Convert Python functions to PARI closures

AUTHORS:

Examples:

>>> def the_answer():
...     return 42
>>> import cypari2
>>> pari = cypari2.Pari()
>>> f = pari(the_answer)
>>> f()
42

>>> cube = pari(lambda i: i**3)
>>> cube.apply(range(10))
[0, 1, 8, 27, 64, 125, 216, 343, 512, 729]
cypari2.closure.objtoclosure(f)

Convert a Python function (more generally, any callable) to a PARI t_CLOSURE.

Note

With the current implementation, the function can be called with at most 5 arguments.

Warning

The function f which is called through the closure cannot be interrupted. Therefore, it is advised to use this only for simple functions which do not take a long time.

Examples:

>>> from cypari2.closure import objtoclosure
>>> def pymul(i,j): return i*j
>>> mul = objtoclosure(pymul)
>>> mul
(v1,v2)->call_python(v1,v2,0,0,0,2,...)
>>> mul(6,9)
54
>>> mul.type()
't_CLOSURE'
>>> mul.arity()
2
>>> def printme(x):
...     print(x)
>>> objtoclosure(printme)('matid(2)')
[1, 0; 0, 1]

Construct the Riemann zeta function using a closure:

>>> from cypari2 import Pari; pari = Pari()
>>> def coeffs(n):
...     return [1 for i in range(n)]
>>> Z = pari.lfuncreate([coeffs, 0, [0], 1, 1, 1, 1])
>>> Z.lfun(2)
1.64493406684823

A trivial closure:

>>> f = pari(lambda x: x)
>>> f(10)
10

Test various kinds of errors:

>>> mul(4)
Traceback (most recent call last):
...
TypeError: pymul() ...
>>> mul(None, None)
Traceback (most recent call last):
...
ValueError: Cannot convert None to pari
>>> mul(*range(100))
Traceback (most recent call last):
...
PariError: call_python: too many parameters in user-defined function call
>>> mul([1], [2])
Traceback (most recent call last):
...
PariError: call_python: forbidden multiplication t_VEC (1 elts) * t_VEC (1 elts)