2to3 pattern matching help needed.

[Lennart Regebro]

Help! I need a pattern to match the following code:

@implementor(IFoo)
class C(object):
implements(IFoo)
classProvides(IFooFactory

find_pattern claims that this code should match:

"decorated< decorator< '@' 'implementer' '(' 'IFoo' ')' '\n' >
classdef< 'class' 'C' '(' 'object' ')' ':' suite< '\n' ' '
simple_stmt< power< 'implements' trailer< '(' 'IFoo' ')' > > '\n' >
simple_stmt< power< 'classProvides' trailer< '(' 'IFooFactory' ')' > >
'\n' > '' > > >"

It does not match.


I already have the following similar pattern:

"classdef< 'class' any* ':' suite< any* simple_stmt< power<
statement=(%s) trailer < '(' interface=any ')' > any* > any* > any* >

"

which matches the following code:

class C(object):
implements(IFoo)
classProvides(IFooFactory

I.e, the same code but without the decorator. But I also need to match
even of the class has decorators, as in the beginning example. If the
decorator matching code is the same or a separate that the one I have,
that doesn't handle decorators, doesn't matter.

[Benjamin Peterson]

Post by Lennart Regebro
@implementor(IFoo)
   implements(IFoo)
   classProvides(IFooFactory
classdef< 'class' 'C' '(' 'object' ')' ':' suite< '\n' '    '
simple_stmt< power< 'implements' trailer< '(' 'IFoo' ')' > > '\n' >
simple_stmt< power< 'classProvides' trailer< '(' 'IFooFactory' ')' > >
'\n' > '' > > >"
It does not match.

2to3 has a hard time working with more than a single statements and
lines of code especially classes. You can't use the pattern matcher
for everything, unfortunately. This pattern matches a class with the
decorator you want:

decorated< decorator< '@' 'implementor' '(' 'IFoo' ')' any >
class=classdef< any* > >

Once you that matches, I suggest you traverse the classdef node
programmatically to find simple_stmts containing the lines you're
interested in. This is similar to what lib2to3/fixes/fix_metaclass.py
does.

[Lennart Regebro]

Post by Benjamin Peterson

Post by Lennart Regebro
@implementor(IFoo)
   implements(IFoo)
   classProvides(IFooFactory
classdef< 'class' 'C' '(' 'object' ')' ':' suite< '\n' '    '
simple_stmt< power< 'implements' trailer< '(' 'IFoo' ')' > > '\n' >
simple_stmt< power< 'classProvides' trailer< '(' 'IFooFactory' ')' > >
'\n' > '' > > >"
It does not match.

2to3 has a hard time working with more than a single statements and
lines of code especially classes. You can't use the pattern matcher
for everything, unfortunately. This pattern matches a class with the
class=classdef< any* > >
Once you that matches, I suggest you traverse the classdef node
programmatically to find simple_stmts containing the lines you're
interested in. This is similar to what lib2to3/fixes/fix_metaclass.py
does.

Well, that didn't help, but it made me realize I was barking up the
wrong three. The problem was that I created a new node tree that
wasn't what it would have looked like like if it had been parsed from
source (although it would generate valid code when made into a str). I
fixed that, and did some other changes, and I got past this obstacle
too.

Tricky stuff this.