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digitalmars.D.bugs - [Issue 2804] New: Impure nested functions should be legal inside pure functions[patch included]

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2804

           Summary: Impure nested functions should be legal inside pure
                    functions[patch included]
           Product: D
           Version: 2.027
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Keywords: patch, rejects-valid
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: clugdbug yahoo.com.au


Example contributed by bearophile.

------
import std.c.stdio: printf;
import std.conv: toInt;

pure int double_sqr(int x) {
    int y, z;
    void do_sqr() { y *= y; }
    y = x;
    do_sqr();
    z += y;
    y = x;
    do_sqr();
    z += y;
    return z;
}

void main(string[] args) {
    int x = args.length == 2 ? toInt(args[1]) : 10;
    int y = double_sqr(x) + double_sqr(x);
    printf("4 * x * x = %d\n", y);
}
--------
pure_test3.d(...): Error: pure function 'double_sqr' cannot call impure
function 'do_sqr'

pure_test3.d(...): Error: pure function 'double_sqr' cannot call impure
function 'do_sqr'


-- 
Apr 06 2009
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2804





------- Comment #1 from clugdbug yahoo.com.au  2009-04-06 06:30 -------
Created an attachment (id=315)
 --> (http://d.puremagic.com/issues/attachment.cgi?id=315&action=view)
patch for 2804

This allows pure functions to call their own nested functions (even if such
functions aren't marked as pure), but prevents nested functions inside pure
functions from 
(1) calling impure functions and
(2) accessing static variables.


-- 
Apr 06 2009
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2804


clugdbug yahoo.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED




------- Comment #2 from clugdbug yahoo.com.au  2009-04-18 01:05 -------
Fixed DMD2.028


-- 
Apr 17 2009