Only that it requires setting up infrastructure simply to get a
reliable answer to a question about Ruby’s environment. I expect such
in other languages; in Ruby it seems really out of place (to me).
Thanks for your code snippet.
On 2004 Apr 30, at 10:24, Ara.T.Howard wrote:
what’s wrong with solving it by planning for it?
–
Ryan “John” Platte
Custom services, NIKA Consulting
http://nikaconsulting.com/
Agree, the line ‘if FILE == $0’ is indeed ugly
There is 4 things wrong with it:
A) $0 is a global variable, with a very short name,
not selfexplaining.
B) people sometimes write to $0, when they want to tell
ps or top, what the process are currently doing.
this is fragile, I have been hit by it one time.
C) FILE and $0 is relative paths.
this is fragile, I have been hit by it more than one time.
D) making the comparison, seems kludgy.
I remember it took me forever to figure these things out.
I think its time to rethink FILE and get rid of $0.
“Robert Klemme” bob.news@gmx.net wrote:
“Kent Dahl” kentda+news@stud.ntnu.no schrieb im Newsbeitrag
news:c6tmj9$58n$1@orkan.itea.ntnu.no…Robert Klemme wrote:
Where would you expect it to reside? Maybe the best solution is
$0 : path as used for invocation
FILE: abs path to current fileThen I agree.
Any objections? Does this break existing code?
Wouldn’t this break the idiom of using
if FILE == $0 then
#…
endto make a file both require-able and executable?
I know I use it frequently.Yeah, I think it is used quite frequently. Darn. The only ad hoc
sulution to this that occurs to me is to override FILE#== and $0#== to
repair this. Now this starts getting ugly… Simon?
–
Simon Strandgaard
I don’t intend to be non-friendly, but if you do so in all your Main classes,
then it looks like kludge to me. You wouldn’t have to make such work-arounds
if FILE were with an absolute path.
I don’t know if all this rethinking FILE/$0 makes sense…
“Ara.T.Howard” ahoward@fattire.ngdc.noaa.gov wrote:
it seems we can’t determine the absolute path of FILE correctly
after a chdir without having planned for that eventuality before the
chdir.Can someone solve that one?
what’s wrong with this, i do it in all my programs:
require ‘pathname’
class Main
…
FILE = Pathname.new(FILE).realpath.to_s
…
endwhat’s wrong with solving it by planning for it?
–
Simon Strandgaard
“Simon Strandgaard” neoneye@adslhome.dk schrieb im Newsbeitrag
news:20040430175242.7aa717ad.neoneye@adslhome.dk…
“Kent Dahl” kentda+news@stud.ntnu.no schrieb im Newsbeitrag
news:c6tmj9$58n$1@orkan.itea.ntnu.no…Robert Klemme wrote:
Where would you expect it to reside? Maybe the best solution is
$0 : path as used for invocation
FILE: abs path to current fileThen I agree.
Wouldn’t this break the idiom of using
if FILE == $0 then
#…
endto make a file both require-able and executable?
I know I use it frequently.Yeah, I think it is used quite frequently. Darn. The only ad hoc
sulution to this that occurs to me is to override FILE#== and
$0#== to
repair this. Now this starts getting ugly… Simon?Agree, the line ‘if FILE == $0’ is indeed ugly
There is 4 things wrong with it:
A) $0 is a global variable, with a very short name,
not selfexplaining.
… but known from the earlies shell scripts.
B) people sometimes write to $0, when they want to tell
ps or top, what the process are currently doing.
this is fragile, I have been hit by it one time.
Yep.
C) FILE and $0 is relative paths.
this is fragile, I have been hit by it more than one time.
They are not always relative, it depends on the invocation.
D) making the comparison, seems kludgy.
Well, sort of.
I remember it took me forever to figure these things out.
I think its time to rethink FILE and get rid of $0.
I certainly disagree here: $0 never changes automatically during the
lifetime of a script while FILE reflects the current file. That’s an
important distinction in the light of require and load. Just imagine a
help module that automatically prints invocation hints…
Regards
robert
“Robert Klemme” bob.news@gmx.net wrote:
it seems we can’t determine the absolute path of FILE correctly
after a chdir without having planned for that eventuality before the
chdir.Can someone solve that one?
what’s wrong with this, i do it in all my programs:
require ‘pathname’
class Main
…
FILE = Pathname.new(FILE).realpath.to_s
…
endwhat’s wrong with solving it by planning for it?
I don’t intend to be non-friendly, but if you do so in all your Main
classes, then it looks like kludge to me. You wouldn’t have to make such
work-arounds if FILE were with an absolute path.
i have to disagree - the reason i do it is that i drive alot of external
programs which dump their output in the cwd, therefore i end up doing a lot of
Dir.chdir’s (see my dirstack package on RAA)… i have several main templates
and a code generator which uses these templates to spit out a main program of
several common flavors. one of things i find useful is knowing the absolute
path of the invoked program file because i’m planning on doing a lot of
chdirs… some of my other templates do not include this. by your logic my
option parsing would be a kludge since it always has a ‘–help’ and ‘–log’
option and there should be a way to avoid such duplicate effort… then again
perhaps you are correct, witness perl’s pod2usage. code generators are a nice
way to get somewhere fast though…
I don’t know if all this rethinking FILE/$0 makes sense…
i think it makes perfect sense to have
FILE => absolute path of script file
PROGRAM => absolute path of called program
RUBY => absolute path of ruby interp running called program
DIR => absolute directory of file (can use for relative requires)
it’s always easy get a relative path from an absolute one, but not the other
way!
cheers.
-a
On Sat, 1 May 2004, Simon Strandgaard wrote:
“Ara.T.Howard” ahoward@fattire.ngdc.noaa.gov wrote:
–
===============================================================================
EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
PHONE :: 303.497.6469
ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
URL :: Solar-Terrestrial Physics Data | NCEI
TRY :: for l in ruby perl;do $l -e “print "\x3a\x2d\x29\x0a"”;done
===============================================================================
Then $0 would need to be absolute too.
So the question is, would, could switching the default $0 setting and
FILE to absolute paths break existing programs?
Are there Windows considerations that could cause problems? Cygwin?
MinGW?
I’m considering writing up an RCR, but before I put Matz and myself
through all that, I want to make sure we’re not wasting time.
On 2004 Apr 30, at 12:04, Ara.T.Howard wrote:
i think it makes perfect sense to have
FILE => absolute path of script file
PROGRAM => absolute path of called program
RUBY => absolute path of ruby interp running called program
DIR => absolute directory of file (can use for relative
requires)it’s always easy get a relative path from an absolute one, but not the
other
way!
–
Ryan “John” Platte
Custom services, NIKA Consulting
http://nikaconsulting.com/
[snip]
I don’t know if all this rethinking FILE/$0 makes sense…
i think it makes perfect sense to have
FILE => absolute path of script file
PROGRAM => absolute path of called program
RUBY => absolute path of ruby interp running called program
DIR => absolute directory of file (can use for relative requires)it’s always easy get a relative path from an absolute one, but not the other
way!
This was what I wanted to express, though I could not write it in such a striking
sentence
I don’t know what is right nor wrong…
Maybe make FILE a class with a one useful method, #standalone?
So that instead of ‘if $0 == FILE’ you can type ‘if FILE.standalone?’
Maybe make a System class, containing a $0 replacement?
What does other languages do ?
“Ara.T.Howard” ahoward@fattire.ngdc.noaa.gov wrote:
On Sat, 1 May 2004, Simon Strandgaard wrote:
–
Simon Strandgaard
You are right… I were to quick to rid of $0… of cause some kind of
replacement are needed.
$0 is a mixup to me, it mixes
A) invocation path.
B) program name, which ps/top can use.
Two different things to me.
But I have no ideas to what an eventual replacement could be like.
BTW: I have submitted an RCR about the FILE problem.
http://rcrchive.net/rcr/RCR/RCR250
“Robert Klemme” bob.news@gmx.net wrote:
“Simon Strandgaard” neoneye@adslhome.dk schrieb im Newsbeitrag
I think its time to rethink FILE and get rid of $0.
I certainly disagree here: $0 never changes automatically during the
lifetime of a script while FILE reflects the current file. That’s an
important distinction in the light of require and load. Just imagine a
help module that automatically prints invocation hints…
–
Simon Strandgaard
i think it makes perfect sense to have
FILE => absolute path of script file
PROGRAM => absolute path of called program
RUBY => absolute path of ruby interp running called program
DIR => absolute directory of file (can use for relative
requires)it’s always easy get a relative path from an absolute one, but not the
other
way!Then $0 would need to be absolute too.
snoopy vars are on the way out - that’s what PROGRAM is (in theory)…
So the question is, would, could switching the default $0 setting and
FILE to absolute paths break existing programs?
perhaps it should then be:
$SCRIPT_FILE => absolute path of script file
$PROGRAM_NAME => absolute path of called program
$RUBY => absolute path of ruby interp running called program
$BASE_DIR => absolute directory of file (can use for relative
or (VAR - take your pick)
and this breaks no current code (probably).
now that i think about it, if you are putting an RCR together it might make
sense to create a namespace for the notion of ‘stuff specific to this instance
of ruby’ and put all this stuff in there. something like
require ‘rbconfig’
require ‘pathname’
module Runtime
SCRIPT_FILE = Pathname.new(FILE).realpath.to_s
PROGRAM_NAME = Pathname.new($0).realpath.to_s
RUBY = File.join Config::CONFIG[‘bindir’], Config::CONFIG[‘RUBY_INSTALL_NAME’]
BASE_DIR = File.dirname SCRIPT_FILE
end
or perhaps implement the namespace as in
ENV[‘RUBY_SCRIPT_FILE’] = Pathname.new(FILE).realpath.to_s
who knows…
all i’m saying is, if a namespace was inforced we could put all sorts of
useful stuff in there w/o breaking old code.
Are there Windows considerations that could cause problems? Cygwin?
MinGW?I’m considering writing up an RCR, but before I put Matz and myself
through all that, I want to make sure we’re not wasting time.
-a
On Sat, 1 May 2004, John Platte wrote:
On 2004 Apr 30, at 12:04, Ara.T.Howard wrote:
–
===============================================================================
EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
PHONE :: 303.497.6469
ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
URL :: Solar-Terrestrial Physics Data | NCEI
TRY :: for l in ruby perl;do $l -e “print "\x3a\x2d\x29\x0a"”;done
===============================================================================
“Simon Strandgaard” neoneye@adslhome.dk schrieb im Newsbeitrag
news:20040501024546.78ef9b57.neoneye@adslhome.dk…
[snip]
I don’t know if all this rethinking FILE/$0 makes sense…
i think it makes perfect sense to have
FILE => absolute path of script file
PROGRAM => absolute path of called program
RUBY => absolute path of ruby interp running called program
DIR => absolute directory of file (can use for relative
requires)
DIR is superfluous if FILE is absolute alreay. File.dirname(
FILE ) will do the job.
And I’d choose different names. The FILE and LINE are there
because of CPP, there’s no need to use these kind of names for new
semantics.
it’s always easy get a relative path from an absolute one, but not the
other
way!This was what I wanted to express, though I could not write it in such a
striking
sentence
I don’t think that statement is true. For both approaches (rel path →
abs path and abs path → rel path) you need an additional piece of
information, an additional path to relate to. That said, both (the
relative path and the absolute path) lack information, which makes it
equally difficult to do the transformation (or let’s say impossible
without this additional information).
I don’t know what is right nor wrong…
Maybe make FILE a class with a one useful method, #standalone?
So that instead of ‘if $0 == FILE’ you can type ‘if
FILE.standalone?’
I don’t have statistics but this may brake too much code.
Maybe make a System class, containing a $0 replacement?
I like the idea. Maybe call it Runtime. This could even be facilitated
in creating nested but independent interpreters etc.:
Runtime.current.interpreter
=> /usr/bin/ruby
Runtime.current.gc
=> 1023 (collected instances)
Runtime.current.used_mem
=> 12828379478
Runtime.new( “my_script.rb”, “–verbose”, “foo” )
=> Runtime
Regards
robert
“Ara.T.Howard” ahoward@fattire.ngdc.noaa.gov wrote:
On Sat, 1 May 2004, Simon Strandgaard wrote: