p_error parameters lack information

[Robert Grosse]

One can define a p_error function to handle syntax errors, but
unfortunately, Ply provides no useful information to the function. I've had
to resort to an ugly reflection hack just to provide meaningful error
messages. Would it be possible to improve the interface so that Ply
actually provides access to this information?

def p_error(p):
if p is None:
print "Syntax error: unexpected EOF"
else:
print "Syntax error at line {}: unexpected token
{}".format(p.lineno, p.value)

#Ugly hack since Ply doesn't provide any useful error information
import inspect
frame = inspect.currentframe()
cvars = frame.f_back.f_locals
print 'Expected:', ', '.join(cvars['actions'][cvars[
'state']].keys())
print 'Found:', cvars['ltype']
print 'Current stack:', cvars['symstack']

[David Beazley]

In the GIT repository for PLY, I refactored a bit of the error
handling code to simplify a few things, but I think I could be
convinced to expand it a bit more.    Let me think about how I would
handle it.   Perhaps p_error() handling could be expanded to support
an optional second argument in which the parser instance would be
passed.   Certainly open to design ideas on this.
Cheers,Dave

----- Original Message -----
From: ply-***@googlegroups.com
To:
Cc:
Sent:Sun, 28 Oct 2012 19:15:14 -0700 (PDT)
Subject:p_error parameters lack information

One can define a p_error function to handle syntax errors, but
unfortunately, Ply provides no useful information to the function.
I've had
to resort to an ugly reflection hack just to provide meaningful
error
messages. Would it be possible to improve the interface so that Ply
actually provides access to this information?

def p_error(p):
    if p is None:
        print "Syntax error: unexpected EOF"
    else:
        print "Syntax error at line {}: unexpected token
{}".format(p.lineno [1], p.value) [2]

    #Ugly hack since Ply doesn't provide any useful error
information
    import inspect
    frame = inspect.currentframe() [3]
    cvars = frame.f_back.f_locals
    print 'Expected:', ',
'.join(cvars['actions'][cvars['state']].keys())
    print 'Found:', cvars['ltype']
    print 'Current stack:', cvars['symstack']

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Links:
------
[1] http://p.lineno
[2] http://sitemail.hostway.com/http:
[3] http://sitemail.hostway.com/http:
[4] mailto:ply-***@googlegroups.com
[5] mailto:***@googlegroups.com
[6] https://groups.google.com/d/msg/ply-hack/-/lohTjGaPdqgJ
[7] https://groups.google.com/groups/opt_out

[Erez]

I think that's a great idea.

I would not add an argument to p_error, because that would break
backwards-compatibility.
Perhaps you could add a new method with extended information. Like
p_error_verbose(p, actions, state, stack)

(or if you wish to allow more information in the future, p_error_verbose(p,
error_info_dict) )

In the GIT repository for PLY, I refactored a bit of the error handling
code to simplify a few things, but I think I could be convinced to expand
it a bit more. Let me think about how I would handle it. Perhaps
p_error() handling could be expanded to support an optional second argument
in which the parser instance would be passed. Certainly open to design
ideas on this.
Cheers,
Dave
----- Original Message -----
Sun, 28 Oct 2012 19:15:14 -0700 (PDT)
p_error parameters lack information
One can define a p_error function to handle syntax errors, but
unfortunately, Ply provides no useful information to the function. I've had
to resort to an ugly reflection hack just to provide meaningful error
messages. Would it be possible to improve the interface so that Ply
actually provides access to this information?
print "Syntax error: unexpected EOF"
print "Syntax error at line {}: unexpected token
{}".format(p.lineno, p.value)
#Ugly hack since Ply doesn't provide any useful error information
import inspect
frame = inspect.currentframe()
cvars = frame.f_back.f_locals
print 'Expected:', ', '.join(cvars['actions'][cvars[
'state']].keys())
print 'Found:', cvars['ltype']
print 'Current stack:', cvars['symstack']
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For more options, visit https://groups.google.com/groups/opt_out.

[David Beazley]

I like the idea of having an p_error_verbose() function.     That's
definitely doable.  I'll work on it.
Cheers,Dave
----- Original Message -----
From: ply-***@googlegroups.com
To:
Cc:"David Beazley"
Sent:Tue, 30 Oct 2012 04:09:54 -0700 (PDT)
Subject:Re: p_error parameters lack information

I think that's a great idea.
I would not add an argument to p_error, because that would break
backwards-compatibility.Perhaps you could add a new method with
extended information. Likep_error_verbose(p, actions, state, stack)
(or if you wish to allow more information in the future,
p_error_verbose(p, error_info_dict) ) 

On Tuesday, October 30, 2012 12:56:38 AM UTC+2, David Beazley
wrote:In the GIT repository for PLY, I refactored a bit of the error
handling code to simplify a few things, but I think I could be
convinced to expand it a bit more.    Let me think about how I would
handle it.   Perhaps p_error() handling could be expanded to support
an optional second argument in which the parser instance would be
passed.   Certainly open to design ideas on this
Cheers,Dave

----- Original Message -----
From: ply-***@googlegroups.com
To:
Cc:
Sent:Sun, 28 Oct 2012 19:15:14 -0700 (PDT)
Subject:p_error parameters lack information

One can define a p_error function to handle syntax errors, but
unfortunately, Ply provides no useful information to the function.
I've had
to resort to an ugly reflection hack just to provide meaningful
error
messages. Would it be possible to improve the interface so that Ply
actually provides access to this information?

def p_error(p):
    if p is None:
        print "Syntax error: unexpected EOF"
    else:
        print "Syntax error at line {}: unexpected token
{}".format(p.lineno [1], p.value)

    #Ugly hack since Ply doesn't provide any useful error
information
    import inspect
    frame = inspect.currentframe()
    cvars = frame.f_back.f_locals
    print 'Expected:', ',
'.join(cvars['actions'][cvars['state']].keys())
    print 'Found:', cvars['ltype']
    print 'Current stack:', cvars['symstack']

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To view this discussion on the web visit
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[3].
 
 

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[5].
 
 


Links:
------
[1] http://p.lineno
[2] https://groups.google.com/d/msg/ply-hack/-/lohTjGaPdqgJ
[3] https://groups.google.com/groups/opt_out
[4] https://groups.google.com/d/msg/ply-hack/-/noXUP4KKaOgJ
[5] https://groups.google.com/groups/opt_out

[Robert Grosse]

Why not make it take **kwargs rather than error_info_dict? That way it can
easily be extended while allowing people to ignore arguments they don't
care about.

I like the idea of having an p_error_verbose() function. That's
definitely doable. I'll work on it.
Cheers,
Dave
----- Original Message -----
Tue, 30 Oct 2012 04:09:54 -0700 (PDT)
Re: p_error parameters lack information
I think that's a great idea.
I would not add an argument to p_error, because that would break
backwards-compatibility.
Perhaps you could add a new method with extended information. Like
p_error_verbose(p, actions, state, stack)
(or if you wish to allow more information in the future,
p_error_verbose(p, error_info_dict) )

In the GIT repository for PLY, I refactored a bit of the error handling
code to simplify a few things, but I think I could be convinced to expand
it a bit more. Let me think about how I would handle it. Perhaps
p_error() handling could be expanded to support an optional second argument
in which the parser instance would be passed. Certainly open to design
ideas on this.
Cheers,
Dave
----- Original Message -----
Sun, 28 Oct 2012 19:15:14 -0700 (PDT)
p_error parameters lack information
One can define a p_error function to handle syntax errors, but
unfortunately, Ply provides no useful information to the function. I've had
to resort to an ugly reflection hack just to provide meaningful error
messages. Would it be possible to improve the interface so that Ply
actually provides access to this information?
print "Syntax error: unexpected EOF"
print "Syntax error at line {}: unexpected token
{}".format(p.lineno, p.value)
#Ugly hack since Ply doesn't provide any useful error information
import inspect
frame = inspect.currentframe()
cvars = frame.f_back.f_locals
print 'Expected:', ', '.join(cvars['actions'][cvars[
'state']].keys())
print 'Found:', cvars['ltype']
print 'Current stack:', cvars['symstack']
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