| Case Insensitive Hash but still preserve cases of original keys [message #89000] |
Sun, 13 July 2014 23:24  |
SonicKenking
Messages: 51
Registered: October 2010
|
Member |
|
|
Hello Community,
I tried to implement a special Hash object with following features
1. Keys are of String type
2. Keys should be case insensitive
3. The original cases of keys should be preserved and reported when the keys() method is called.
Let's say it is called SpeicalHash. It should support following operations:
h = SpecialHash()
h['X'] = 42
print, h.keys() ; output 'X'
print, h['x'], h['X'] ; output 42, 42
print, h.haskey('x'), h.haskey('X') ; output 1, 1
h['x'] = 1337
print, h['x'], h['X'] ; output 1337, 1337
I came up with an implementation (attached at the end of this post) and it meets all of the above requirements. However, when I tried to print the variable h, it reports error of "Key does not exist"
print, h ; Output % Key does not exist: "X"
I found out the PRINT command calls Hash::_overloadPrint to do the job and it in turn calls Keys() method to get the keys. I guess that is where the key "X" comes in. However, I don't understand how PRINT gets the value of a key because none of the overload Bracket methods are called (the cases of keys are taken care of in SpecialHash's bracket methods). I can only think of two possibilities:
1. The Hash::_overloadPrint method calls Hash's own bracket methods to get the value of a key. Therefore the SpecialHash's bracket methods did not get called. If this is true, it seems to be a bug in IDL's Hash implementation and should be fixed.
2. The Hash::_overloadPrint method calls some other hidden method to get the value of a key. If this is the case, can someone show me how it is done?
Thanks!
Yang
; =============== SpecialHash Implementation Starts Here ==============
function SpecialHash::keys
return, list(self.keylist, /extract)
end
function SpecialHash::hasKey, _keys
keys = strlowcase(_keys)
return, self->Hash::hasKey(keys)
end
function SpecialHash::_overloadBracketsRightSide, isRange, $
sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
sub1 = strlowcase(sub1)
return, self->hash::_overloadBracketsRightSide(isRange, sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8)
end
pro SpecialHash::_overloadBracketsLeftSide, objref, value, isrange, $
_sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
sub1 = strlowcase(_sub1)
self->Hash::_overloadBracketsLeftSide, objref, value, isrange, sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
if (self->Hash::keys()).count() eq self.keylist.count() + 1 then self.keylist.add, _sub1
end
function SpecialHash::init
if ~self->Hash::init() then return, 0
self.keylist = list()
return, 1
end
pro SpecialHash__define
class = {SpecialHash, inherits hash, $
keylist: list() }
end
; =============== End of Code ==============
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| Re: Case Insensitive Hash but still preserve cases of original keys [message #89001 is a reply to message #89000] |
Sun, 13 July 2014 23:41  |
SonicKenking
Messages: 51
Registered: October 2010
|
Member |
|
|
On Monday, July 14, 2014 4:24:08 PM UTC+10, SonicKenking wrote:
> Hello Community,
>
>
>
> I tried to implement a special Hash object with following features
>
> 1. Keys are of String type
>
> 2. Keys should be case insensitive
>
> 3. The original cases of keys should be preserved and reported when the keys() method is called.
>
>
>
> Let's say it is called SpeicalHash. It should support following operations:
>
>
>
> h = SpecialHash()
>
> h['X'] = 42
>
> print, h.keys() ; output 'X'
>
> print, h['x'], h['X'] ; output 42, 42
>
> print, h.haskey('x'), h.haskey('X') ; output 1, 1
>
>
>
> h['x'] = 1337
>
> print, h['x'], h['X'] ; output 1337, 1337
>
>
>
> I came up with an implementation (attached at the end of this post) and it meets all of the above requirements. However, when I tried to print the variable h, it reports error of "Key does not exist"
>
>
>
> print, h ; Output % Key does not exist: "X"
>
>
>
> I found out the PRINT command calls Hash::_overloadPrint to do the job and it in turn calls Keys() method to get the keys. I guess that is where the key "X" comes in. However, I don't understand how PRINT gets the value of a key because none of the overload Bracket methods are called (the cases of keys are taken care of in SpecialHash's bracket methods). I can only think of two possibilities:
>
>
>
> 1. The Hash::_overloadPrint method calls Hash's own bracket methods to get the value of a key. Therefore the SpecialHash's bracket methods did not get called. If this is true, it seems to be a bug in IDL's Hash implementation and should be fixed.
>
>
>
> 2. The Hash::_overloadPrint method calls some other hidden method to get the value of a key. If this is the case, can someone show me how it is done?
>
>
>
> Thanks!
>
>
>
> Yang
>
>
>
> ; =============== SpecialHash Implementation Starts Here ==============
>
>
>
>
>
> function SpecialHash::keys
>
> return, list(self.keylist, /extract)
>
> end
>
>
>
> function SpecialHash::hasKey, _keys
>
> keys = strlowcase(_keys)
>
> return, self->Hash::hasKey(keys)
>
> end
>
>
>
> function SpecialHash::_overloadBracketsRightSide, isRange, $
>
> sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
>
>
>
> sub1 = strlowcase(sub1)
>
> return, self->hash::_overloadBracketsRightSide(isRange, sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8)
>
>
>
> end
>
>
>
> pro SpecialHash::_overloadBracketsLeftSide, objref, value, isrange, $
>
> _sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
>
>
>
> sub1 = strlowcase(_sub1)
>
> self->Hash::_overloadBracketsLeftSide, objref, value, isrange, sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
>
> if (self->Hash::keys()).count() eq self.keylist.count() + 1 then self.keylist.add, _sub1
>
>
>
> end
>
>
>
> function SpecialHash::init
>
> if ~self->Hash::init() then return, 0
>
> self.keylist = list()
>
> return, 1
>
> end
>
>
>
> pro SpecialHash__define
>
> class = {SpecialHash, inherits hash, $
>
> keylist: list() }
>
> end
>
>
>
>
>
> ; =============== End of Code ==============
Forgot to attach my version info
IDL> help, !version
** Structure !VERSION, 8 tags, length=104, data length=100:
ARCH STRING 'x86_64'
OS STRING 'Win32'
OS_FAMILY STRING 'Windows'
OS_NAME STRING 'Microsoft Windows'
RELEASE STRING '8.3'
BUILD_DATE STRING 'Nov 15 2013'
MEMORY_BITS INT 64
FILE_OFFSET_BITS
INT 64
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| Re: Case Insensitive Hash but still preserve cases of original keys [message #89002 is a reply to message #89000] |
Sun, 13 July 2014 23:53 |
Fabzi
Messages: 305
Registered: July 2010
|
Senior Member |
|
|
Hi,
On 14.07.2014 08:24, SonicKenking wrote:
> I tried to implement a special Hash object with following features
> 1. Keys are of String type
> 2. Keys should be case insensitive
> 3. The original cases of keys should be preserved and reported when the keys() method is called.
this sounds like a dictionary to me:
IDL> h = dictionary()
IDL> h['X'] = 42
IDL> print, h.keys()
X
IDL> print, h['x'], h['X']
42 42
IDL> print, h.haskey('x'), h.haskey('X')
1 1
IDL> h['x'] = 1337
IDL> print, h['x'], h['X'] ; output 1337, 1337
1337 1337
IDL> print, h.keys()
x
Cheers,
Fabien
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| Re: Case Insensitive Hash but still preserve cases of original keys [message #89003 is a reply to message #89000] |
Sun, 13 July 2014 23:57 |
SonicKenking
Messages: 51
Registered: October 2010
|
Member |
|
|
On Monday, July 14, 2014 4:24:08 PM UTC+10, SonicKenking wrote:
> Hello Community,
>
>
>
> I tried to implement a special Hash object with following features
>
> 1. Keys are of String type
>
> 2. Keys should be case insensitive
>
> 3. The original cases of keys should be preserved and reported when the keys() method is called.
>
>
>
> Let's say it is called SpeicalHash. It should support following operations:
>
>
>
> h = SpecialHash()
>
> h['X'] = 42
>
> print, h.keys() ; output 'X'
>
> print, h['x'], h['X'] ; output 42, 42
>
> print, h.haskey('x'), h.haskey('X') ; output 1, 1
>
>
>
> h['x'] = 1337
>
> print, h['x'], h['X'] ; output 1337, 1337
>
>
>
> I came up with an implementation (attached at the end of this post) and it meets all of the above requirements. However, when I tried to print the variable h, it reports error of "Key does not exist"
>
>
>
> print, h ; Output % Key does not exist: "X"
>
>
>
> I found out the PRINT command calls Hash::_overloadPrint to do the job and it in turn calls Keys() method to get the keys. I guess that is where the key "X" comes in. However, I don't understand how PRINT gets the value of a key because none of the overload Bracket methods are called (the cases of keys are taken care of in SpecialHash's bracket methods). I can only think of two possibilities:
>
>
>
> 1. The Hash::_overloadPrint method calls Hash's own bracket methods to get the value of a key. Therefore the SpecialHash's bracket methods did not get called. If this is true, it seems to be a bug in IDL's Hash implementation and should be fixed.
>
>
>
> 2. The Hash::_overloadPrint method calls some other hidden method to get the value of a key. If this is the case, can someone show me how it is done?
>
>
>
> Thanks!
>
>
>
> Yang
>
>
>
> ; =============== SpecialHash Implementation Starts Here ==============
>
>
>
>
>
> function SpecialHash::keys
>
> return, list(self.keylist, /extract)
>
> end
>
>
>
> function SpecialHash::hasKey, _keys
>
> keys = strlowcase(_keys)
>
> return, self->Hash::hasKey(keys)
>
> end
>
>
>
> function SpecialHash::_overloadBracketsRightSide, isRange, $
>
> sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
>
>
>
> sub1 = strlowcase(sub1)
>
> return, self->hash::_overloadBracketsRightSide(isRange, sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8)
>
>
>
> end
>
>
>
> pro SpecialHash::_overloadBracketsLeftSide, objref, value, isrange, $
>
> _sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
>
>
>
> sub1 = strlowcase(_sub1)
>
> self->Hash::_overloadBracketsLeftSide, objref, value, isrange, sub1, sub2, sub3, sub4, sub5, sub6, sub7, sub8
>
> if (self->Hash::keys()).count() eq self.keylist.count() + 1 then self.keylist.add, _sub1
>
>
>
> end
>
>
>
> function SpecialHash::init
>
> if ~self->Hash::init() then return, 0
>
> self.keylist = list()
>
> return, 1
>
> end
>
>
>
> pro SpecialHash__define
>
> class = {SpecialHash, inherits hash, $
>
> keylist: list() }
>
> end
>
>
>
>
>
> ; =============== End of Code ==============
A bit more findings:
This is most likely a bug in 8.3
I tried with 8.2.3 and I didn't get any error with "PRINT, h". As 8.3 added implied print, it is likely where the bug is introduced?
However, one more problem with both 8.2.3 and 8.3 is that the keys shown by PRINT is in wrong case:
IDL> h = SpecialHash()
IDL> h['X'] = 42
IDL> print, h
x: 42
NOTE the x displayed by PRINT is in lowercase while it really should be in uppercase.
The case is also wrong with FOREACH loop
IDL> foreach v,h,k do print, k,v
x 42
Scratching my head ...
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| Re: Case Insensitive Hash but still preserve cases of original keys [message #89004 is a reply to message #89002] |
Mon, 14 July 2014 00:02 |
SonicKenking
Messages: 51
Registered: October 2010
|
Member |
|
|
On Monday, July 14, 2014 4:53:53 PM UTC+10, Fabien wrote:
> Hi,
>
>
>
> On 14.07.2014 08:24, SonicKenking wrote:
>
>> I tried to implement a special Hash object with following features
>
>> 1. Keys are of String type
>
>> 2. Keys should be case insensitive
>
>> 3. The original cases of keys should be preserved and reported when the keys() method is called.
>
>
>
> this sounds like a dictionary to me:
>
>
>
> IDL> h = dictionary()
>
> IDL> h['X'] = 42
>
> IDL> print, h.keys()
>
> X
>
> IDL> print, h['x'], h['X']
>
> 42 42
>
> IDL> print, h.haskey('x'), h.haskey('X')
>
> 1 1
>
> IDL> h['x'] = 1337
>
> IDL> print, h['x'], h['X'] ; output 1337, 1337
>
> 1337 1337
>
> IDL> print, h.keys()
>
> x
>
>
>
> Cheers,
>
>
>
> Fabien
Hi Fabien,
Thanks for the reply. Unfortunately, Dictionary is not the solution in this case. Because the keys do not necessarily conform the naming rules of IDL variables, e.g. a key with white spaces "Some Key " or non-alphanumeric letter "<Key>".
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| Re: Case Insensitive Hash but still preserve cases of original keys [message #89015 is a reply to message #89014] |
Tue, 15 July 2014 05:32 |
Lajos Foldy
Messages: 176
Registered: December 2011
|
Senior Member |
|
|
On Tuesday, July 15, 2014 1:11:06 PM UTC+2, SonicKenking wrote:
> What I am confused is how PRINT gets the value for the key "X"? It seems to me that it should call something like self["X"], i.e. SpecialHash::_overloadBracketsRightSide. However it is not the case and this can be verified by setting a breakpoint as well.
There is an undocumented function hash::get:
IDL> print, (hash(0,0))[0]
0
IDL> .comp hash_get
% Compiled module: HASH::GET.
IDL> print, (hash(0,0))[0]
HASH::GET called: 0
0
IDL>
hash_get.pro is:
function hash::get, key, _extra=ext
print, 'HASH::GET called: ', key
return, 0
end
PRINT probably calls self.get(...), so you can try to add a SpecialHash::Get function.
regards,
Lajos
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