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#4042 — B.1.4: overdone grammatical parameters

• bug_id: 4042
• creation_ts: 2015-02-20 13:36:00 -0800
• short_desc: B.1.4: overdone grammatical parameters
• delta_ts: 2015-02-24 12:00:15 -0800
• product: Draft for 6th Edition
• component: editorial issue
• version: Rev 34: February 20, 2015 Release Candidate 1
• rep_platform: All
• op_sys: All
• bug_status: RESOLVED
• resolution: INVALID
• priority: Normal
• bug_severity: normal
• everconfirmed: true
• reporter: Michael Dyck
• assigned_to: Allen Wirfs-Brock

---

• commentid: 13213
• comment_count: 0
• who: Michael Dyck
• bug_when: 2015-02-20 13:36:46 -0800

In B.1.4 "Regular Expressions Patterns",
under "Syntax",
the last production is:
ClassEscape[U] ::
[+U] DecimalEscape
[+U] CharacterEscape[U]
[+U] CharacterClassEscape
[~U] DecimalEscape
b
[~U] CharacterClassEscape
[~U] CharacterEscape

It seems like there's no reason to have
[+U] DecimalEscape
and
[~U] DecimalEscape
Replace with just:
DecimalEscape

Similarly for:
[+U] CharacterClassEscape
[~U] CharacterClassEscape

Moreover, the pair
[+U] CharacterEscape[U]
[~U] CharacterEscape
is presumably equivalent to just
CharacterEscape[?U]


Leaving just:
ClassEscape[U] ::
DecimalEscape
b
CharacterEscape[?U]
CharacterClassEscape

(i.e., same as the production in 21.2.1, except for the "[+U]-" rhs.)

---

• commentid: 13290
• comment_count: 1
• who: Allen Wirfs-Brock
• bug_when: 2015-02-24 11:31:03 -0800

the grammar in B.1.4 uses the ordering of productions for disambiguation (see the first paragraph of B.1.4)

The occurrences on [+U] and [~U] prefixes gives the corresponding RHS rules different disambiguation priorities.

---

• commentid: 13292
• comment_count: 2
• who: Michael Dyck
• bug_when: 2015-02-24 12:00:15 -0800

Ah, right.
Resolved invalid then.