[IronPython] InteractiveCode and function definitions

[Curt Hagenlocher]

What I've done is to test explicitly for the blank line at the end in
conjuction with the test for ScriptCodeParseResult.IncompleteStatement:

completeThought = (result == ScriptCodeParseResult.Complete or
    result == ScriptCodeParseResult.Invalid or
    (result == ScriptCodeParseResult.IncompleteStatement and
text.endswith('\n\n')))

On Thu, Apr 16, 2009 at 10:54 AM, Michael Foord
<fuzzyman at voidspace.org.uk>wrote:

> Curt Hagenlocher wrote:
>
>> That's only because you've decided to arbitrarily[*] define "\n\n" as
>> being a signal to mean "complete".  That's not part of the actual language
>> specification.
>>
> It's the behaviour of the interactive interpreter though - which specifies
> something. It's also the specification adhered to by the code module for
> implementing interactive interpreters.
>
> In fact, if I append "\n\n  print 2\n\n" to that string, it's still a valid
>> Python program.  The key here is that "the user has entered a complete
>> thought" is a property of the interpreter and not of the language.  I might
>> well decide that the "commit" key sequence is Control+E (as it is in SQL
>> Server Management Studio) instead of "enter enter".
>>  My point is that it's not correct for IronPython to dictate the semantics
>> of your interpreter.
>>
>
> Fine, so do you have any suggestions as to how to replicate the behaviour
> of the interactive interpreter - whether or not it counts as a
> specification?
>
> Michael
>
>   [*] Okay, "arbitrary" is a bit strong in that it's what python.exe and
>> ipy.exe defines. :)
>>
>>  On Thu, Apr 16, 2009 at 10:36 AM, Michael Foord <
>> fuzzyman at voidspace.org.uk <mailto:fuzzyman at voidspace.org.uk>> wrote:
>>
>>    Curt Hagenlocher wrote:
>>
>>        "IncompleteStatement" means that the user is allowed to type
>>        more code.  If you want to know whether or not it's a valid
>>        (complete) string, just check for it not being Invalid.  A
>>        function definition is never "complete" in Python because
>>        there's never a terminating curly brace :).
>>
>>
>>    But that isn't sufficient to implement an interactive interpreter
>>    on top of. This code conceptually is complete as far as an
>>    interactive interpreter is concerned:
>>
>>
>>      'def f():\n  print 1\n\n'
>>
>>    It also means you can't distinguish between the previous kind of
>>    incomplete (which is incomplete because the user *could* type more
>>    code) and this kind of incomplete:
>>
>>      'a = """'
>>
>>    or:
>>
>>      'a = (1 + 2 +'
>>
>>    Which are both incomplete because the user *must* type more code.
>>    (Although the latter two give IncompleteToken - I wonder if that
>>    would be enough.)
>>
>>    Because of the other IronPython bugs we can't use the code module
>>    and ScriptSource / ScriptParseResult doesn't give sufficient
>>    information. Any other ideas?
>>
>>    Michael
>>
>>
>>        On Thu, Apr 16, 2009 at 10:05 AM, Michael Foord
>>        <fuzzyman at voidspace.org.uk <mailto:fuzzyman at voidspace.org.uk>
>>        <mailto:fuzzyman at voidspace.org.uk
>>        <mailto:fuzzyman at voidspace.org.uk>>> wrote:
>>
>>           Hello guys,
>>
>>           We're trying to detect whether a section of code is
>>        complete (to
>>           mimic the behaviour of the interactive interpreter).
>>
>>           First of all we tried using the Python standard library code
>>           module which provides interactive console classes. There
>>        are two
>>           outstanding bugs on codeplex (one reported by me today) which
>>           prevent this being an ideal solution:
>>
>>
>> http://ironpython.codeplex.com/WorkItem/View.aspx?WorkItemId=22064
>>
>> http://ironpython.codeplex.com/WorkItem/View.aspx?WorkItemId=21881
>>
>>           The second approach was to create a ScriptSource and looking at
>>           the code properties to tell if the statement is complete or not
>>           (using IronPython 2.0.1). However we can never get it to
>>        return a
>>           ScriptParseResult.Complete for function definitions. Code below
>>           shows using \n for newlines but we have also tried with \r\n.
>>
>>           >>> import clr
>>           >>> clr.AddReference('IronPython')
>>           >>> clr.AddReference('Microsoft.Scripting')
>>           >>> from IronPython.Hosting import Python
>>           >>> from Microsoft.Scripting import SourceCodeKind,
>>           ScriptCodeParseResult
>>           >>>
>>           >>> engine = Python.CreateEngine()
>>           >>> s = engine.CreateScriptSourceFromString('def f():\n  print
>>           1\n', 'foo', SourceCodeKind.InteractiveCode)
>>           >>> s.GetCodeProperties()
>>           <Microsoft.Scripting.ScriptCodeParseResult object at
>>           0x000000000000003F [IncompleteStatement]>
>>           >>> s = engine.CreateScriptSourceFromString('def f():\n  print
>>           1\n\n', 'foo', SourceCodeKind.InteractiveCode)
>>           >>> s.GetCodeProperties()
>>           <Microsoft.Scripting.ScriptCodeParseResult object at
>>           0x0000000000000040 [IncompleteStatement]>
>>           >>>
>>
>>           The DLR hosting spec has little helpful to say on the matter as
>>           far as I can tell.
>>
>>           Looking at an example from Tomas it doesn't seem very different
>>           from what we're doing:
>>
>>           http://blog.tomasm.net/2009/04/15/python-says-hello-to-ruby/
>>
>>           Any clues as to what we are doing wrong or how to procede?
>>
>>           Thanks
>>
>>           Michael
>>
>>           --    http://www.ironpythoninaction.com/
>>           http://www.voidspace.org.uk/blog
>>
>>
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>>    http://www.voidspace.org.uk/blog
>>
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> http://www.voidspace.org.uk/blog
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