Re: [gentoo-dev] [New eclass] twisted-r1.eclass

[Alex Xu <alex_y_xu@yahoo.ca>]

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On 03/08/13 02:29 PM, Michał Górny wrote:
> Dnia 2013-08-03, o godz. 17:54:42
> Ulrich Mueller <ulm@gentoo.org> napisał(a):
> 
>>>>>>> On Sat, 3 Aug 2013, Michał Górny wrote:
>>
>>> 2. The eclass comes with a pure bash-3.2 CamelCase converter for
>>> changing PNs like 'twisted-foo' into 'TwistedFoo'. The relevant code
>>> can be moved to eutils as portable replacements for bash-4 ${foo^}
>>> and friends.
>>
>>> 		# obtain octal ASCII code for the first letter.
>>> 		local ord=$(printf '%o' "'${fl}")
>>>
>>> 		# check if it's [a-z]. ASCII codes are locale-safe.
>>> 		if [[ ${ord} -ge 141 && ${ord} -le 172 ]]; then
>>> 			# now substract 040 to make it upper-case.
>>> 			# fun fact: in range 0141..0172, decimal '- 40' is fine.
>>> 			local ord=$(( ${ord} - 40))
>>> 			# and convert it back to the character.
>>> 			fl=$(printf '\'${ord})
>>> 		fi
>>
>> This looks just horrible. You do decimal arithmetic on octal numbers?
> 
> Yes. Bash wasn't really happy to do octal arithmetic for me. Yet
> in this particular case, with proper assumptions, decimal arithmetic is
> practically equivalent.
> 

		# obtain decimal ASCII code for the first letter.
		local fl=$(printf '%d' "'${w}")

		# check if it's [a-z]. ASCII codes are locale-safe.
		if [[ ${ord} -ge 97 && ${ord} -le 122 ]]; then
			local ord=$(( ${ord} - 32 ))
			# and convert it back to the character.
			fl=$(printf '\'${ord})
		fi

		echo -n "${fl}${w:1}"

Probably var names should be adjusted, I'm not too familiar with bash
locals.

printf '%d' "'twisted" outputs "116" as expected, similar to
printf("%d", *"asdf qwerty") in C.

Tested in Bash 4.2.45.

Now time to sit back and wait for it to break in bash
<obscure-version-here>.


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