add python implementation of pali (thanks arland!)

pali.py

@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+
+import ctypes, sys, struct
+
+memory = [0]*65536
+here = 0
+pointers = {}
+
+
+def extract_code(code):
+  ret = ''
+  comment = True
+  for i in code.split('\n'):
+    if i == '~~~':
+      comment = comment == False
+    elif not comment:
+      ret += i+'\n'
+  return ret
+
+
+ops = [ '..', 'li', 'du', 'dr', 'sw', 'pu',
+        'po', 'ju', 'ca', 'cc', 'cj', 're',
+        'eq', 'ne', 'lt', 'gt', 'fe', 'st',
+        'ad', 'su', 'mu', 'di', 'an', 'or',
+        'xo', 'sl', 'sr', 'cp', 'cy', 'io' ]
+
+def comment(a):
+  pass
+
+def origin(a):
+  global here
+  here = int(a)
+
+def intw(a):
+  global memory, here
+  memory[here] = int(ctypes.c_int32(int(a)).value)
+  here += 1
+
+def bundle(a):
+  A = ops.index(a[0:2])
+  B = ops.index(a[2:4])
+  C = ops.index(a[4:6])
+  D = ops.index(a[6:8])
+  intw((D<<24)+(C<<16)+(B<<8)+A)
+
+def spacer(a):
+  global here
+  here += int(a)
+
+def sstr(a):
+  intw(len(a))
+  for c in a:
+    intw(ord(c))
+
+def zstr(a):
+  for c in a:
+    intw(ord(c))
+  intw(0)
+
+def ref(a):
+  if a in pointers:
+    intw(pointers[a])
+  else:
+    intw(0)
+
+def iref(a):
+  if a in pointers:
+    intw(-1 * pointers[a])
+  else:
+    intw(0)
+
+def label(a):
+  global pointers
+  pointers[a] = here
+
+def rc(code):
+  global here
+  here = 0
+  ops = {
+          'c': comment,
+          'o': origin,
+          'i': bundle,
+          'd': intw,
+          '*': spacer,
+          's': sstr,
+          'z': zstr,
+          'r': ref,
+          'R': iref,
+          '-': ref,
+          ':': label
+  }
+  for line in code.split('\n'):
+    if ' ' in line.lstrip():
+      op,a = line.lstrip().split(' ', 1)
+      ops[op](a)
+
+def save_image():
+  with open("ilo.rom", "wb") as f:
+    f.write(struct.pack('65536i', *memory[:65536]))
+
+def pali(code):
+  code = extract_code(code)
+  rc(code) #pre processing
+  rc(code) #post processing
+  print('{} words ({} bytes) used'.format(here, here*4))
+
+if __name__ == '__main__':
+  a = sys.argv
+  if len(a) > 1:
+    with open(a[1], 'r') as code:
+      pali(code.read())
+      save_image()
+  else:
+    with open('pali.output', 'w') as f:
+      pali(input('paste in Pali code:\n'))
+      save_image()