[Cuis-dev] [IMPROV] Configurable command line exception handling

[Gerald Klix]

Hi Juan, Hi guys,

please find enclosed a simplified version of the command line parsing 
change set.
IHMO it is ready for integration.


Best Regards;

Gerald



On 1/12/23 9:01 PM, Gerald Klix wrote:
> Hi Juan,
>
> let me answer questions one at time (even those that were not asked:)
>
> -q) If want to write small Cuis scripts, like the prototypical “Hello 
> World” program, you would write  something like this:
>
> squeak  -vm-display-null -headless Cuis6.0-5626 -d "StdIOWriteStream 
> stdout nextPutAll: 'Hello World!'; newLine. Smalltalk quit"
>
> If you want to dump all unknown contributors to a file; it would look 
> like this:
>
> squeak  -vm-display-null -headless Cuis6.0-5626 -d  "Smalltalk 
> unknownContributors printOn: StdIOWriteStream stdout. Smalltalk quit" 
> > unknownContributors.txt
>
> Of course all these one-liners will end with `Smalltalk quit`, 
> therefore I came up with a shorter way to achieve the same effect:
>
> squeak  -vm-display-null -headless Cuis6.0-5626 -d  "Smalltalk 
> unknownContributors printOn: StdIOWriteStream stdout" -q > 
> unknownContributors.txt
>
> -c) is completely useless, because the old implementation only accepts 
> one `-s` option.
> `-s` consumes and copies all the remaining arguments to 
> `startUpScriptArguments`,
> terminating the loop,I did not catch that detail.
> I will fix this in the next version of the change.
>
> --) Posix requires a program to stop option parsing once it encounters 
> a double dash.
> To give an example that proves the necessity of this behavior, just 
> try this in your Mac's terminal:
>
> echo Hehehe > -f
>
> Than try to delete the file named “-f” using `rm -f`. This does not 
> work, you have to use `rm -- -f`.
> You can also check git, grep, ls or any other little Unix utility . 
> Just check:
>
> echo Hehehe > -r
> ls -r
>
> vs.
>
> ls -- -r
>
> (I leave it as an exercise to the gentle reader to get rid of that 
> '-r' file.)
>
> Therefore handling `--` should be done correctly, because it avoids 
> unnecessary surprises.
> But it also makes it easy to pass arguments to code package (classes) 
> that are
> installed with "-r". This part of Haver's installation package could 
> be written in a less hacky way:
>
> https://hg.sr.ht/~cy-de-fect/HaverOnCuis/browse/haver/Haverize.pck.st?rev=tip#L131 
>
>
> The same is true for the `-d` option, you can implement `echo` with 
> Cuis like this:
>
> squeak -vm-display-null -headless Cuis6.0-5626 -d  "Smalltalk 
> startUpScriptArguments do: [ :arg | StdIOWriteStream stdout 
> nextPutAll: arg; space]. StdIOWriteStream stdout newLine" -q -- -n 1 2 
> 3 a b dee
>
> compare to
>
> echo -- -n 1 2 3 a b dee
>
> Of course you want '--' handled correctly in your Cuis scripts, there 
> is no use
> in every author implementing it again, when she needs it.
>
>
> #copyStartupScriptArgumentsFrom:)
>
> Simply creates a fresh copy of the arguments after `--` for
> each script, code file, package or piece of code passed on the command 
> line.
>
> There is a reason for recreating the array for each script, code file 
> etc.:
> I never like the Unix's getopt(3) behavior.
> «By default, getopt() permutes the contents of argv as it scans,
> so that eventually all the nonoptions are at the end.»
> (https://www.man7.org/linux/man-pages/man3/getopt.3.html)
> Option parsing and program should no mess with the command line 
> arguments,
> this creates all sorts of nasty side effects.
>
> I hope I made my point about "end of options" and "--" clear.
> Please give some time to come up with a simpler version of the change.
>
>
> HTH,
>
> Gerald
>
>
> On 1/12/23 3:59 PM, Juan Vuletich wrote:
>> Hi Gerald,
>>
>> I agree that "do not ignore exceptions" doesn't need an argument. 
>> Then, maybe -e should never take an argument. I also like  -h and -v. 
>> Not sure about the value of -q, but I wouldn't mind including it.
>>
>> But can you explain -- and #copyStartupScriptArgumentsFrom: ? Can you 
>> give an example of use? I don't get it.
>>
>> Thanks,
>>
>> On 1/11/2023 6:53 PM, Gerald Klix via Cuis-dev wrote:
>>> Hi guys,
>>>
>>> thanks a lot for the encouraging feedback.
>>>
>>> It motivated me to to improve the exception
>>> ignoring stuff a bit; I just wanted '-e' to work without an argument.
>>> Then I noticed, that we can't handle options without arguments.
>>> Therefore I added, em well, some other options to the command line
>>> parsing code. I hope I haven't overdone it.
>>>
>>> You can now say `squeak Cuis.image -h` and get this output:
>>>
>>> --- snip --
>>> Command line options:
>>> -h Display this help message and quit
>>> -v Display the system information, containg the version and quit
>>> -q Just quit
>>> -e <exception> Evaluate exception and ignore it
>>> -e Set the exception to ignore to nil, i.e. do not ignore exceptions
>>> -r <feature> Require <feature>
>>> -d <code> Evaluate <code>
>>> -l <codeFile> Load e.g. file in <codeFile>
>>> -s <scriptFile> Evaluate code ein <scriptFile>
>>> -c Clear the array of start up script arguments
>>> -- end of options; stop processing options
>>>
>>> Arguments for scripts, code files, packages (and <code>):
>>> -s and -- store the remaining arguments in 'Smalltalk 
>>> startUpScriptArguments'
>>> -c clears the aforementioned array
>>> Packages (-f), code files (-l) and code (-d) gets a fresh copy of 
>>> the array if -- is present
>>>
>>> Multiple options:
>>> Options -e, -r, -d, -l, -s and -c can be passed multiple times
>>> --- snap ---
>>>
>>> Please review the change set and give me feedback.
>>> There might be some incompatibilities.
>>>
>>>
>>> HTH and Best Regards,
>>>
>>> Gerald
>>>
>>>
>>>
>>> On 1/11/23 2:33 PM, Dr. Nicola Mingotti wrote:
>>>> nice !
>>>>
>>>> Nicola
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On 1/8/23 17:21, Gerald Klix via Cuis-dev wrote:
>>>>> Hi all, Hi Juan,
>>>>>
>>>>> I was bit annoyed by the impossibility to debug scripts and packages
>>>>> run or installed from the command line.
>>>>> Therefore I added an option, ``-e <argument>``, that lets you
>>>>> set the exception class to handle before executing a script.
>>>>>
>>>>> With the attached change set, you can now write:
>>>>>
>>>>> squeak Cuis.image -e nil -s myScript.st
>>>>>
>>>>> If ``myScript.st`` contains an error, a Debugger
>>>>> will pop up.
>>>>>
>>>>>
>>>>> HTH and Best Regards,
>>>>>
>>>>> Gerald
>>>>>
>>>>
>>>
>>
>>
>

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