akalenuk/arrpl

Array processing library for Python inspired by APL

arrpl

Array processing library for Python inspired by APL

Basically you can work in Python and use APL-like monadic and diadic functions and operators to work on pythons lists. Like this:

A = [[1,2],[3,4]]
B = [7,8]
C = [2,1]

assert B -PLUS- 1 == [7, 8]
assert B -PLUS- C == [9, 9]

Python doesn't have operator overloading except for a predefined set, so in order to implement new words, I had to borrow an idea from Ferdinand Jamitzky. You shoud better check the code, it is better than any possible explanation. Long story short, functions (as in APL) ought to be surrounded by '-' signs, and operators (as in APL) - to be bounded with functions by '+' sign:

assert -PLUS+REDUCE- B == 15            # +/ B
assert (B -PLUS+INNER+MUL- C) == 22     # B +.× C 
assert (A -PLUS+INNER+MUL- A) == [[7, 10],[15,22]]  # A +.× A

The order of execution is left to right, as in Python, not like in APL:

assert ((-MINUS- 1) -PLUS- 2 -MUL- 3 -PLUS- [1, 2, 3]) == [4, 5, 6]

Generally, as you might wittness, it is not APL. It is Python with the some new syntax sweets.

So far I have implemented several functions:

PLUS
MINUS
MUL
DIV
MOD
POW

RANK      # ⍴
INDEX     # ⍳
MIRROR    # ⌽
WIRROR    # ⊖
TRANSPOSE # ⍉


NOT
AND
OR
LT
LE
EQ
GT
GE
NE
SELECT

And a few operators:

MAP
REDUCE
INNER
OUTER

Have fun!