Wow, things have suddenly turned very negative. I understand that this is very normal for these types of forums where it is easy to lose sight of the big picture. So let me try to refocus this discussion again.
MOTIVATION The way the scientific and engineering communities predominately write real numbers is by using SI scale factors. These numbers almost always represent physical quantities, so it is common to write the number with scale factor and units. So for example, the distance to Andromeda is 780kpc, the pressure at the bottom of the Mariana Trench is 108MPa, the total power produced by a typical hurricane is 600TW, the number of base pairs in human DNA is 3.2Gb, and the Bohr radius is 53pm. These numbers are the language of science and engineering, but in recent years they have also entered the realm of popular culture. For example, an article by Ars Technica that calculates that the value of the music that can fit on a classic iPod as over $8G (that is the total penalty that can be accessed if they were all stolen copyright works). http://arstechnica.com/tech-policy/2012/06/from-gigabytes-to-petadollars-copyright-math-begets-copyright-currency/ In all of these examples the numbers are either very large or very small, and they employ the use of SI scale factors to make them easy to write and communicate. This way of writing numbers is so well established that it was formally standardized as part of the International System of Units (the Système international d'unités) in 1960. The problem is that most general purpose programming languages do not support this way of writing numbers. Instead they force people to convert the numbers to and from exponential notation, which is rather inconvenient and hard to read, write, say, or hear (it is much easier to say or hear 53 picometers than 5.3e-11 meters). When working with a general purpose programming language, the above numbers become: 780kpc -> 7.8e+05 108MPa -> 1.08e+08 600TW -> 6e+14 3.2Gb -> 3.2e+09 53pm -> 5.3e-11 $8G -> 8e+09 Notice that the numbers become longer, harder to read, harder to type, harder to say, and harder to hear. NEXT STEP So the question is, should Python accommodate this widely used method of writing real numbers? Python already has many ways of writing numbers. For example, Python allows integers to be written in binary, octal, decimal and hex. Any number you can write in one form you can write in another, so the only real reason for providing all these ways is the convenience of the users. Don't Python's users in the scientific and engineering communities deserve the same treatment? These are, after all, core communities for Python. Now, Python is a very flexible language, and it is certainly possible to add simple libraries to make it easy to read and write numbers with SI scale factors. I have written such a library (engfmt). But with such libraries this common form of writing numbers remains a second class citizen. The language itself does not understand SI scale factors, instead any time you want to input or output numbers in their natural form you must manually convert them yourself. Changing Python so that it understands SI scale factors on real numbers as first class citizens innately requires a change to the base language; it cannot be done solely through libraries. The question before you is, should we do it? The same question confronted the developers of Python when it was decided to add binary, octal and hexadecimal number support to Python. You could have done it with libraries, but you didn't because binary, octal and hexadecimal numbers were too common and important to be left as second class citizens. Well, use of binary, octal and hexadecimal numbers is tiny compared to the use of real numbers with SI scale factors. Before we expend any more effort on this topic, let's put aside the question of how it should be done, or how it will be used after its done, and just focus on whether we do it at all. Should Python support real numbers specified with SI scale factors as first class citizens? What do you think? -Ken _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
