parsing

bfi-rust/bf.b

@@ -1 +1,11 @@
-++++++++++[>+++++++++<-].
+++++++++++[>++++++++++<-]>>++++++++++>->>>>>>>>>>>>>>>>-->+++++++[->++
+++++++++<]>[->+>+>+>+<<<<]+++>>+++>>>++++++++[-<++++<++++<++++>>>]++++
++[-<++++<++++>>]>>-->++++++[->+++++++++++<]>[->+>+>+>+<<<<]+++++>>+>++
+++++>++++++>++++++++[-<++++<++++<++++>>>]++++++[-<+++<+++<+++>>>]>>-->
+---+[-<+]-<[+[->+]-<<->>>+>[-]++[-->++]-->+++[---++[--<++]---->>-<+>[+
++++[----<++++]--[>]++[-->++]--<]>++[--+[-<+]->>[-]+++++[---->++++]-->[
+->+<]>>[.>]++[-->++]]-->+++]---+[-<+]->>-[+>>>+[-<+]->>>++++++++++<<[-
+>+>-[>+>>]>[+[-<+>]>+>>]<<<<<<]>>[-]>>>++++++++++<[->-[>+>>]>[+[-<+>]>
++>>]<<<<<]>[-]>>[>++++++[-<++++++++>]<.<<+>+>[-]]<[<[->-<]++++++[->+++
++++++<]>.[-]]<<++++++[-<++++++++>]<.[-]<<[-<+>]+[-<+]->>]+[-]<<<.>>>+[
+-<+]-<<]

bfi-rust/src/main.rs

@@ -1,5 +1,5 @@
-use std::io::{stdin, Read};
 use std::{env, fs};
+use std::io::{Read, stdin};
 use std::time::SystemTime;
 
 fn main() {
@@ -92,3 +92,94 @@ fn interpret(pgm: Vec<char>) -> String {
 
     out
 }
+
+///
+/// # optimization time
+///
+/// first parse the bf so that it can be exectued faster
+/// most importantly: loop jumps should be immediate
+///
+mod o1 {
+    const MEM_SIZE: usize = 0xFFFF;
+
+    type Memory = [u8; MEM_SIZE];
+
+    ///
+    /// A single Statement, can be an instruction or a nestable loop
+    #[derive(Debug, PartialOrd, PartialEq)]
+    enum Statement {
+        Inc,
+        Dec,
+        R,
+        L,
+        Out,
+        In,
+        Loop(Vec<Statement>),
+    }
+
+
+    fn minify(code: String) -> String {
+        let allowed: Vec<char> = vec!['>', '<', '+', '-', '.', ',', '[', ']'];
+        code.chars().filter(|c| allowed.contains(c)).collect()
+    }
+
+    fn parse(chars: Vec<char>) -> Vec<Statement> {
+        let mut loop_stack = vec![vec![]];
+
+        for c in chars {
+            match c {
+                '+' => loop_stack.last_mut().unwrap().push(Statement::Inc),
+                '-' => loop_stack.last_mut().unwrap().push(Statement::Dec),
+                '>' => loop_stack.last_mut().unwrap().push(Statement::R),
+                '<' => loop_stack.last_mut().unwrap().push(Statement::L),
+                '.' => loop_stack.last_mut().unwrap().push(Statement::Out),
+                ',' => loop_stack.last_mut().unwrap().push(Statement::In),
+                '[' => loop_stack.push(vec![]),
+                ']' => {
+                    let statement = Statement::Loop(loop_stack.pop().unwrap());
+                    loop_stack.last_mut().unwrap().push(statement);
+                },
+                _ => ()
+            }
+        }
+
+        return loop_stack.pop().unwrap();
+    }
+
+    fn interpret_o1(pgm: Vec<Statement>) {
+
+    }
+
+
+    #[cfg(test)]
+    mod test {
+        use crate::o1::{parse, Statement::{self, Inc, Dec, R, L, In, Out, Loop}};
+
+        #[test]
+        fn parse_no_loop() {
+            let program = "+-<>,.";
+            let statements = vec![Inc, Dec, L, R, In, Out];
+            let result = parse(program.chars().collect());
+
+            assert_eq!(statements, result);
+        }
+
+        #[test]
+        fn parse_simple_loop() {
+            let program = "+[<<]-";
+            let statements = vec![Inc, Loop(vec![L, L]), Dec];
+            let result = parse(program.chars().collect());
+
+            assert_eq!(statements, result);
+        }
+
+        #[test]
+        fn parse_complex_loops() {
+            let program = ">[<[][<[<]>]>[>]]";
+            let statements = vec![R, Loop(vec![L, Loop(vec![]), Loop(vec![L, Loop(vec![L]), R]), R, Loop(vec![R])])];
+            let result = parse(program.chars().collect());
+
+            assert_eq!(statements, result);
+        }
+    }
+}