minimal_bindings.py

import ctypes

libfive = ctypes.cdll.LoadLibrary('build/libfive/src/libfive.dylib')

libfive.libfive_tree_x.restype = ctypes.c_void_p
libfive.libfive_tree_y.restype = ctypes.c_void_p

libfive.libfive_tree_delete.argtypes = [ctypes.c_void_p]

libfive.libfive_tree_binary.argtypes = [ctypes.c_int, ctypes.c_void_p, ctypes.c_void_p]
libfive.libfive_tree_binary.restype = ctypes.c_void_p

libfive.libfive_opcode_enum.argtypes = [ctypes.c_char_p]
libfive.libfive_opcode_enum.restype = ctypes.c_int

libfive.libfive_tree_const.argtypes = [ctypes.c_float]
libfive.libfive_tree_const.restype = ctypes.c_void_p

libfive.libfive_tree_print.argtypes = [ctypes.c_void_p]
libfive.libfive_tree_print.restype = ctypes.c_char_p

class Tree(object):
    def __init__(self, ptr):
        self.ptr = ptr
        
    def __del__(self):
        libfive.libfive_tree_delete(self.ptr)

    @staticmethod
    def x():
        return Tree(libfive.libfive_tree_x())

    @staticmethod
    def y():
        return Tree(libfive.libfive_tree_y())

    @staticmethod
    def const(f):
        return Tree(libfive.libfive_tree_const(f))

    @staticmethod
    def opcode(op):
        p = libfive.libfive_opcode_enum(op.encode('utf-8'))
        if p == -1:
            raise RuntimeError("Invalid opcode {}".format(op))
        return p

    def __add__(self, lhs):
        if not isinstance(lhs, Tree):
            lhs = self.const(lhs)

        return Tree(libfive.libfive_tree_binary(
            self.opcode('add'), self.ptr, lhs.ptr))

    def __radd__(self, rhs):
        if not isinstance(rhs, Tree):
            rhs = self.const(rhs)

        return Tree(libfive.libfive_tree_binary(
            self.opcode('add'), rhs.ptr, self.ptr))

    def __repr__(self):
        ''' WARNING: leaks the returned strings! '''
        return 'Tree<{}>'.format(
                libfive.libfive_tree_print(self.ptr).decode('utf-8'))

################################################################################

Python 3.7.0 (default, Jun 29 2018, 20:13:13)
Type 'copyright', 'credits' or 'license' for more information
IPython 6.4.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: %run python_minimal.py

In [2]: 12.5
Out[2]: 12.5

In [3]: 12.5 + Tree.x()
Out[3]: Tree<(+ 12.5 x)>

In [4]: Tree.x() + 15
Out[4]: Tree<(+ x 15)>

In [5]: Tree.x() + 15 + Tree.y()
Out[5]: Tree<(+ x 15 y)>