I am sure someone has probably thought of this and there are good reasons why it is a bad idea or not possible, but, is there any technical reason why one couldn't somehow replace PRINT_ITEM byte code, with combination of byte codes which inserted in a reference to a file like object and then invoked PRINT_ITEM_TO byte code instead.
In other words, the aim is allow users code to use 'print' but change where the output goes when no target file is provided. I do know that one can replace sys.stdout with another file object in the simple case, or in the more complicated case with a file like object that determines where to redirect output based on the calling thread identity or some over criteria, but wanted to see if some one could do something without modifying sys.stdout. One particular example where I thought this might be interesting is to allow in a web templating system where Python code blocks can be embedded in markup, the use of the 'print' statement without a user having to know that they really need to direct output to a special file object, eg. 'print >> response'. Procedure might thus be to load Python code snippets and compile to byte code. Fixup byte code to change PRINT_ITEM to PRINT_ITEM_TO with other byte codes added to insert appropriate reference to file like object being supplied through data only passed to code object when executed. Cache code for ongoing use. Invoke code object as required, supplying reference to file object for output. In some template systems such as in web.py they replace sys.stdout with a magic object which based on the identity of the thread making calls to the methods of sys.stdout, will redirect the output back to a registered response object, but instead of doing it this way, could byte code manipulation provide another way. Anyway, just curious as to whether it would be possible or not and if someone has an example of doing it using byteplay or similar would love to see what is required. Graham -- http://mail.python.org/mailman/listinfo/python-list
