[IronPython] Newbie: convert string to python expression??

[Kristian Jaksch]

Orestis,

passing the 'context' to 'eval' seems like the right thing to do. I tried
your solution, see below:

*
clr.AddReference("Mapack, Version=1.0.0.0, Culture=neutral,
PublicKeyToken=null")

from Mapack import **    * #A library that contain classes for working with
algebra etc.*
.
.
.
*context = {}

def inputBox_KeyDown(s, e):
  key = e.Key.value__
  result = root.inputBox.Text
  if key == 3: #If 'Enter' key is pressed
       try:
           try:
               root.message.Text = eval(result, globals(), locals())
           except SyntaxError:
              exec(result, globals(), locals())
       except Exception, e:
           print 'Unhandled exception', e
       root.inputBox.Text = "" #Clearing inputBox

*If I then define my matrix (as always): I type *m=Matrix(2,2)* in
'inputBox' and I don't receive any exceptions so I assume the definition is
ok. But if I type *print m* I get an exception: "m is not defined". Why is
that?


Michael,

What do you mean exec the import * inside the context to poulate it?
Something like:

*context['Mapack'] = exec "from Mapack import *"   #Doesn't work

*Hmmm... think I'm getting tired.

Anyway thanks for help!



2008/12/16 Michael Foord <fuzzyman at voidspace.org.uk>

> Michael Foord wrote:
>
>> Kristian Jaksch wrote:
>>
>>> *
>>> def inputBox_KeyDown(s, e):
>>>  key = e.Key.value__
>>>  result = root.inputBox.Text
>>>  if key == 3: #If 'Enter' key is pressed
>>>      try:
>>>          try:
>>>              root.message.Text = eval(result)
>>>          except SyntaxError:
>>>             exec result in context
>>>      except Exception, e:
>>>          print 'Unhandled exception', e
>>>      root.inputBox.Text = "" #Clearing inputBox*
>>>
>>> But this creates a fixed size matrix and I still get an exception if I
>>> type for example *m=Matrix(2,2)* in the 'inputBox'. I want to make this as
>>> general as possible. Can't I place everything that is imported from 'Mapack'
>>> into the 'context' dictionary together with whatever the user types in
>>> besides of that?
>>>
>>
>> You can. I'll give you a clue - import * makes it harder. Try importing
>> Mapack and then it will be easier to put things from the module into the
>> dictionary.
>>
>
> Hmmm - actually you could exec the import * inside the context to populate
> it.
>
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