Language Specification

This document specifies the Python subset supported by HOPE.

Native Types

The following native types are supported

  • bool
  • int
  • float

NumPy Types

The following NumPy types are supported

  • bool_
  • integer, signedinteger, byte, short, intc, intp, int0, int_, longlong
  • int8, int16, int32, int64
  • unsignedinteger, ubyte, ushort, uintc, uintp, uint0, uint_, ulonglong
  • uint8, uint16, uint32, uint64
  • single, float_
  • float32, float64
  • ndarray

Conditional Expressions

  • If
  • If/Else
  • If/ElseIf/Else


The while statement is supported as well as for loops but only with range(stop) or range(start, stop) resp. xrange:

for i in range(start, stop):

Return Statement

A function needs to have a fixed return type. HOPE currently supports scalar and array data types as return values.

The following code will not compile as the type of the return value may change depending on the execution:

def incompatible_return(arg):
    if arg > 10:
        return 1
        return 2.3 # ERROR: Inconsistent return type

Call functions

Call to pure Python functions are supported if the function

  • is accessible form the global scope of the function
  • has no decorators
  • only uses the subset of Python supported by HOPE
  • has no recursive or cyclic calls

Then the called function is also compiled to c++ and included in the shared object regardless where the function was defined originally.



Assign b = a

Unary operators

UAdd +a
USub -a

Binary operators

Add a + b
Sub a - b
Mult a * b
Div a / b
FloorDiv a // b
Pow a ** b
Mod a % b
LShift a << b
RShift a >> b
BitOr a | b
BitXor a ^ b
BitAnd a & b

Augmented assign statements

AugAdd a += b
AugSub a -= b
AugMult a *= b
AugDiv a /= b
AugFloorDiv a /= b
AugPow a **= b
AugMod a %= b
AugLShift a <<= b
AugRShift a <<= b
AugBitOr a | b
AugBitXor a ^ b
AugBitAnd a & b

Comparison Operators

Eq a == b
NotEq a != b
Lt a < b
LtE a <= b
Gt a > b
GtE a >= b

Bool Operators

&& a and b
|| a or b

NumPy Array creation routines

empty(shape[, dtype]) Return a new array of given shape and type, without initializing entries.
ones(shape[, dtype]) Return a new array of given shape and type, filled with ones.
zeros(shape[, dtype]) Return a new array of given shape and type, filled with zeros.

NumPy Mathematical functions

Trigonometric functions

sin(x) Trigonometric sine, element-wise.
cos(x) Cosine elementwise.
tan(x) Compute tangent element-wise.
arcsin(x) Inverse sine, element-wise.
arccos(x) Trigonometric inverse cosine, element-wise.
arctan(x) Trigonometric inverse tangent, element-wise.

Hyperbolic functions

sinh(x) Hyperbolic sine, element-wise.
cosh(x) Hyperbolic cosine, element-wise.
tanh(x) Compute hyperbolic tangent element-wise.

Exponents and logarithms

exp(x) Calculate the exponential of all elements in the input array.


sum(x) Return the sum of array elements.
sqrt(x) Return the positive square-root of an array, element-wise.
interp(x, xp, fp[, left, right]) One-dimensional linear interpolation.
ceil(x) Return the ceiling of the input, element-wise.
floor(x) Return the floor of the input, element-wise.
trunc(x) Return the truncated value of the input, element-wise.
pi Returns the pi constant
fabs Compute the absolute values element-wise
sign Returns an element-wise indication of the sign of a number

Attributes of numpy.ndarray

No attributes are supported at the moment


  • Added cast operators for np.bool_, np.int_, np.intc, np.int8, np.int16, np.int32, np.int64, np.uint8, np.uint16, np.uint32, np.uint64, np.float_, np.