pytoj.py

import operator
from ctypes import *
'''
This is the Python to J script. This script needs to call libj.so functions and get the 
return values.
This is entirely based on the method here:
http://www.jsoftware.com/pipermail/programming/2013-November/033974.html 
'''
LIB = "../libj.so"
cmd = "cmd"

def mulall(arr):    
	return reduce(operator.mul,arr,1)

def run_jcmd( js):    
	j.JDo(p,cmd+' =: '+js)

def get_result(jdll,variable=cmd):    
	pi=[pointer(c_int()) for _ in xrange(4)]    
	j.JGetM(jdll,variable,*pi) 
	type=pi[0].contents.value    
	if type==0: #error        
		return None,None,None,None    
	rank=pi[1].contents.value    
	shape=list((c_int*rank).from_address(pi[2].contents.value))    
	flat_size=mulall(shape)    
	data=list((c_int*flat_size).from_address(pi[3].contents.value))
    	return type,rank,shape,resize(shape,data)

def res(jdll,var):
	pntrs = [pointer(c_int()) for _ in xrange(4)]
	j.JGetM(jdll,var,*pntrs)
	
	return list((c_int).from_address(pntrs[3].contents.value))

def resize(shap,dat):    
	shap=shap[:]    
	flat_size=mulall(shap)    
	while len(shap)>1:        
		shd=[]        
		start=0        
		last_size=shap.pop()        
		while start<flat_size:            
			shd.append(dat[start:start+last_size])            
			start+=last_size        
		flat_size=len(shd)        
		dat=shd    
	else:        	
		shd=dat    
	return shd



cdll.LoadLibrary(LIB)
j = CDLL(LIB)
p=j.JInit()


def ask_j(arg):
	run_jcmd("rez =: "+arg)
	return get_result(p, "rez") 

def setup_grid(size):
	run_jcmd("arr =: ([ ? #/~) "+str(size))
	return get_result(p, "arr")

def rotate_column(rotdir, colIndex):
	rs = list(str(rotdir))
	if rs[0] is '-':
		rs[0] = '_'
	rs = ''.join(rs)
	run_jcmd("arr =:("+rs+"|."+str(colIndex)+"{\"2 arr)"+str(colIndex)+"}\"2 arr")
	return get_result(p, "arr")

def rotate_row(rotdir, rowIndex):
	rs = list(str(rotdir))
        if rs[0] is '-':
                rs[0] = '_'
        rs = ''.join(rs)
        run_jcmd("arr =: |: ("+rs+"|."+str(rowIndex)+"{\"2 |: arr)"+str(rowIndex)+"}\"2 |: arr")
        return get_result(p, "arr")

def reflect():
	run_jcmd("arr =: |. arr")
	return get_result(p, "arr")

def transpose():
	run_jcmd("arr =: |: arr")
	return get_result(p, "arr")

def did_win():
	# we win if testing each row for equality of elements has no zeros.
	run_jcmd("win =: -. 0 e. , =\"1 arr")
	return get_result(p, "win")