To:         J3                                       J3/14-191
From:       Van Snyder
Subject:    Delete <do-block> and Range of the DO construct
Date: 2014 June 16
References: 14-007r1, 14-166

1. Introduction
===============

In 14-166, Malcolm recommended to delete the <do-block> syntax term and
the "Range of the DO construct" subclause.  We can't delete the "Range
of the DO construct" subclause without replacing references to "the
range of the loop" with "the <block> of the loop" in several places, and
prohibiting branching to the <end-do-stmt> from outwith the construct.

2. Edits to 14-007r1
====================

[174:14 R813] Replace "<do-block>" with "<block>".

[175:5 R823] Delete the <do-block> syntax rule.

IF ( neither section 3 nor section 4 below is done ) THEN

  [175:15-17 8.1.6.3p1] Replace the paragraph:

  "The range of a DO construct is its <block>."  It is permitted to branch
  to the <end-do> of a DO construct only from within that DO construct."

END IF

[176:3 8.1.6.5.1p2] Replace "<do-block>" with "<block> of the
<do-construct>".

3. Replacing "range"
====================

[174:9 8.1.6.1p3] Replace "<range>" with "<block>".

IF ( section 4 below is not done ) THEN

  [175:15-17 8.1.6.3p1] Replace the paragraph:

  "It is permitted to branch to the <end-do> of a DO construct only from
  within that DO construct."

END IF

[176:34 8.1.6.5.3p1(2)] Replace "<range>" with "<block>".

[177:5-6 8.1.6.5.3p3] Replace "range" with "<block>" twice.

[177:8 8.1.6.5.4p1] Replace "<range>" with "<block>".

[177:8-9 8.1.6.5.4p1] Replace "<range> of the loop" with "<block> of the
construct".

[177:11-12 C822] Replace "range" with "<block>" twice.

[177:29,32,33 8.1.6.5.5p1] Replace "range" with "<block>" thrice.

[178:23+5 Note 8.11] Replace "range" with "<block>".

[179:0+12 Note 8.14] Replace "range" with "<block>".

[179:0+25 Note 8.15] Replace "range" with "<block>".

[186:5 C846] Replace "range" with "<block>".

4. Constraining against branching to <end-...-stmt> from
   outwith its construct
========================================================

Subclause 8.1.6.3 "Range of the DO construct" prohibits branching to an
<end-do> statement from outwith the construct, but it's not a
constraint.

Prohibitions against branching to an <end-associate-stmt>,
<end-if-stmt>, <end-select-stmt>, or <end-select-type-stmt> are not
constraints, and are not in the subclause on branching.  There is no
prohibition against branching to an <end-block-stmt> or
<end-critical-stmt> from outwith its construct (nor is there explicit
permission for it, as there once was for END IF).

[25:10+ 1.6.3p1+] Within the list of incompatibilities with Fortran
2008, add a list item:

" o Fortran 2008 did not prohibit branching to an <end-block-stmt> or
    <end-critical-stmt> from outwith its construct.  \Thisstandard
    prohibits branching thereto." {forsooth}

[187:12+ 8.2.1p1+] Insert a constraint:

"C847a If a branch target statement is an <end-associate-stmt>,
       <end-block-stmt>, <end-critical-stmt>, <end-do-stmt>,
       <end-if-stmt>, <end-select-stmt>, or <end-select-type-stmt>, the
       branching statement that references the label of that branch
       target statement shall be within the construct completed by that
       branch target statement."

[170:35 8.1.3.2p3] Delete the paragraph.

IF ( Section 3 above is done ) THEN

  [175:14-17 8.1.6.3] Delete the "Range of the DO construct" subclause
  because the term "range" is no longer needed, and the rest of it
  doesn't say anything not already said in subclause 8.1.2 and by the
  new constraint C847a.

ELSE

  [175:15-17 8.1.6.3p1] Replace the paragraph:

  "The range of a DO construct is its <block>."

END IF

[180:29-30 8.1.7.1p2] Delete the paragraph.

[182:33 8.1.8.2p3] Delete the paragraph.

[185:33 8.1.9.2p9] Delete the paragraph.