J3/06-143

Date:       16 February 2006
To:         J3
From:       Van Snyder
Subject:    Edits for impure elementals
Number:     UK-011
References: N1649, J3/05-238

Detailed Specification:

Introduce a new keyword, IMPURE, which is the opposite of PURE.

An ELEMENTAL procedure remains PURE by default but may be declared
IMPURE.  Such a procedure must still satisfy the "elemental"
requirements but need not satisfy the "pure" requirements.

As before, a non-ELEMENTAL procedure is IMPURE by default but may be
declared PURE.  For consistency, since an ELEMENTAL procedure may
redundantly be declared PURE, allow a non-ELEMENTAL procedure to be
redundantly declared IMPURE.

Edits to J3/04-007:

[18:16-17] In the final two lines of the third paragraph of 2.4.5,
delete ", and all such element operations may be performed in any
order or simultaneously".

Insert a Note after the paragraph:

NOTE 2.4a
If an elemental operation is intrinsically pure or is implemented by a
pure elemental function (12.7), the element operations may be performed
simultaneously or in any order.

[129:2] In the line before NOTE 7.13, delete "The processor may
perform the element-by-element operations in any order."

[129:4] In the sentence after NOTE 7.13, delete ", in any order,".

Insert a note after the paragraph:

NOTE 7.13a
If an elemental operation is intrinsically pure or is implemented by a
pure elemental function (12.7), the element operations may be performed
simultaneously or in any order.

[142:28] In the first sentence of the second paragraph of 7.4.1.5,
delete ", in any order,".

[143:1-] At the end of Note 7.42, add a sentence: "If elemental assignment
is defined by a pure elemental subroutine, the element assignments may be
performed simultaneously or in any order."

[280:2+] Add to R1228, after "<<or>> PURE":
          <<or>> IMPURE

[280:5+] Add constraint on R1227:
    C1241a (R1227) A prefix shall not specify both PURE and IMPURE.

[281:1] In the line after NOTE 12.37, after "ELEMENTAL appears" add
"and IMPURE does not appear".

[281:3-4, 282:28-29] Replace the paragraph before NOTE 12.37 and the last
paragraph of 12.5.2.2 by

 "If the <prefix-spec> ELEMENTAL appears, the subprogram is an
 elemental subprogram. If the <prefix-spec> ELEMENTAL appears and
 IMPURE does not appear, the subprogram is a pure elemental
 subprogram and shall meet the additional constraints of 12.7.1."

[282:26] In the penultimate paragraph of 12.5.2.2, after "ELEMENTAL
appears" add "and IMPURE does not appear".

[284:18,19] In the penultimate paragraph of 12.5.2.4, replace "keyword
PURE is" by "keywords PURE and IMPURE are".  After "ELEMENTAL is
specified" add "and IMPURE is not specified".

[286:9] In the second paragraph of 12.6, after "ELEMENTAL" add
"and does not have the <prefix-spec> IMPURE".

[287:13] In the second paragraph of 12.7.1, replace the second line by
"program unless it has the <prefix-spec> IMPURE. The".

[287:14] In the final line of the second paragraph of 12.7.1, before
"elemental" add "pure".

[287:15] In C1277 change "an elemental" to "a pure elemental".

[287:17] In C1278 change "an elemental" to "a pure elemental".

[288:2] In C1279 change "an elemental" to "a pure elemental".

[288:11] In the line before NOTE 12.48, replace "in any order" by "in
array element order".

[289:8-9] In the last two lines of the first paragraph of 12.7.3,
replace "in any order" by "in array element order".