On 3 January 2012 20:38, Terry Reedy <tjre...@udel.edu> wrote: > On 1/3/2012 1:13 PM, Sean Wolfe wrote: > > I have a theoretical / philosophical question regarding strong vs duck >> typing in Python. Let's say we wanted to type strongly in Python and >> > > Python objects are strongly typed, in any sensible meaning of the term. > What you mean is statically or explicitly typing names. > > > were willing to compromise our code to the extent necessary, eg not >> changing variable types or casting or whatever. Let's say there was a >> methodology in Python to declare variable types. >> >> The question is, given this possibility, would this get us closer to >> being able to compile down to a language like C or C++? >> > > Cython compiles Python as is to C. It also gives the option to add type > annotations to names to get faster code. Shredskin compiles a subset of > Python, or a subset of usages, to C, with similar benefits.
A minor point of clarification here: although what you wrote is technically true, it's also misleading. AFAIK both Cython and Shedskin compile only a subset of Python, but the magnitude difference they drop off is large. Almost everything is Cython compliant, and that should just grow, but there are a few flakes here and there. However, Shedskin is a well defined subset, and does not encompass the whole of Python and will never do so. Shedskin *truly* compiles to C and thus is afflicted with several restrictions such as static typing. Cython is a lot less clear. What it compiles to is basically bytecode written in C. Instead of CPython reading the bytecode and the bytecode being parsed and then executed, *the computer natively parses the bytecode which tells CPython what to do*. This reduces a lot of overhead in tight loops, but doesn't help much in the general case. So why sacrifice so much for so little gain? Well - when your bytecode is C, you can interoperate other C code right inside. If you make some C variables you can do C-math inside your Python with no real overhead. Additionally, you can call C libraries really easily inside this code. What it results in is a really easy way to optimise the 5% that's slowing your code, and instead of rewriting it in C you use C-with-python-syntax. The types are sill horrible, though ;) -------------------------------------- To answer Devin: You're probably thinking of Cython ^^.
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