Subleq VM

print-x.subleq

6 7 3
7 -1 9
2 122 0
8 35 -7

subleq-dynamic.rb

# subleq VM
# this version allows dynamic memory allocation (expanding memory by accessing it)
# 208 bytes (smaller with no whitespace)
# uses loc -1 for ascii output
# see http://mazonka.com/subleq/
# pass commands to STDIN or as a filename argument
i=0;m = ARGF.read.split(/\s+/).map{|x|x.to_i}
while i>=0
  m.fill(0,m.length..m[i+1]) if m[i+1]>m.length
  m[i+1]>0 ? m[m[i+1]]-=m[m[i]] : print(m[m[i]].chr)
  i=(i > 0 ? m[m[i+1]] : 0) > 0 ? i+1 : m[i+2]
end

subleq-neat.rb

# subleq VM
# neat version
# uses loc -1 for ascii output
# see http://mazonka.com/subleq/
# pass commands to STDIN or as a filename argument

mem = ARGF.read.split(/\s+/).map{|x|x.to_i}
i=0
while i>=0
  mem[i+1] != -1 ? mem[mem[i+1]] -= mem[mem[i]] : print(mem[mem[i]].chr)
  if (i > 0 ? mem[mem[i+1]] : 0) > 0
    i+=1 
  else 
    i=mem[i+2]
  end
end

subleq.rb

# subleq VM
# 162 bytes (could be smaller without lines and tabs)
# uses loc -1 for ascii output
# see http://mazonka.com/subleq/
# pass commands to STDIN or as a filename argument

i,m = 0,ARGF.read.split(/\s+/).map{|x|x.to_i}
while i>=0
  m[i+1]!=-1 ? m[m[i+1]]-=m[m[i]] : print(m[m[i]].chr)
  i=(i > 0 ? m[m[i+1]] : 0) > 0 ? i+1 : m[i+2]
end

The test program only runs with dynamic allocation.