!4warning

!4warning logo (Brainloller prog)

!4warning is a semi-serious output-only esolang. The name is a reference to xkcd: Random Number that evaluates against a Varnier scale.

Varnier scale

The Varnier scale is used as a ruler and can be rendered in graphing software. K describes a set of relations on x and y.

framesless

sin(10πx)>0
1<=y<=2
0<=x<=1
sin(12πx)<0
0<=y<=1
0<=x<=1
sin(10πx)=0
sin(11πx)=0
0<=y<=2
0<x<1

constant K

The field which is measured by the ruler can be described as the constant K.

K=

9452238590691318544677168576033200183352173863084085276275318211522354628763231360594706925388931138237215903222640767476400096069360530679935418459808368481610046763719747994227425913987337684765737036791110892391349802789451832819115487656320269576779073664600607318227318393653996155130791134302835878212423809302964077062823416265983444183318323940373872544663585781871588799140913348455312641602507741670812876131572546595553483686993258289946963100336958037351963177619919832712526811720379511912110879890167484262879803610293602475520

put

To perform the principal function (print):

1. !4warning compares a portable bitmap file with a P1 magic header against K.
2. If k = K print 4.
3. else: intervals = abs(k - K) // 17
4. print(chr(intervals % 128))

You could print any other ascii by evaluating the set of files given here.

interpreter

import sys

K = int(
 "94522385906913185446771685760332001833521738630840852762753182115223546287"
 "63231360594706925388931138237215903222640767476400096069360530679935418459"
 "80836848161004676371974799422742591398733768476573703679111089239134980278"
 "94518328191154876563202695767790736646006073182273183936539961551307911343"
 "02835878212423809302964077062823416265983444183318323940373872544663585781"
 "87158879914091334845531264160250774167081287613157254659555348368699325828"
 "99469631003369580373519631776199198327125268117203795119121108798901674842"
 "62879803610293602475520")

W, H = 106, 17

def read_pbm(data: bytes):
    """Parse P1 (ascii) or P4 (raw) PBM. Returns list of rows of 0/1."""
    if data[:2] == b'P1':
        toks = data[2:].split()
        w, h = int(toks[0]), int(toks[1])
        bits = ''.join(t.decode() for t in toks[2:])
        px = [int(c) for c in bits if c in '01']
        if len(px) < w*h:
            raise ValueError(f"P1 data too short: {len(px)} < {w*h}")
        return [px[r*w:(r+1)*w] for r in range(h)]
    if data[:2] == b'P4':
        # header: P4 <ws> w <ws> h <single ws> raw rows, each padded to a byte
        i, fields = 2, []
        while len(fields) < 2:
            while data[i] in b' \t\r\n': i += 1
            j = i
            while data[j] not in b' \t\r\n': j += 1
            fields.append(int(data[i:j])); i = j
        i += 1                      # single whitespace before raster
        w, h = fields
        rb = (w + 7)//8
        rows = []
        for r in range(h):
            chunk = data[i + r*rb : i + (r+1)*rb]
            row = []
            for c in range(w):
                row.append((chunk[c >> 3] >> (7 - (c & 7))) & 1)
            rows.append(row)
        return rows
    raise ValueError("not a P1/P4 PBM")

def tupper_k(rows):
    h = len(rows); w = len(rows[0])
    if h != H:
        raise ValueError(f"bitmap must be {H} rows tall, got {h}")
    if w > W:
        raise ValueError(f"bitmap wider than {W} columns ({w})")
    # narrower images sit at the left of the 106-column frame; rest is blank
    n = 0
    for r in range(h):
        for c in range(w):
            if rows[r][c]:
                x, y = (W - 1) - c, (H - 1) - r
                n |= 1 << (17*x + y)
    return 17 * n

def main(argv):
    data = open(argv[1], 'rb').read() if len(argv) > 1 else sys.stdin.buffer.read()
    k = tupper_k(read_pbm(data))
    if k == K:
        print(4)
    else:
        intervals = abs(k - K) // 17
        print(chr(intervals % 128))

if __name__ == '__main__':
    main(sys.argv)

See Also

Pierre Vernier