• Walter Bright (2/2) Oct 29 2015 https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/
• Walter Bright (3/5) Oct 29 2015 Reddit:
• rsw0x (2/4) Oct 29 2015 how does this differ from static if and version(x) hell?
• Walter Bright (3/8) Oct 29 2015 We advise people not to use static if to do what version(x) eschews, and...
• David Nadlinger (6/16) Oct 29 2015 Ha, I wish!
• Jonathan M Davis (12/20) Oct 29 2015 The idea is that you get rid of all of the &&ing and ||ing that
• Joakim (262/271) Nov 02 2015 I agree that his position is consistent, but I disagree that it
• Walter Bright (7/9) Oct 29 2015 I presented several ways to avoid using complex version statements.
• Jacob Carlborg (5/9) Oct 30 2015 The DMD source code contained #ifdef's inside expressions, which is
• Daniel Murphy (4/11) Nov 02 2015 Yes, this was the major problem with converting the #ifdefs, not
• anonymous (4/14) Oct 30 2015 The same thing can be said about #ifdef. Conventional wisdom in

Walter Bright <newshound2 digitalmars.com> writes:

https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/

Another voice on what is wrong with the snarl of #ifdef's.

Walter Bright <newshound2 digitalmars.com> writes:

On 10/29/2015 3:18 PM, Walter Bright wrote:
 https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/

 Another voice on what is wrong with the snarl of #ifdef's.

Reddit: 
https://www.reddit.com/r/programming/comments/3qo79b/living_in_the_ifdef_hell/

rsw0x <anonymous anonymous.com> writes:

On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright wrote:
 https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/

 Another voice on what is wrong with the snarl of #ifdef's.

how does this differ from static if and version(x) hell?

Walter Bright <newshound2 digitalmars.com> writes:

On 10/29/2015 3:23 PM, rsw0x wrote:
 On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright wrote:
 https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/

 Another voice on what is wrong with the snarl of #ifdef's.

 how does this differ from static if and version(x) hell?

We advise people not to use static if to do what version(x) eschews, and
suggest 
better alternatives.

David Nadlinger <code klickverbot.at> writes:

On Thursday, 29 October 2015 at 23:10:38 UTC, Walter Bright wrote:
 On 10/29/2015 3:23 PM, rsw0x wrote:
 On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright 
 wrote:
 https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/

 Another voice on what is wrong with the snarl of #ifdef's.

 how does this differ from static if and version(x) hell?

 We advise people not to use static if to do what version(x) 
 eschews, and suggest better alternatives.

Ha, I wish!

In fact, you are currently arguing for people to write *more* 
version statements over at the 
https://github.com/D-Programming-Language/dmd/pull/5231

  — David

Jonathan M Davis <jmdavisProg gmx.com> writes:

On Thursday, 29 October 2015 at 23:14:26 UTC, David Nadlinger 
wrote:
 On Thursday, 29 October 2015 at 23:10:38 UTC, Walter Bright 
 wrote:
 We advise people not to use static if to do what version(x) 
 eschews, and suggest better alternatives.

 Ha, I wish!

 In fact, you are currently arguing for people to write *more* 
 version statements over at the 
 https://github.com/D-Programming-Language/dmd/pull/5231

The idea is that you get rid of all of the &&ing and ||ing that 
tends to make #ifdefs really hard to follow and error-prone. And 
by having each version fully separate, changing one version won't 
break another.

Now, that comes at the cost of forcing you to duplicate a lot of 
code, which almost everyone other than Walter thinks is worse 
than the risks associated with merging similar versions together, 
but as far as I can tell, Walter is completely consistent in his 
arguments.

- Jonathan M Davis

Joakim <dlang joakim.fea.st> writes:

On Thursday, 29 October 2015 at 23:55:14 UTC, Jonathan M Davis 
wrote:
 The idea is that you get rid of all of the &&ing and ||ing that 
 tends to make #ifdefs really hard to follow and error-prone. 
 And by having each version fully separate, changing one version 
 won't break another.

 Now, that comes at the cost of forcing you to duplicate a lot 
 of code, which almost everyone other than Walter thinks is 
 worse than the risks associated with merging similar versions 
 together, but as far as I can tell, Walter is completely 
 consistent in his arguments.

I agree that his position is consistent, but I disagree that it 
implies duplicating all your code.  He suggests one possibility 
in that thread where you can keep code common to OS X and iOS in 
a single version(Darwin) block, but explicitly stick a 
"version(OSX) version = Darwin; version(iOS) version = Darwin;" 
at the top of each druntime file that does so.  While that may 
look like a pimple at the top of each file, it has the virtue 
that it explicitly, locally documents exactly where this new 
version is coming from.

Note that that's only for druntime and phobos: users are always 
free to define Darwin for themselves in their build scripts if 
they want.

The alternative in current compilers like gcc is this mess, as he 
notes on that PR:


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#define __SIZEOF_PTRDIFF_T__ 4
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#define __pentiumpro 1
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#define __FLT_DIG__ 6
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#define __DBL_MANT_DIG__ 53
#define __SIZEOF_FLOAT128__ 16
#define __INT_LEAST64_MAX__ 0x7fffffffffffffffLL
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __DEC64_MIN__ 1E-383DD
#define __WINT_TYPE__ unsigned int
#define __UINT_LEAST32_TYPE__ unsigned int
#define __SIZEOF_SHORT__ 2
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#define __INT_LEAST8_MAX__ 0x7f
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#define __ATOMIC_RELAXED 0
#define __DBL_EPSILON__ ((double)2.22044604925031308085e-16L)
#define __UINT8_C(c) c
#define __INT_LEAST32_TYPE__ int
#define __SIZEOF_WCHAR_T__ 4
#define __UINT64_TYPE__ long long unsigned int
#define __INT_FAST8_TYPE__ signed char
#define __GNUC_STDC_INLINE__ 1
#define __DBL_DECIMAL_DIG__ 17
#define __STDC_UTF_32__ 1
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#define __ORDER_BIG_ENDIAN__ 4321
#define
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#define __FLT_DENORM_MIN__ 1.40129846432481707092e-45F
#define __INT8_MAX__ 0x7f
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#define __CHAR32_TYPE__ unsigned int
#define __FLT_MAX__ 3.40282346638528859812e+38F
#define __INT32_TYPE__ int
#define __SIZEOF_DOUBLE__ 8
#define __FLT_MIN_10_EXP__ (-37)
#define __INTMAX_TYPE__ long long int
#define i386 1
#define __DEC128_MAX_EXP__ 6145
#define __ATOMIC_CONSUME 1
#define __GNUC_MINOR__ 2
#define __UINTMAX_MAX__ 0xffffffffffffffffULL
#define __DEC32_MANT_DIG__ 7
#define __DBL_MAX_10_EXP__ 308
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
#define __INT16_C(c) c
#define __STDC__ 1
#define __PTRDIFF_TYPE__ int
#define __ATOMIC_SEQ_CST 5
#define __UINT32_TYPE__ unsigned int
#define __UINTPTR_TYPE__ unsigned int
#define __DEC64_SUBNORMAL_MIN__ 0.000000000000001E-383DD
#define __DEC128_MANT_DIG__ 34
#define __LDBL_MIN_10_EXP__ (-4931)
#define __SIZEOF_LONG_LONG__ 8
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __LDBL_DIG__ 18
#define __FLT_DECIMAL_DIG__ 9
#define __UINT_FAST16_MAX__ 0xffffffffU
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __UINT_FAST8_TYPE__ unsigned char
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3

Note the __linux__, __linux, linux, and __gnu_linux__. :) Of 
course, that extreme doesn't imply adding a couple more 
predefined versions to D would automatically land us there, but I 
can see why he doesn't want to start going down that slippery 
slope.

Walter Bright <newshound2 digitalmars.com> writes:

On 10/29/2015 4:14 PM, David Nadlinger wrote:
 In fact, you are currently arguing for people to write *more* version
statements
 over at the https://github.com/D-Programming-Language/dmd/pull/5231

I presented several ways to avoid using complex version statements.

I might add that over time, I'd been removing #if's and #ifdef's from the dmd 
front end source code. The results were very satisfactory - the code was easier 
to read, understand and maintain. It also made running magicport on the code 
practical.

I've been slowly doing the same to the back end.

Jacob Carlborg <doob me.com> writes:

On 2015-10-30 03:01, Walter Bright wrote:

 I might add that over time, I'd been removing #if's and #ifdef's from
 the dmd front end source code. The results were very satisfactory - the
 code was easier to read, understand and maintain. It also made running
 magicport on the code practical.

The DMD source code contained #ifdef's inside expressions, which is 
quite a difference compared to "or" and "and" in "static if".

-- 
/Jacob Carlborg

Daniel Murphy <yebbliesnospam gmail.com> writes:

On 31/10/2015 12:01 AM, Jacob Carlborg wrote:
 On 2015-10-30 03:01, Walter Bright wrote:

 I might add that over time, I'd been removing #if's and #ifdef's from
 the dmd front end source code. The results were very satisfactory - the
 code was easier to read, understand and maintain. It also made running
 magicport on the code practical.

 The DMD source code contained #ifdef's inside expressions, which is
 quite a difference compared to "or" and "and" in "static if".

Yes, this was the major problem with converting the #ifdefs, not 
conditions ||ed together.  If D allowed oring versions together then 
version would have been a lot more useful in DDMD.

anonymous <anonymous anonymous.com> writes:

On Thursday, 29 October 2015 at 23:10:38 UTC, Walter Bright wrote:
 On 10/29/2015 3:23 PM, rsw0x wrote:
 On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright 
 wrote:
 https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/

 Another voice on what is wrong with the snarl of #ifdef's.

 how does this differ from static if and version(x) hell?

 We advise people not to use static if to do what version(x) 
 eschews, and suggest better alternatives.

The same thing can be said about #ifdef. Conventional wisdom in 
C++ says there's better ways, but the abuse compiles thus 
continually abused.