KUAL: Kindle Unified Application Launcher (v2.7) - Page 7

knc1 · 01-22-2013, 08:36 AM

Quote:

Originally Posted by stepk

Define as local what for? I mean what's your concern if it isn't defined as local? IFS is a special shell variable, local or global it affects the way sh works. Note that json_parse sets it the resets to its default value when it's finished.

1) Keeps the changes to IFS local to the function ;
2) Does not assume an error-free code path ;
3) Is a matter of good style ;

4) You can drop that "resets it to the default value" thing ;
4.a) Which might be an error - a function can't be certain it was set to the default value on entry ;
4.b) The value of IFS will be the same on exit as on entry.

stepk · 01-22-2013, 08:50 AM

@twobob: working on your requested changes
@kc1: instead of dropping the reset to default value I'd rather save and restore the on-entry IFS value, just to bracket exactly the region where IFS=, needs to be in place. Any comments?

knc1 · 01-22-2013, 08:51 AM

Quote:

Originally Posted by stepk

@twobob: working on your requested changes
@kc1: instead of dropping the reset to default value I'd rather save and restore the on-entry IFS value, just to bracket exactly the region where IFS=, needs to be in place. Any comments?

That is exactly what:
local IFS
does for you - no need to add any executable statements.

twobob · 01-22-2013, 08:51 AM

Quote:

Originally Posted by stepk

@twobob: working on your requested changes
@kc1: instead of dropping the reset to default value I'd rather save and restore the on-entry IFS value, just to bracket exactly the region where IFS=, needs to be in place. Any comments?

Superb.

Sound fine mate. Heroic even.

twobob · 01-22-2013, 09:00 AM

as a "use case"

Quote:

# create pretty label
make_label () {
echo -n "$json_name ¬$json_action $json_params"
## or echo -n "$xml_name ¬$json_action $json_params"
echo
}

would be a likely test...

knc1 · 01-22-2013, 09:14 AM

Sorry folks, not time to explain this morning, but . . . .

Another thing to control in the source is enable/disable "glob expansion" in the functions when using IFS and/or the built-in string operations.

Keeps the dumb-dumb scripting language from trying (first) to turn the word expansion into a path or file name on the storage media.

stepk · 01-22-2013, 09:16 AM

Quote:

Originally Posted by knc1

That is exactly what:
local IFS
does for you - no need to add any executable statements.

I didn't explain myself exactly. json_parse calls a user-provided function - make_label in this case. I want for the user-provided function to get an unmodified IFS. So I need to reset IFS before calling the user's function from within json_parse, don't I?

Code:

json_parse() {
local IFS0=$IFS IFS ... foo=$2
...
IFS=,
...
IFS=$IFS0
$foo
...
}

or is the local scoping not affecting called subs?
Also is it safe to save $IFS and declare it local in a single statement, or should I break it into two lines

Code:

local IFS0=$IFS
local IFS ...

thanks

stepk · 01-22-2013, 09:28 AM

Quote:

Originally Posted by twobob

as a "use case"

echo -n "$json_name ¬$json_action $json_params"

would be a likely test...

Done. Will attach soon, here's what I get on my extensions. Not too pretty in some cases. IMO you need to prefix $xml_name and condense some of the $json_name's... Give instructions, I will do

Spoiler:

edit: the forum is hiding multiple spaces in '| Run Gray' and similar labels...

twobob · 01-22-2013, 09:51 AM

Yeah. EDIT -> GO ADVANCED -> and like # (code blocks)

[code] stuff [/ code]

As to your suggestions on name creation, feel free to implement your own suggestions.
This is still just in the "testing" phase. I'm happy to take on suggestions, no doubt Ixtab would think the same thing.

Thanks : )

stepk · 01-22-2013, 09:57 AM

Quote:

Originally Posted by knc1

Sorry folks, not time to explain this morning, but . . . .

Another thing to control in the source is enable/disable "glob expansion" in the functions when using IFS and/or the built-in string operations.

Keeps the dumb-dumb scripting language from trying (first) to turn the word expansion into a path or file name on the storage media.

Will do, thanks. I'm puzzled

Code:

x=${s/[ \t][ \t]/ }

KT sh seems to think that "\t " means a t followed by a space/t while I intended \t as the tab character. Isn't \t a recognized escape? If not, how can I specify tab in that context? ... going to study

edit: comes back... got it from your minimodding guide; use $'\t' instead of \t.

knc1 · 01-22-2013, 10:06 AM

Quote:

Originally Posted by stepk

I didn't explain myself exactly. json_parse calls a user-provided function - make_label in this case. I want for the user-provided function to get an unmodified IFS. So I need to reset IFS before calling the user's function from within json_parse, don't I?

Code:

json_parse() {
local IFS0=$IFS IFS ... foo=$2
...
IFS=,
...
IFS=$IFS0
$foo
...
}

or is the local scoping not affecting called subs?
Also is it safe to save $IFS and declare it local in a single statement, or should I break it into two lines

Code:

local IFS0=$IFS
local IFS ...

thanks

Yes, you want that - since you shouldn't guess a what an external function might expect.

I really must run (car keys in hand) - but . . . .
Here is a (somewhat large) example (in BASH!) of the handling of a lot of those issues:
http://hg.minimodding.com/repos/cats/shacat.hg/

In particular the topmost defines for the IFS strings.
That way a reader will get a clue as to what is happening at each step along the way.

twobob · 01-22-2013, 10:09 AM

if it isn't on this page? http://linux.about.com/library/cmd/blcmdl1_ash.htm
Then I probably don't know it. Since my knowledge of scripting is postage stamp sized and my knowledge of ash is covered by that page.
I too however am diving into some more docs.

I'll give http://hg.minimodding.com/repos/cats...3/sha1cat.bash a look too

twobob · 01-22-2013, 10:24 AM

err... is it like $'\t' ( so maybe something to do with the context of the escaping?)

[root@kindle extensions]# echo "Hey$'\t'You!" <- nope

Quote:

Hey'\t'You!

[root@kindle extensions]# echo Hey$'\t'You! <- yep?

Quote:

Hey You!

EDIT: LOL! I see you found it.

knc1 · 01-22-2013, 10:25 AM

Quote:

Originally Posted by twobob

I'll give http://hg.minimodding.com/repos/cats...3/sha1cat.bash a look too

That program is three lines long + one line to output all failure messages. (see tail end of the script)

The fact that it takes 1200+ lines of supporting functions...
Well, whatever.

It can (has done) 1Tbyte disk drives with things nested in arbitrary order. (zips of tars of gzips of whatever).
Any combination of the expand_<thing> that is posssible.

I.E: My "Declarative Programming in Bash" example first published in the ABS Guide ten years ago.

twobob · 01-22-2013, 11:10 AM

Quote:

Originally Posted by knc1

...first published in the ABS Guide ten years ago.

Old != Bad

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01-22-2013, 08:50 AM	#92
stepk Groupie Posts: 165 Karma: 593460 Join Date: Oct 2012 Device: K5 B011 5.3.2.1	@twobob: working on your requested changes @kc1: instead of dropping the reset to default value I'd rather save and restore the on-entry IFS value, just to bracket exactly the region where IFS=, needs to be in place. Any comments?

01-22-2013, 09:14 AM	#96
knc1 Going Viral Posts: 17,212 Karma: 18210809 Join Date: Feb 2012 Location: Central Texas Device: No K1, PW2, KV, KOA	Sorry folks, not time to explain this morning, but . . . . Another thing to control in the source is enable/disable "glob expansion" in the functions when using IFS and/or the built-in string operations. Keeps the dumb-dumb scripting language from trying (first) to turn the word expansion into a path or file name on the storage media.

01-22-2013, 09:51 AM	#99
twobob ( ͡° ͜ʖ ͡°){ʇlnɐɟ ƃǝs}Týr Posts: 6,586 Karma: 6299993 Join Date: Jun 2012 Location: uti gratia usura (Yao ying da ying; Mo ying da yieng) Device: PW-WIFI\|K5-3G+WIFI\| K4\|K3-3G\|DXG\|K2\| Rooted Nook Touch	Yeah. EDIT -> GO ADVANCED -> and like # (code blocks) [code] stuff [/ code] As to your suggestions on name creation, feel free to implement your own suggestions. This is still just in the "testing" phase. I'm happy to take on suggestions, no doubt Ixtab would think the same thing. Thanks : )

01-22-2013, 10:09 AM	#102
twobob ( ͡° ͜ʖ ͡°){ʇlnɐɟ ƃǝs}Týr Posts: 6,586 Karma: 6299993 Join Date: Jun 2012 Location: uti gratia usura (Yao ying da ying; Mo ying da yieng) Device: PW-WIFI\|K5-3G+WIFI\| K4\|K3-3G\|DXG\|K2\| Rooted Nook Touch	if it isn't on this page? http://linux.about.com/library/cmd/blcmdl1_ash.htm Then I probably don't know it. Since my knowledge of scripting is postage stamp sized and my knowledge of ash is covered by that page. I too however am diving into some more docs. I'll give http://hg.minimodding.com/repos/cats...3/sha1cat.bash a look too

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