I find the following behaviour a little bizarre: At the macirb prompt (0.8) fileManager = NSFileManager.defaultManager @theProjectRoot = '/Users/martin/work/macruby/lots_of_files' => "/Users/martin/work/macruby/lots_of_files"
filenames = fileManager.contentsOfDirectoryAtPath(@theProjectRoot, error:nil).map {|f| theProjectRoot.stringByAppendingPathComponent(f) } NameError: undefined local variable or method `theProjectRoot' for main:TopLevel
If I create a local variable with the name theProjectRoot, then the statement runs correctly. According to the documentation, NSFileManager.defaultManager.contentsOfDirectoryAtPath requires a string; the scope of the variable should be irrelevant, shouldn't it?
The problem you are seeing is because inside the #map block you don't reference the project root variable as an instance variable, but as a local variable. Hence the error “undefined local variable or method `theProjectRoot'” :) If you change the block like this, all should be good: map {|f| @theProjectRoot.stringByAppendingPathComponent(f) } On Jan 27, 2011, at 10:18 AM, Martin Hawkins wrote:
I find the following behaviour a little bizarre: At the macirb prompt (0.8) fileManager = NSFileManager.defaultManager @theProjectRoot = '/Users/martin/work/macruby/lots_of_files' => "/Users/martin/work/macruby/lots_of_files"
filenames = fileManager.contentsOfDirectoryAtPath(@theProjectRoot, error:nil).map {|f| theProjectRoot.stringByAppendingPathComponent(f) } NameError: undefined local variable or method `theProjectRoot' for main:TopLevel
If I create a local variable with the name theProjectRoot, then the statement runs correctly. According to the documentation, NSFileManager.defaultManager.contentsOfDirectoryAtPath requires a string; the scope of the variable should be irrelevant, shouldn't it?
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Yes - a 1.9 change; 'parameters to a block are now always local to a block' - I'll probably forget again before it sticks. On Jan 27, 9:44 am, Eloy Durán <eloy.de.en...@gmail.com> wrote:
The problem you are seeing is because inside the #map block you don't reference the project root variable as an instance variable, but as a local variable. Hence the error “undefined local variable or method `theProjectRoot'” :)
If you change the block like this, all should be good:
map {|f| @theProjectRoot.stringByAppendingPathComponent(f) }
On Jan 27, 2011, at 10:18 AM, Martin Hawkins wrote:
I find the following behaviour a little bizarre: At the macirb prompt (0.8) fileManager = NSFileManager.defaultManager @theProjectRoot = '/Users/martin/work/macruby/lots_of_files' => "/Users/martin/work/macruby/lots_of_files"
filenames = fileManager.contentsOfDirectoryAtPath(@theProjectRoot, error:nil).map {|f| theProjectRoot.stringByAppendingPathComponent(f) } NameError: undefined local variable or method `theProjectRoot' for main:TopLevel
If I create a local variable with the name theProjectRoot, then the statement runs correctly. According to the documentation, NSFileManager.defaultManager.contentsOfDirectoryAtPath requires a string; the scope of the variable should be irrelevant, shouldn't it?
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I think you’re thinking about an unrelated change in 1.9, which is this: % ruby -e 'x = 42; lambda { |x| x = 21 }.call(x); p x' 21 % ruby19 -e 'x = 42; lambda { |x| x = 21 }.call(x); p x' 42 In your example ‘theProjectRoot’ is not a parameter to the block, that's ‘f’. It could have been a local variable (or method) outside of the block, but that isn't so either, the one variable you defined that comes close is the instance variable named ‘@theProjectRoot’. I hope this explains it better. If not feel free to ask more :) On Jan 27, 2011, at 2:26 PM, Martin Hawkins wrote:
Yes - a 1.9 change; 'parameters to a block are now always local to a block' - I'll probably forget again before it sticks.
On Jan 27, 9:44 am, Eloy Durán <eloy.de.en...@gmail.com> wrote:
The problem you are seeing is because inside the #map block you don't reference the project root variable as an instance variable, but as a local variable. Hence the error “undefined local variable or method `theProjectRoot'” :)
If you change the block like this, all should be good:
map {|f| @theProjectRoot.stringByAppendingPathComponent(f) }
On Jan 27, 2011, at 10:18 AM, Martin Hawkins wrote:
I find the following behaviour a little bizarre: At the macirb prompt (0.8) fileManager = NSFileManager.defaultManager @theProjectRoot = '/Users/martin/work/macruby/lots_of_files' => "/Users/martin/work/macruby/lots_of_files"
filenames = fileManager.contentsOfDirectoryAtPath(@theProjectRoot, error:nil).map {|f| theProjectRoot.stringByAppendingPathComponent(f) } NameError: undefined local variable or method `theProjectRoot' for main:TopLevel
If I create a local variable with the name theProjectRoot, then the statement runs correctly. According to the documentation, NSFileManager.defaultManager.contentsOfDirectoryAtPath requires a string; the scope of the variable should be irrelevant, shouldn't it?
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On 28/01/2011, at 2:46 AM, Eloy Durán wrote:
In your example ‘theProjectRoot’ is not a parameter to the block, that's ‘f’. It could have been a local variable (or method) outside of the block, but that isn't so either, the one variable you defined that comes close is the instance variable named ‘@theProjectRoot’.
Or, to paraphrase, '@theProjectRoot' and 'theProjectRoot' are not the same variable. This trips me up quite often too :) Henry
participants (3)
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Eloy Durán
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Henry Maddocks
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Martin Hawkins