inital commit

.gitignore

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+/target
+.idea
+*.iml

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "m8ni-rs"
+version = "0.1.0"

Cargo.toml

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+[package]
+name = "m8ni-rs"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

src/main.rs

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+enum Stmt {
+    Inc(usize),
+    Dec(usize),
+    IsZero(usize, usize),
+    Jump(usize),
+    Stop
+}
+
+fn main() {
+    let filename = match std::env::args().skip(1).next() {
+        Some(name) => name,
+        None => eprintln!("error: no file provided.\nUsage: <filename>"),
+    };
+
+    let program = std::fs::read_to_string(filename).unwrap();
+    let statements = parse(&program);
+}
+
+fn parse(text: &str) -> Result<Vec<Stmt>, String> {
+    text.lines().map(parse_line).collect()
+}
+
+
+fn parse_line(line: &str) -> Result<Stmt, String> {
+    const NO_REGISTER: fn() -> String = || "No register".to_string();
+    const NO_LINE_NUMBER: fn() -> String = || "No line number".to_string();
+    const EMPTY_LINE: fn() -> String = || "Empty line not allowed".to_string();
+
+
+    let mut iter = line.split_ascii_whitespace();
+    let first = iter.next().ok_or_else(EMPTY_LINE)?;
+
+    Ok(match first {
+        "INC" => {
+            let register = iter.next().ok_or_else(NO_REGISTER)?.parse()?;
+            Stmt::Inc(register)
+        }
+        "DEC" => {
+            let register = iter.next().ok_or_else(NO_REGISTER)?.parse()?;
+            Stmt::Dec(register)
+        }
+        "IS_ZERO" => {
+            let register = iter.next().ok_or_else(NO_REGISTER)?.parse()?;
+            let line_number = iter.next().ok_or_else(NO_LINE_NUMBER)?.parse()?;
+            Stmt::IsZero(register, line_number)
+        }
+        "JUMP" => {
+            let line_number = iter.next().ok_or_else(NO_LINE_NUMBER)?.parse()?;
+            Stmt::Jump(line_number)
+        }
+        "STOP" => Stmt::Stop,
+        stmt => return Err(format!("Illegal instruction: '{}'", stmt)),
+    })
+}

test.m8

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+INC 1
+INC 1
+INC 1
+INC 2
+INC 2
+IS_ZERO 1 22
+DEC 1
+IS_ZERO 2 13
+INC 4
+INC 5
+DEC 2
+JUMP 8
+IS_ZERO 4 17
+INC 3
+DEC 4
+JUMP 13
+IS_ZERO 5 21
+INC 2
+DEC 5
+JUMP 17
+JUMP 6
+STOP