</div>

<p>mean the same thing as:

<div class=example id=example-throw-if-abrupt-expanded>
<ol>
<li><p>Let |hygienicTemp| be AbstractOperation().
<li><p><a>Assert</a>: |hygienicTemp| is a [=Completion Record=].
<li><p>If |hygienicTemp| is an [=abrupt completion=], throw |hygienicTemp|.\[[Value]].
<li><p>Let |result| be |hygienicTemp|.\[[Value]].
</ol>
</div>


<p class=XXX>This shorthand is intended to be suitable for use with any invocation, but the first
of the two preceding examples does not match all common calling conventions. See <a href=https://github.com/tc39/ecma262/pull/1573>tc39/ecma262 issue #1573</a>
for details.


<h2 id=primitive-data-types>Primitive data types</h2>

<h3 id=nulls>Nulls</h3>
Expand Down Expand Up @@ -1727,7 +1770,7 @@ specification. [[!ECMA-262]]
given a <a>string</a> |string|:

<ol>
<li><p>Return ? [$Call$](<a>%JSON.parse%</a>, undefined, « |string| »).
<li><p>Return <a lt=throw-if-abrupt>?</a> [$Call$](<a>%JSON.parse%</a>, undefined, « |string| »).
</ol>

<p>To <dfn export lt="parse JSON bytes to a JavaScript value|parsing JSON bytes to a JavaScript value|parse JSON from bytes">parse JSON bytes to a JavaScript value</dfn>,
Expand All @@ -1744,7 +1787,7 @@ given a JavaScript value |value|:

<ol>
<li>
<p>Let |result| be ? [$Call$](<a>%JSON.stringify%</a>, undefined, « |value| »).
<p>Let |result| be <a lt=throw-if-abrupt>?</a> [$Call$](<a>%JSON.stringify%</a>, undefined, « |value| »).

<p class=note>Since no additional arguments are passed to <a>%JSON.stringify%</a>, the resulting
string will have no whitespace inserted.
Expand Down Expand Up @@ -1781,7 +1824,7 @@ standards, it is often more convenient to convert between JSON and realm-indepen
given a <a>string</a> |string|:

<ol>
<li><p>Let |jsValue| be ? [$Call$](<a>%JSON.parse%</a>, undefined, « |string| »).
<li><p>Let |jsValue| be <a lt=throw-if-abrupt>?</a> [$Call$](<a>%JSON.parse%</a>, undefined, « |string| »).

<li><p>Return the result of [=converting a JSON-derived JavaScript value to an Infra value=], given
|jsValue|.
Expand Down