How to enable %cython magic function in sage terminal mode?

edit

Here is what worked for me. First I create a file:

/home/mike/cython.spyx

with the following contents:

cdef class c_class:
    cdef int number
    def __init__(self, n):
        self.number = n
    cpdef show(self):
        print('The number was: %s' %self.number)

Then I start up sage:

sage: version()
'Sage Version 4.5.1, Release Date: 2010-07-19'
sage: load '/home/mike/cython.spyx'
Compiling /home/mike/cython.spyx...
sage: instance = c_class(5)
sage: instance.show()
The number was: 5

-- I hope this is readable. This is the first question I've tried to answer and I'm having a little trouble with the formatting :-)

-Mike

There currently isn't any way to have a "%cython" mode at the command-line. One could imagine using IPython's magic commands, but they seem to just take a single line of input which isn't that useful when writing Cython code. Honestly, your best option is to do something like Mike Witt posted above and write the Cython code in a separate file and use the load or attach commands to load it into your command-line session.

Check out the cython command that is available by default in Sage. It does what you want and I think it happens to be the command that I used to implement the%cython mode in the notebook.

sage: cython?
....
       Given a block of Cython (Sage's variant of Pyrex) code (as a text
       string), this function compiles it using your C compiler, and
       includes it into the global scope of the module that called this
       function.
sage: cython('def f(double n): return n*n')
sage: f(292908234982340982)
8.5795234120470249e+34

Here is a longer example:

sage: cython("""
....: def f(int i):
....:     cdef int j
....:     for j in range(i):
....:         i += j
....:     return i
....: """)
sage: f(100)
5050
sage: timeit('f(100)')
625 loops, best of 3: 465 ns per loop