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-rw-r--r--src/forth/interp.rs532
1 files changed, 0 insertions, 532 deletions
diff --git a/src/forth/interp.rs b/src/forth/interp.rs
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index 512c022..0000000
--- a/src/forth/interp.rs
+++ /dev/null
@@ -1,532 +0,0 @@
-use log::debug;
-
-use std::ops::Index;
-
-#[derive(Clone, Debug, PartialEq)]
-pub enum OpCode {
- Num(i32),
- Str(usize, usize),
- Call(usize),
- TCall(usize), // tail call, really just ‘jmp’, but named to indicate desired usage.
- If(usize, Option<usize>), // true word index, optional false word index.
- TIf(usize, Option<usize>), // tail version
- Add,
- Sub,
- Mul,
- Div,
- Dup,
- Drop,
- EQ,
- GT,
- GTE,
- LT,
- LTE,
- // todo: maybe get rid of ret? it's only used in word definitions,
- // which are bounded, so running of the end can be treated as an
- // implicit ‘ret’.
- Ret,
-}
-
-#[derive(Clone, Debug)]
-pub struct ByteCode(pub Vec<OpCode>);
-impl std::ops::Deref for ByteCode {
- type Target = Vec<OpCode>;
- fn deref(&self) -> &Self::Target {
- &self.0
- }
-}
-
-impl ByteCode {
- pub fn len(&self) -> usize {
- self.0.len()
- }
-}
-
-impl Index<usize> for ByteCode {
- type Output = OpCode;
-
- fn index(&self, index: usize) -> &Self::Output {
- &self.0[index]
- }
-}
-
-#[derive(Debug, Copy, Clone, PartialEq)]
-pub struct InstructionPointer {
- pub word: usize,
- pub offset: usize,
-}
-
-impl InstructionPointer {
- pub fn new() -> Self {
- Self {
- word: 0,
- offset: 0,
- }
- }
-}
-
-#[derive(Debug)]
-pub struct DataStack(pub Vec<i32>);
-
-#[derive(Debug)]
-pub struct CallStack(pub Vec<InstructionPointer>);
-
-#[derive(Clone, Debug)]
-pub struct WordList(pub Vec<ByteCode>);
-impl std::ops::Deref for WordList {
- type Target = Vec<ByteCode>;
- fn deref(&self) -> &Self::Target {
- &self.0
- }
-}
-
-#[derive(Debug)]
-pub struct Interp {
- // todo: don't be pub, probably
- pub stack: DataStack,
- pub callstack: CallStack,
- pub wordlist: WordList,
- pub ip: InstructionPointer,
-}
-
-#[derive(Debug)]
-pub enum RuntimeError {
- StackUnderflow,
-}
-
-impl Interp {
- pub fn new(wordlist: WordList) -> Self {
- Self {
- stack: DataStack(Vec::new()),
- callstack: CallStack(Vec::new()),
- ip: InstructionPointer::new(),
- wordlist,
- }
- }
-
- pub fn jmp(&mut self, word: usize) {
- self.ip.word = word;
- self.ip.offset = 0;
- }
-
- pub fn call(&mut self, word: usize) {
- self.callstack.0.push(self.ip);
- self.jmp(word);
- }
-
- // bool is still_running
- pub fn tick(&mut self) -> Result<bool, RuntimeError> {
- let bc = &self.wordlist.0[self.ip.word];
- match bc[self.ip.offset] {
- OpCode::Num(n) => self.stack.0.push(n),
- OpCode::Str(start, end) => debug!("got str: {} to {}", start, end),
- OpCode::Add => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- self.stack.0.push(n2 + n1);
- },
- OpCode::Sub => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- self.stack.0.push(n2 - n1);
- },
- OpCode::Mul => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- self.stack.0.push(n2 * n1);
- },
- OpCode::Div => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- self.stack.0.push(n2 / n1);
- },
- OpCode::Dup => {
- let n = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- self.stack.0.push(n);
- self.stack.0.push(n);
- },
- OpCode::Drop => {
- self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- },
- OpCode::EQ => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let v = if n2 == n1 { -1 } else { 0 };
- self.stack.0.push(v);
- },
- OpCode::GT => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let v = if n2 > n1 { -1 } else { 0 };
- self.stack.0.push(v);
- },
- OpCode::GTE => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let v = if n2 >= n1 { -1 } else { 0 };
- self.stack.0.push(v);
- },
- OpCode::LT => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let v = if n2 < n1 { -1 } else { 0 };
- self.stack.0.push(v);
- },
- OpCode::LTE => {
- let n1 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let n2 = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- let v = if n2 <= n1 { -1 } else { 0 };
- self.stack.0.push(v);
- },
- OpCode::Ret => {
- self.ip = self.callstack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- },
- OpCode::Call(i) => {
- self.call(i);
- // skip the offset increment
- return Ok(true)
- },
- OpCode::TCall(i) => {
- self.jmp(i);
- // skip the offset increment
- return Ok(true)
- },
- OpCode::If(true_clause, false_clause) => {
- let flag = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- if flag != 0 {
- self.call(true_clause);
- return Ok(true)
- } else if let Some(false_clause) = false_clause {
- self.call(false_clause);
- return Ok(true)
- }
- },
- OpCode::TIf(true_clause, false_clause) => {
- let flag = self.stack.0.pop().ok_or(RuntimeError::StackUnderflow)?;
- if flag != 0 {
- self.jmp(true_clause);
- return Ok(true)
- } else if let Some(false_clause) = false_clause {
- self.jmp(false_clause);
- return Ok(true)
- }
- },
- }
- self.ip.offset += 1;
- Ok(self.ip.offset < self.wordlist.0[self.ip.word].len())
- }
-
- pub fn run(&mut self) -> Result<usize, RuntimeError> {
- let mut count = 0;
- while self.tick()? { count += 1 }
- Ok(count)
- }
-}
-
-#[cfg(test)]
-mod tests {
- use super::*;
- use super::OpCode;
-
- #[test]
- fn simple_ticks() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Num(2), OpCode::Num(3), OpCode::Add]));
- let mut interp = Interp::new(wordlist);
- assert_eq!(interp.tick()?, true, "first arg running");
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 1);
- assert_eq!(interp.stack.0.len(), 1);
- assert_eq!(interp.stack.0[0], 2, "first argument");
- assert_eq!(interp.tick()?, true, "second arg running");
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 2);
- assert_eq!(interp.stack.0.len(), 2);
- assert_eq!(interp.stack.0[1], 3, "second argument");
- assert_eq!(interp.tick()?, false, "stopped after addition");
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 3);
- assert_eq!(interp.stack.0.len(), 1);
- assert_eq!(interp.stack.0[0], 5, "result of addition");
-
- Ok(())
- }
-
- #[test]
- fn custom_word() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![
- OpCode::Num(2), OpCode::Num(3), OpCode::Call(1), OpCode::Num(-2), OpCode::Add,
- OpCode::Sub, OpCode::Ret,
- ]));
- let mut interp = Interp::new(wordlist);
- // "sub" definition
- interp.wordlist.0.push(ByteCode(vec![
- OpCode::Sub, OpCode::Ret,
- ]));
-
- interp.tick()?;
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 1);
- assert_eq!(interp.stack.0.len(), 1);
- assert_eq!(interp.stack.0[0], 2, "first argument");
- interp.tick()?;
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 2);
- assert_eq!(interp.stack.0.len(), 2);
- assert_eq!(interp.stack.0[1], 3, "second argument");
-
- interp.tick()?; // call sub
- assert_eq!(interp.ip.word, 1);
- assert_eq!(interp.ip.offset, 0);
- assert_eq!(interp.stack.0.len(), 2);
-
- interp.tick()?; // -
- assert_eq!(interp.ip.word, 1);
- assert_eq!(interp.ip.offset, 1);
- assert_eq!(interp.stack.0.len(), 1);
-
- interp.tick()?; // ret
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 3);
- assert_eq!(interp.stack.0.len(), 1);
- assert_eq!(interp.stack.0[0], -1, "result of sub word");
-
- interp.tick()?; // 2
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 4);
- assert_eq!(interp.stack.0.len(), 2);
- assert_eq!(interp.stack.0[1], -2, "post sub arg");
-
- interp.tick()?; // -
- assert_eq!(interp.ip.word, 0);
- assert_eq!(interp.ip.offset, 5);
- assert_eq!(interp.stack.0.len(), 1);
- assert_eq!(interp.stack.0[0], -3, "add opcode result");
-
- Ok(())
- }
-
- #[test]
- fn tail_call() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Call(1)]));
- wordlist.0.push(ByteCode(vec![OpCode::TCall(2), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?; // call
- assert_eq!(interp.callstack.0.len(), 1, "callstack after call");
- interp.tick()?; // tcall
- assert_eq!(interp.callstack.0.len(), 1, "callstack after tcall");
- interp.tick()?; // ret
- assert_eq!(interp.callstack.0.len(), 0, "callstack after ret");
- Ok(())
- }
-
- #[test]
- fn if_then_true() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Num(-1), OpCode::If(1, None), OpCode::Num(0)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push -1 stack len");
- assert_eq!(interp.stack.0[0], -1, "push -1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "if stack ");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 1 stack len");
- assert_eq!(interp.stack.0[0], 1, "push 1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "ret stack len");
- assert_eq!(interp.stack.0[0], 1, "ret stack val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 2, "push 0 stack len");
- assert_eq!(interp.stack.0[1], 0, "push 0 stack val");
-
- Ok(())
- }
-
- #[test]
- fn if_then_false() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Num(0), OpCode::If(1, None), OpCode::Num(-1)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 0 stack len");
- assert_eq!(interp.stack.0[0], 0, "push 0 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "if stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push -1 stack len");
- assert_eq!(interp.stack.0[0], -1, "push -1 val");
-
- Ok(())
- }
-
- #[test]
- fn if_else_then_true() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Num(-1), OpCode::If(1, Some(2)), OpCode::Num(-2)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(2), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push -1 stack len");
- assert_eq!(interp.stack.0[0], -1, "push -1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "if stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 1 stack len");
- assert_eq!(interp.stack.0[0], 1, "push 1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "ret stack len");
- assert_eq!(interp.stack.0[0], 1, "ret val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 2, "push -2 stack len");
- assert_eq!(interp.stack.0[1], -2, "push -2 val");
-
- Ok(())
- }
-
- #[test]
- fn if_else_then_false() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Num(0), OpCode::If(1, Some(2)), OpCode::Num(-2)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(2), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 0 stack len");
- assert_eq!(interp.stack.0[0], 0, "push 0 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "if");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 2 stack len");
- assert_eq!(interp.stack.0[0], 2, "push 2 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "ret");
- assert_eq!(interp.stack.0[0], 2, "ret");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 2, "push -2 stack len");
- assert_eq!(interp.stack.0[1], -2, "push -2 val");
-
- Ok(())
- }
-
- #[test]
- fn tail_if_then_true() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Call(1), OpCode::Num(0)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(-1), OpCode::TIf(2, None), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "call(1) stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push -1 stack len");
- assert_eq!(interp.stack.0[0], -1, "push -1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "tif stack ");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 1 stack len");
- assert_eq!(interp.stack.0[0], 1, "push 1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "ret stack len");
- assert_eq!(interp.stack.0[0], 1, "ret stack val");
- interp.tick()?; // no ret on wordlist[1] since it's ‘tif’
- assert_eq!(interp.stack.0.len(), 2, "push 0 stack len");
- assert_eq!(interp.stack.0[1], 0, "push 0 stack val");
-
- Ok(())
- }
-
- #[test]
- fn tail_if_then_false() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Call(1), OpCode::Num(0)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(0), OpCode::TIf(2, None), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "call(1) stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 0 stack len");
- assert_eq!(interp.stack.0[0], 0, "push 0 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "tif stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "ret stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 0 stack len");
- assert_eq!(interp.stack.0[0], 0, "push 0 val");
-
- Ok(())
- }
-
- #[test]
- fn tail_if_else_then_true() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Call(1), OpCode::Num(-2)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(-1), OpCode::TIf(2, Some(3)), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(2), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "call(1) stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push -1 stack len");
- assert_eq!(interp.stack.0[0], -1, "push -1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "tif stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 1 stack len");
- assert_eq!(interp.stack.0[0], 1, "push 1 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "ret stack len");
- assert_eq!(interp.stack.0[0], 1, "ret val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 2, "push -2 stack len");
- assert_eq!(interp.stack.0[1], -2, "push -2 val");
-
- Ok(())
- }
-
- #[test]
- fn tail_if_else_then_false() -> Result<(), RuntimeError> {
- let mut wordlist = WordList(vec![]);
- wordlist.0.push(ByteCode(vec![OpCode::Call(1), OpCode::Num(-2)]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(0), OpCode::TIf(2, Some(3)), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(1), OpCode::Ret]));
- wordlist.0.push(ByteCode(vec![OpCode::Num(2), OpCode::Ret]));
- let mut interp = Interp::new(wordlist);
-
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "call(1) stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 0 stack len");
- assert_eq!(interp.stack.0[0], 0, "push 0 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 0, "tif stack len");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "push 2 stack len");
- assert_eq!(interp.stack.0[0], 2, "push 2 val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 1, "ret stack len");
- assert_eq!(interp.stack.0[0], 2, "ret val");
- interp.tick()?;
- assert_eq!(interp.stack.0.len(), 2, "push -2 stack len");
- assert_eq!(interp.stack.0[1], -2, "push -2 val");
-
- Ok(())
- }
-}
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