From 096d8d00bc9f7498c60a583630b0eab1c9ed41a0 Mon Sep 17 00:00:00 2001
From: Scott Richmond <kredati@users.noreply.github.com>
Date: Sun, 15 Dec 2024 23:50:12 -0500
Subject: [PATCH] add untracked from opening bytecode branch

---
 src/main.rs | 68 +++++++++++++++++++++++++++++++++++++++++
 src/vm.rs   | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 155 insertions(+)
 create mode 100644 src/main.rs
 create mode 100644 src/vm.rs

diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..f38488b
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,68 @@
+use chumsky::{input::Stream, prelude::*};
+
+mod spans;
+
+mod lexer;
+use crate::lexer::lexer;
+
+mod parser;
+use crate::parser::parser;
+
+mod validator;
+
+mod compiler;
+use crate::compiler::Chunk;
+
+mod value;
+
+mod vm;
+use vm::Vm;
+
+pub fn run(src: &'static str) {
+    let (tokens, lex_errs) = lexer().parse(src).into_output_errors();
+    if !lex_errs.is_empty() {
+        println!("{:?}", lex_errs);
+        return;
+    }
+
+    let tokens = tokens.unwrap();
+
+    let (parse_result, parse_errors) = parser()
+        .parse(Stream::from_iter(tokens).map((0..src.len()).into(), |(t, s)| (t, s)))
+        .into_output_errors();
+    if !parse_errors.is_empty() {
+        println!("{:?}", parse_errors);
+        return;
+    }
+
+    let parsed = parse_result.unwrap();
+
+    let mut chunk = Chunk::new(&parsed, "test", src);
+    chunk.compile();
+    chunk.disassemble();
+
+    let mut vm = Vm::new(&chunk);
+    let result = vm.interpret();
+    let output = match result {
+        Ok(val) => val.show(&chunk),
+        Err(panic) => format!("{:?}", panic),
+    };
+    println!("{output}");
+}
+
+pub fn main() {
+    let src = "
+if false
+    then {
+        :foo
+        :bar
+        :baz
+    }
+    else {
+        1
+        2
+        3
+    }
+    ";
+    run(src);
+}
diff --git a/src/vm.rs b/src/vm.rs
new file mode 100644
index 0000000..33c4f6c
--- /dev/null
+++ b/src/vm.rs
@@ -0,0 +1,87 @@
+use crate::compiler::{Chunk, Op};
+use crate::parser::Ast;
+use crate::spans::Spanned;
+use crate::value::Value;
+use chumsky::prelude::SimpleSpan;
+use num_traits::FromPrimitive;
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Panic {
+    pub input: &'static str,
+    pub src: &'static str,
+    pub msg: String,
+    pub span: SimpleSpan,
+    pub trace: Vec<Trace>,
+    pub extra: String,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Trace {
+    pub callee: Spanned<Ast>,
+    pub caller: Spanned<Ast>,
+    pub function: Value,
+    pub arguments: Value,
+    pub input: &'static str,
+    pub src: &'static str,
+}
+
+pub struct Vm<'a> {
+    pub stack: Vec<Value>,
+    pub chunk: &'a Chunk<'a>,
+    pub ip: usize,
+    pub bindings: Vec<(u8, usize)>,
+}
+
+impl<'a> Vm<'a> {
+    pub fn new(chunk: &'a Chunk) -> Vm<'a> {
+        Vm {
+            chunk,
+            stack: vec![],
+            ip: 0,
+            bindings: vec![],
+        }
+    }
+
+    pub fn push(&mut self, value: Value) {
+        self.stack.push(value);
+    }
+
+    pub fn pop(&mut self) -> Value {
+        self.stack.pop().unwrap()
+    }
+
+    pub fn interpret(&mut self) -> Result<Value, Panic> {
+        let byte = self.chunk.bytecode[self.ip];
+        let op = Op::from_u8(byte).unwrap();
+        use Op::*;
+        match op {
+            Return => Ok(self.stack.pop().unwrap()),
+            Constant => {
+                let const_idx = self.chunk.bytecode[self.ip + 1];
+                let value = self.chunk.constants[const_idx as usize].clone();
+                self.push(value);
+                self.ip += 2;
+                self.interpret()
+            }
+            Jump => {
+                let jump_len = self.chunk.bytecode[self.ip + 1];
+                self.ip += jump_len as usize;
+                self.interpret()
+            }
+            JumpIfFalse => {
+                let jump_len = self.chunk.bytecode[self.ip + 1];
+                let cond = self.stack.pop().unwrap();
+                match cond {
+                    Value::Nil | Value::False => {
+                        self.ip += jump_len as usize + 2;
+                        self.interpret()
+                    }
+                    _ => {
+                        self.ip += 2;
+                        self.interpret()
+                    }
+                }
+            }
+        }
+    }
+}