Subleq/subleq.py

← Back to Subleq

This is a public domain interpreter and simple assembler for Subleq, written in Python 3. It can assemble and run the Hello, world! example on the Subleq article.

#!/usr/bin/env python3
import sys
class Subleq:
 def __init__(self):
 self.mem = []
 def assemble(self, source_text):
 labels = self.collect_labels(source_text)
 self.write_contents(source_text, labels)
 def collect_labels(self, source_text):
 labels = {}
 def label_it(s, addr):
 if ':' in s:
 label, contents = s.split(':')
 labels[label] = addr
 addr = 0
 for line in source_text.split("\n"):
 line = line.strip()
 if not line or line.startswith('#'):
 continue
 [a, b, c] = line.split()
 label_it(a, addr)
 label_it(b, addr + 1)
 label_it(c, addr + 2)
 addr += 3
 return labels
 def write_contents(self, source_text, labels):
 def write_it(v, addr):
 if ':' in v:
 label, contents = v.split(':')
 v = contents
 if v in labels:
 v = labels[v]
 if v == '?+1':
 v = addr + 3
 self.mem.append(int(v))
 addr = 0
 for line in source_text.split("\n"):
 line = line.strip()
 if not line or line.startswith('#'):
 continue
 [a, b, c] = line.split()
 write_it(a, addr)
 write_it(b, addr)
 write_it(c, addr)
 addr += 3
 def dump_triples(self, f):
 addr = 0
 while addr < len(self.mem):
 a = self.mem[addr]
 b = self.mem[addr + 1] if addr + 1 < len(self.mem) else 0
 c = self.mem[addr + 2] if addr + 2 < len(self.mem) else 0
 f.write('{} {} {}\n'.format(a, b, c))
 addr += 3
 def load_triples(self, f):
 for line in f:
 a, b, c = line.split()
 self.mem.append(int(a))
 self.mem.append(int(b))
 self.mem.append(int(c))
 def run(self, trace=False):
 pc = 0
 while pc >= 0:
 a = self.mem[pc]
 b = self.mem[pc + 1]
 c = self.mem[pc + 2]
 if trace:
 print('pc={}, a={}, b={}, c={}'.format(pc, a, b, c))
 at_a = self.mem[a]
 if b >= 0:
 at_b = self.mem[b]
 result = at_b - at_a
 self.mem[b] = result
 elif b == -1:
 sys.stdout.write(chr(at_a))
 result = 0
 if result <= 0:
 pc = c
 else:
 pc += 3
def main(args):
 if len(args) == 3 and args[0] == 'assemble':
 subleq = Subleq()
 subleq.assemble(open(args[1], 'r').read())
 with open(args[2], 'w') as f:
 subleq.dump_triples(f)
 elif len(args) == 2 and args[0] == 'run':
 subleq = Subleq()
 with open(args[1], 'r') as f:
 subleq.load_triples(f)
 subleq.run()
 elif len(args) == 2 and args[0] == 'trace':
 subleq = Subleq()
 with open(args[1], 'r') as f:
 subleq.load_triples(f)
 subleq.run(trace=True)
 else:
 print('usage: subleq.py assemble in.subleqasm out.triples | run in.triples | trace in.triples')
 sys.exit(1)
if __name__ == '__main__':
 main(sys.argv[1:])

• Implementations