Validating Syntax only with PyParser_SimpleParseString ?

[gaston.gloesener@web.de]

I am seeking for a method to parse single lines of Python code (infact
they are only formulas, so I generate a line like RESULT=<formula >). I
do only want to know if the syntax is correct and if there is an error
best would be to know where.

I did find PyParser_Simple ParseString which does return a node
structure. If there is an error it seems to return NULL, while I did
not find this documented.

Th eproblem with this is that first I do not get th elopcation of the
syntax error, and second I don't know what is the proper method to free
the node structure after I got it, since I will not use it. Or is there
any better method doing this anyway.

Environment: Windows / Borland C++

[Fuzzyman]

Re: Validating Syntax only with PyParser_Simple ParseString ?


gaston.gloesene r@web.de wrote:[color=blue]
> I am seeking for a method to parse single lines of Python code (infact
> they are only formulas, so I generate a line like RESULT=<formula >). I
> do only want to know if the syntax is correct and if there is an error
> best would be to know where.
>
> I did find PyParser_Simple ParseString which does return a node
> structure. If there is an error it seems to return NULL, while I did
> not find this documented.
>
> Th eproblem with this is that first I do not get th elopcation of the
> syntax error, and second I don't know what is the proper method to free
> the node structure after I got it, since I will not use it. Or is there
> any better method doing this anyway.
>[/color]
A better way might be to use the standard library compiler module. A
file called cptools.py (part of the cherrypy project) has a very simple
example called 'unrepr' which shows how to do it.

I only have restricted internet access or I would find the URL for you
(sorry).

Fuzzyman
http://www.voidspace.org.uk/python/index.shtml
[color=blue]
> Environment: Windows / Borland C++[/color]

[olsongt@verizon.net]

Re: Validating Syntax only with PyParser_Simple ParseString ?


gaston.gloesene r@web.de wrote:[color=blue]
> I am seeking for a method to parse single lines of Python code (infact
> they are only formulas, so I generate a line like RESULT=<formula >). I
> do only want to know if the syntax is correct and if there is an error
> best would be to know where.
>
> I did find PyParser_Simple ParseString which does return a node
> structure. If there is an error it seems to return NULL, while I did
> not find this documented.
>
> Th eproblem with this is that first I do not get th elopcation of the
> syntax error, and second I don't know what is the proper method to free
> the node structure after I got it, since I will not use it. Or is there
> any better method doing this anyway.
>
> Environment: Windows / Borland C++[/color]

The builtin function compile will throw a SyntaxError if the syntax is
bad.
[color=blue][color=green][color=darkred]
>>> compile("1=a"," ","single")[/color][/color][/color]
Traceback (most recent call last):
File "<interacti ve input>", line 1, in ?
SyntaxError: can't assign to literal[color=blue][color=green][color=darkred]
>>>[/color][/color][/color]

[gaston.gloesener@web.de]

Re: Validating Syntax only with PyParser_Simple ParseString ?

Thanks for th eanswers so far.

But as you can see from the function I use, I do need an interface
function to do th ejob from C++. I canno timagine there is no clean way
to do this. Calling th epython interpreter to execute a compule
function in python and then get the output parsed to get th eerror
message i snot an option. The strange thing however is that I have
tried to use th ecompile interface function first and this one did
return an error. I supposed this was because th ewhole context did not
exist so I went to the "parse only" function.

The main question I have is what to do with the pointer to the node
structure returned by this function, as freeing th epointer with free()
throws an error.