"BF to BF*" compiler

gistfile1.txt

R = lambda d: -d*'<' if d<0 else d*'>'
L = lambda d: R(-d)
w0 = '{-}'
w1 = '{-}+'
bcopy = lambda dtmp, ddst: (
    R(dtmp)+w0+R(ddst-dtmp)+w0+L(ddst)
     +'+{'+R(dtmp)+'+'+R(ddst-dtmp)+'+'+L(ddst)+'-}'
     + '-'+R(dtmp)+'{'+L(dtmp)+'+'+R(dtmp)+'-}'
     + R(ddst-dtmp)+'-' )

def depth(p):
    l = m = 0
    for c in p:
        l += c=='['
        l -= c==']'
        m = max(m,l)
    return m

# returns (start, stride, program)
# begin at 0-indexed cell start and read every stride'th cell to find final tape values

def assemble(p):
    lmax = depth(p)
    k = 9 + lmax
    layout = dict(zip(range(lmax,-1,-1)+list('aqtxbcde'),range(k)))
    dif = lambda a,b: layout[b]-layout[a]
    mov = lambda a,b: R(dif(a,b))

    inc = lambda c: lambda l:(
        mov('x',l) +
        bcopy(dif(l,'a'),dif(l,'q')) +
        mov('q','a') +
        '{>}>' +
        c +
        '<{<}' +
        mov('a','t') +
        w0 +
        mov('t','x')
    )
    
    bra = lambda l: (
        mov('x',l) +
        w0 +
        mov(l,'b') +
        '{' +
        '>>>>{<}<<<'
    )

    qet = lambda l: (
        mov('x',l-1) +
        bcopy(dif(l-1,'a'),dif(l-1,l)) +
        bcopy(dif(l,'a'),dif(l,'c')) +
        mov('c','d') +
        '{<}<' +
        '}' +
        '>>>>{<}<<<'
    )
    
    move = lambda d: lambda l: (
        mov('x',0) +
        ''.join(bcopy(dif(i,'a'),d*k) + L(d*k+1) for i in range(l+1)) +
        R(d*k + dif(l,'e') + 1) +
        w1 +
        mov('e','q') +
        w0 +
        R(-d*k + dif('q',l)) +
        bcopy(dif(l,'a'),dif(l,'q')) +
        L(d*k) +
        '{' +
        R(d*k) +
        '}' +
        mov('q','x')
    )
        
        
    inst = { '+': inc('+'),
             '-': inc('-'),
             '<': move(-1),
             '>': move(1),
             '[': bra,
             ']': qet 
           }
    pad = 2*k
    out = (
        R(pad) +
        mov(lmax,0) +
        w1 +
        mov(0,'e') +
        w1 +
        mov('e','x')
    )
    
    l = 0
    for c in p:
        l += c=='['
        out += inst.get(c,lambda _:'')(l)
        l -= c==']'
    return 4+pad+lmax, k, out