archives

« Bugzilla Issues Index

#2440 — 12.1.4.2.5 Evaluation: Missing runtime evaluation semantics for "Comprehension" production

• bug_id: 2440
• creation_ts: 2014-01-27 06:37:00 -0800
• short_desc: 12.1.4.2.5 Evaluation: Missing runtime evaluation semantics for "Comprehension" production
• delta_ts: 2014-04-06 11:30:17 -0700
• product: Draft for 6th Edition
• component: technical issue
• version: Rev 22: January 20, 2014 Draft
• rep_platform: All
• op_sys: All
• bug_status: RESOLVED
• resolution: FIXED
• priority: Normal
• bug_severity: normal
• everconfirmed: true
• reporter: André Bargull
• assigned_to: Allen Wirfs-Brock

---

• commentid: 7009
• comment_count: 0
• who: André Bargull
• bug_when: 2014-01-27 06:37:20 -0800

12.1.4.2.5 Runtime Semantics: Evaluation.

The evaluation semantics for "Comprehension" are missing, these are required for evaluating generator comprehensions.

See:
- 14.4.11 Runtime Semantics: EvaluateBody "GeneratorBody : Comprehension"
- 25.3.3.1 GeneratorStart (generator, generatorBody), step 4a

Step 4a of GeneratorStart cannot be executed without a corresponding "Runtime Semantics: Evaluation" for Comprehension.


The concrete steps should look like:
---
1. Let status be the result of performing ComprehensionEvaluation for Comprehension with argument `undefined`.
2. ReturnIfAbrupt(status).
3. Return NormalCompletion(undefined).
---

---

• commentid: 7127
• comment_count: 1
• who: Allen Wirfs-Brock
• bug_when: 2014-01-27 11:09:57 -0800

Fixed in rev23 editor's draft.

Note that steps 2 and 3 of the suggested fix are unnecessary because ComprehensionComponentEvaluation for ComprehensionFor takes care of producing the normal completion of undefined. The version I put in the spec just returns the ComprehensionEvaluation result.

---

• commentid: 7552
• comment_count: 2
• who: Allen Wirfs-Brock
• bug_when: 2014-04-06 11:30:17 -0700

fixed in rev23 draft