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pkp: po alternative to lookup via valueForKeyPath: #53

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Merged
kastiglione merged 4 commits into from
Nov 25, 2014
Merged

pkp: po alternative to lookup via valueForKeyPath: #53

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ce3dc97
Initial version of pkp, a command to print out via keypaths
Nov 20, 2014
5ccee16
Add an error message, made class invocation more durable.
Nov 20, 2014
72adcb4
Fix help message, clean up python.
Nov 21, 2014
bea8bee
If there's no '.', just pass the command to po, and evaluate the firs…
Nov 22, 2014
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26 changes: 26 additions & 0 deletions commands/FBPrintCommands.py
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ def lldbcommands():
FBPrintOnscreenTableViewCells(),
FBPrintInternals(),
FBPrintInstanceVariable(),
FBPrintKeyPath(),
]

class FBPrintViewHierarchyCommand(fb.FBCommand):
Expand Down Expand Up @@ -272,3 +273,28 @@ def run(self, arguments, options):

printCommand = 'po' if ('@' in ivarTypeEncodingFirstChar) else 'p'
lldb.debugger.HandleCommand('{} (({} *)({}))->{}'.format(printCommand, objectClass, object, ivarName))

class FBPrintKeyPath(fb.FBCommand):
def name(self):
return 'pkp'

def description(self):
return "Print out the value of [self valueForKeyPath:<>]."

@kastiglione kastiglione Nov 21, 2014

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The use of self here is misleading. To offer a possible wording:

Print out the value of the key path expression using -valueForKeyPath:.


def args(self):
return [
fb.FBCommandArgument(arg='keypath', type='NSString *', help='The keypath to print'),
]

def run(self, arguments, options):
keys = arguments[0].split('.')

if keys.count == 1:
print '"' + arguments[0] + '" is not a keypath =('

@kastiglione kastiglione Nov 21, 2014

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What do you think about treating this case as equal to po? That way, we can all type pkp except when evaluating something fancy.

@KingOfBrian KingOfBrian Nov 21, 2014

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It's an interesting idea, to add durable-ness, but I think it'd need a lot more checks than the presence of a '.' to be worth implementing. IE, [UIApplication sharedApplication].keyWindow would still blow up. I'd rather blow up in all slightly-wrong scenarios just keep clarity of intent.

@kastiglione kastiglione Nov 22, 2014

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See my other comment. Personally, while debugging, I'd rather make things as convenient as possible :)

@KingOfBrian KingOfBrian Nov 22, 2014

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Yea, looking at it again, I totally agree.

return

object = keys[0]
keys = keys[1:len(keys)]
keypath = ".".join(keys)

@kastiglione kastiglione Nov 21, 2014

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I liked the previous way, using split('.', 1), makes the above 3 lines a one liner, and still allows for handling the case where there is no key path.

@KingOfBrian KingOfBrian Nov 21, 2014

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My python is terrible. Cleaned it up a tad. I also see the possibility of stepping through the key path in python and asking the object if it responds, and the stepping, or printing a good error message if it doesn't respond.

@kastiglione kastiglione Nov 22, 2014

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My python is terrible.

Don't worry, Chisel was written by objc developers :)

I also see the possibility of stepping through the key path in python and asking the object if it responds, and the stepping, or printing a good error message if it doesn't respond.

💵

Ooh! It would even allow typos correction if we queried inspected the selectors on an object and found the nearest match.

@KingOfBrian KingOfBrian Nov 22, 2014

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So I added some basic stepping through the key path, but an object can return a value from -valueForKey: and return false from -respondsToSelector:. So I'm not sure this will work without some more thought. There's no -respondsToKey: functionality.

I'm not sure if you use FuzzyAutocomplete, but that does perform a good deal of completion/typo fixes when using po (when it works). pkp does not get the auto-completion help like po does though. Any idea how that could be fixed?

@kastiglione kastiglione Nov 22, 2014

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Thanks for looking into it! It's probably diminishing returns to implement walking the key path.

printCommand = 'po [(NSObject *){} valueForKeyPath:@"{}"]'.format(object, keypath)
lldb.debugger.HandleCommand(printCommand)