74 lines
1.7 KiB
Text
74 lines
1.7 KiB
Text
use fmt;
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use fs;
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use io;
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use os;
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export fn main() void = {
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if (len(os::args) != 2) {
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fmt::print("Please provide a parameter pointing to a brain**** file.\n")!;
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return;
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};
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let program = slurp(os::args[1])!;
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let tape: [30000]u8 = [0...];
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let tp: u16 = 0;
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defer free(program);
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let matches_k: []size = [];
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let matches_v: []size = [];
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defer free(matches_k);
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defer free(matches_v);
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for (let pp: size = 0; pp < len(program); pp += 1) {
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switch (program[pp]) {
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case '>' => tp += 1;
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case '<' => tp -= 1;
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case '+' => tape[tp] += 1;
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case '-' => tape[tp] -= 1;
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case '.' => io::write(os::stdout, tape[tp..tp+1])!;
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case ',' => io::read(os::stdin, tape[tp..tp+1])!;
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case '[' => if (tape[tp] == 0) pp = find_match(pp, program, matches_k, matches_v)!;
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case ']' => if (tape[tp] != 0) pp = find_match(pp, program, matches_k, matches_v)!;
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case => continue;
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};
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};
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};
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fn find_match(pos: size, program: []u8, matches_k: []size, matches_v: []size) (size | !void) = {
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for (let i: u16 = 0; i < len(matches_k); i += 1)
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if (pos == matches_k[i])
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return matches_v[i];
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let r = pos;
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switch (program[pos]) {
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case '[' => {
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r += 1;
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for (let level = 1; level > 0; r += 1) {
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switch (program[r]) {
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case '[' => level += 1;
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case ']' => level -= 1;
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case => continue;
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};
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};
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};
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case ']' => {
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r -= 1;
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for (let level = 1; level > 0; r -= 1) {
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switch (program[r]) {
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case ']' => level += 1;
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case '[' => level -= 1;
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case => continue;
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};
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};
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};
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case => return;
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};
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append(matches_k, pos)!;
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append(matches_v, r)!;
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return r;
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};
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fn slurp(filename: str) ([]u8 | fs::error | io::error) = {
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const file = os::open(filename)?;
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defer io::close(file)!;
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return io::drain(file)?;
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};
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