[pypy-dev] Help with Exception: unexpected prebuilt constant
Sorry for another newbish question, but I'm having trouble getting PyPy translated into C code. I added some calls to open() throughout the interpreter codebase (to log some info to files), but it failed translation with the following error: [translation:ERROR] Exception: unexpected prebuilt constant: built-in function open I then tried doing 'import os' and then using os.fdopen, but with the same error: [translation:ERROR] Exception: unexpected prebuilt constant: built-in function fdopen In general, what Python standard library calls can I make from my modified PyPy code and still have it translate properly? Specifically, how do I read/write files from within PyPy? Thanks! Philip ___ pypy-dev@codespeak.net http://codespeak.net/mailman/listinfo/pypy-dev
Re: [pypy-dev] Help with Exception: unexpected prebuilt constant
Hi Philip, Philip Guo wrote: Sorry for another newbish question, but I'm having trouble getting PyPy translated into C code. I added some calls to open() throughout the interpreter codebase (to log some info to files), but it failed translation with the following error: [translation:ERROR] Exception: unexpected prebuilt constant: built-in function open I then tried doing 'import os' and then using os.fdopen, but with the same error: [translation:ERROR] Exception: unexpected prebuilt constant: built-in function fdopen as you have noticed, neither os.open nor os.fdopen are supported by RPython. The only low-level supported way to deal with files is using os.open/os.read/os.write. However, you might want to have a look to rlib.streamio, that provides a higher level API to deal with files, offering features such as buffering, CR/LF conversions etc. In particular, you can use streamio.open_file_as_stream to get a file like object similar to the builtin python ones. In general, what Python standard library calls can I make from my modified PyPy code and still have it translate properly? Specifically, how do I read/write files from within PyPy? see above :-) ciao, Anto ___ pypy-dev@codespeak.net http://codespeak.net/mailman/listinfo/pypy-dev
Re: [pypy-dev] Help with Exception: unexpected prebuilt constant
Thanks for the informative reply, Antonio! My (probably dumb) follow-up question is: Is pickle (or cPickle) supported by RPython? The bottom line is that I need to serialize some data structures from my modified PyPy interpreter to disk so that data can persist across successive interpreter runs. Pickling is the most obvious way to do so, but it requires a Python built-in file object. If pickling doesn't work, what other way of persisting data on disk do you suggest? (e.g., printing it to a file as plaintext and then eval-ing it again? does eval() even work in RPython?) On Fri, Oct 9, 2009 at 1:46 AM, Antonio Cuni anto.c...@gmail.com wrote: Hi Philip, Philip Guo wrote: Sorry for another newbish question, but I'm having trouble getting PyPy translated into C code. I added some calls to open() throughout the interpreter codebase (to log some info to files), but it failed translation with the following error: [translation:ERROR] Exception: unexpected prebuilt constant: built-in function open I then tried doing 'import os' and then using os.fdopen, but with the same error: [translation:ERROR] Exception: unexpected prebuilt constant: built-in function fdopen as you have noticed, neither os.open nor os.fdopen are supported by RPython. The only low-level supported way to deal with files is using os.open/os.read/os.write. However, you might want to have a look to rlib.streamio, that provides a higher level API to deal with files, offering features such as buffering, CR/LF conversions etc. In particular, you can use streamio.open_file_as_stream to get a file like object similar to the builtin python ones. In general, what Python standard library calls can I make from my modified PyPy code and still have it translate properly? Specifically, how do I read/write files from within PyPy? see above :-) ciao, Anto ___ pypy-dev@codespeak.net http://codespeak.net/mailman/listinfo/pypy-dev
Re: [pypy-dev] Help with Exception: unexpected prebuilt constant
Philip Guo wrote: Thanks for the informative reply, Antonio! My (probably dumb) follow-up question is: Is pickle (or cPickle) supported by RPython? The bottom line is that I need to serialize some data structures from my modified PyPy interpreter to disk so that data can persist across successive interpreter runs. Pickling is the most obvious way to do so, but it requires a Python built-in file object. pickle and cpickle are not supported by RPython. If you need to serialize interp-level objects, I fear the only way is to manually write the code to write them to disk and read back. You might want to have a look at rlib.rmarshal, which can be used to serialize simple objects such as numbers, lists and tuples. On the other hand, remember that you have the whole PyPy python interpreter in your hands: depending on what you are trying to do, you could use it to interact with the fully working cPickle modules. But please notice that this solution works only if you want to serialize app-level objects (i.e. all the objects that are called as w_* inside the pypy sources). If pickling doesn't work, what other way of persisting data on disk do you suggest? (e.g., printing it to a file as plaintext and then eval-ing it again? does eval() even work in RPython?) no, eval() doesn't work in RPython. ciao, Anto ___ pypy-dev@codespeak.net http://codespeak.net/mailman/listinfo/pypy-dev
