ft: initial impl

.gitignore

@@ -0,0 +1 @@
+/target

Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "brainfuck-rs"
+version = "0.1.0"

Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "brainfuck-rs"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

src/main.rs

@@ -0,0 +1,69 @@
+use std::io::{self, Read};
+
+fn interpret(code: &str) {
+    let mut memory = [0 as u8; 10_000];
+    let mut head = 0 as usize;
+    let mut pc = 0 as usize;
+    let mut loop_stack = Vec::new();
+
+    let code_bytes = code.as_bytes();
+    while pc < code.len() {
+        match code_bytes[pc] as char {
+            '>' => head += 1,
+            '<' => head -= 1,
+            '+' => memory[head] += 1,
+            '-' => memory[head] -= 1,
+            '.' => println!("{}", memory[head]),
+            ',' => {
+                let mut input_buf = [0u8; 1];
+                if io::stdin().read_exact(&mut input_buf).is_ok() {
+                    memory[head] = input_buf[0];
+                }
+            }
+            '[' => {
+                // loop start
+                if memory[pc] == 0 {
+                    let mut count_brackets = 1;
+
+                    // find nested brackets
+                    while count_brackets > 0 {
+                        pc += 1;
+                        if pc >= code_bytes.len() {
+                            panic!("Missing closing loop!");
+                        }
+                        match code_bytes[pc] as char {
+                            // closing current loop
+                            ']' => count_brackets -= 1,
+                            // nested bracket
+                            '[' => count_brackets += 1,
+                            // ignore rest
+                            _ => {}
+                        }
+                    }
+                } else {
+                    // save pc to jump back to
+                    loop_stack.push(pc);
+                }
+            }
+            ']' => {
+                // loop terminator
+                if memory[pc] != 0 {
+                    if let Some(start_pc) = loop_stack.last() {
+                        pc = *start_pc;
+                    }
+                } else {
+                    // loop done, continue normally
+                    loop_stack.pop();
+                }
+            }
+            _ => panic!("Invalid instruction"),
+        }
+        pc += 1;
+    }
+}
+
+fn main() {
+    let code = "+++++++++[>++++++++<-]>.";
+    let hello_world = "++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.";
+    interpret(hello_world);
+}