Ethan Furman wrote:
Um -- how can you have on the one hand "completely not compatible" and
on the other "code that can cross-execute on either version"?
Great question ! .. .it has to do with education.
... if you learn 2.x (only) and attempt to program on the 3.x platform,
(without helps, education, migration tools, etc) you will fail... and
you will be frustrated. Why? 3.x is not compatible with 2.x knowledge.
If you learn 3.2 (only) and attempt to program on 2.x you will fail,
and you will be frustrated. Why? Because the two languages are
different and incompatible.
Now then, can you learn both?... sure. Can you migrate one to the
other with enough knowledge and effort?... yup. Is it possible (with
enough cleverness) to write code that will run on "both" without
modification... yes... Are the two languages compatible? No!
Where this really counts of course is real-world apps. It is relatively
easy to write trivial code blocks that demonstrate that nothing has
changed in 3.x/ ... and they are *all* misleading. The truth is that
hundreds of details have changed making the two 'versions' actually
different languages.
If I use the '89 version (1) K&R to write a C program, and compile it
on the current gcc without mods it will run. If I use the 2.5 python
manual to write a python program and try to run it on 3.2 it will fail
(for many, many reasons). This is my definition of completely
incompatible. The two languages are different; period.
The problem is that they "look" similar. :)
kind regards,
m harris
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