commit 1da2ac74d4af988667ad6e0fd214e53041427947
Author: mehbark <terezi@pyrope.net>
Date:   Mon Jun 24 13:23:11 2024 -0400

    brainf working!

diff --git a/bf.zig b/bf.zig
new file mode 100644
index 0000000..99aad46
--- /dev/null
+++ b/bf.zig
@@ -0,0 +1,82 @@
+//brainf
+const std = @import("std");
+const io = std.io;
+const fs = std.fs;
+const process = std.process;
+
+pub fn main() !void {
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    var allocator = arena.allocator();
+    defer arena.deinit();
+
+    var out = io.getStdOut().writer();
+    var in = io.getStdIn().reader();
+
+    var args = process.args();
+    defer args.deinit();
+    _ = args.skip();
+
+    const prog_path = args.next() orelse {
+        try io.getStdErr().writer().writeAll("i need a program path :(\n");
+        process.exit(1);
+    };
+
+    var prog_file = try fs.cwd().openFile(prog_path, .{});
+    const prog_unfiltered = try prog_file.readToEndAlloc(allocator, 1 << 24);
+    var prog = try allocator.alloc(u8, prog_unfiltered.len);
+    var prog_len: u32 = 0;
+    for (prog_unfiltered) |c| {
+        if (c == '+' or c == '-' or c == '>' or c == '<' or c == '[' or c == ']' or c == '.' or c == ',') {
+            prog[prog_len] = c;
+            prog_len += 1;
+        }
+    }
+
+    var mem = try allocator.alloc(u8, 1 << 16);
+    for (mem) |*m| {
+        m.* = 0;
+    }
+    var mp: u16 = 0;
+    var ip: u32 = 0;
+
+    while (ip < prog_len) {
+        switch (prog[ip]) {
+            '+' => mem[mp] +%= 1,
+            '-' => mem[mp] -%= 1,
+            '>' => mp +%= 1,
+            '<' => mp -%= 1,
+            '[' => {
+                if (mem[mp] == 0) {
+                    var depth: i16 = 1;
+                    ip += 1;
+                    while (depth > 0) : (ip += 1) {
+                        depth += switch (prog[ip]) {
+                            ']' => -1,
+                            '[' => 1,
+                            else => 0,
+                        };
+                    }
+                    ip -= 1;
+                }
+            },
+            ']' => {
+                if (mem[mp] != 0) {
+                    var depth: i16 = 1;
+                    ip -= 1;
+                    while (depth > 0) : (ip -= 1) {
+                        depth += switch (prog[ip]) {
+                            '[' => -1,
+                            ']' => 1,
+                            else => 0,
+                        };
+                    }
+                    ip += 1;
+                }
+            },
+            '.' => try out.writeByte(mem[mp]),
+            ',' => mem[mp] = in.readByte() catch 0,
+            else => unreachable,
+        }
+        ip += 1;
+    }
+}