Skip to Content.
Sympa Menu

sm-sorcery-bugs - [SM-Sorcery-Bugs] [Bug 10747] 'gaze dependencies' to display conditional deps

sm-sorcery-bugs AT lists.ibiblio.org

Subject: Bugs for Sorcery are reported here

List archive

Chronological Thread  
  • From: bugzilla-daemon AT bugs.sourcemage.org
  • To: sm-sorcery-bugs AT lists.ibiblio.org
  • Subject: [SM-Sorcery-Bugs] [Bug 10747] 'gaze dependencies' to display conditional deps
  • Date: 22 Mar 2006 20:39:16 -0000

http://bugs.sourcemage.org/show_bug.cgi?id=10747





------- Additional Comments From acedit AT armory.com 2006-03-22 14:39 -------
It is *very* hard to do. Its provably impossible within current known
computational models.

Say theres a routine halt_check that is given a function and determines if it
halts or not. Say we think we've solved the halting problem and codified it.
If
the functions halts halt_check returns 'TRUE', if not 'FALSE'. Heres a simple
proof of how halt_check cannot work in general.

foo() { while (halt_check(foo) == TRUE); }

Two outcomes:
halt_check says 'TRUE' foo does in fact halt. The loop in foo runs forever, so
foo actually doesnt halt.

halt_check says 'FALSE' foo does not halt. The loop condition is false and foo
halts.

Foo is written to do the opposite of whatever halt_check says. So halt_check
is
wrong and cannot work in general.

The existing implementation is really more of a hack than anything imho. Its
based on the idea that people dont usually do any real scripting in DEPENDS,
which of course isnt true. So it gets 90% of the way there, the remaining 10%
of
functionalizing the conditionals and having them understand the difference
between normal execution and gaze dependencies execution is a whole lot more
work. And of course, its a loosing strategy because if someone ever goes
outside
of that, things break again (like now).


--
Configure bugmail: http://bugs.sourcemage.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.




Archive powered by MHonArc 2.6.24.

Top of Page