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https://github.com/zaphar/ucg.git
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625 lines
18 KiB
Rust
625 lines
18 KiB
Rust
// Copyright 2019 Jeremy Wall
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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pub mod pointer;
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pub mod scope;
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use pointer::OpPointer;
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use scope::Stack;
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#[derive(Debug, PartialEq, Clone)]
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pub enum Primitive {
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// Primitive Types
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Int(i64),
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Float(f64),
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Str(String),
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Bool(bool),
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Empty,
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}
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use Primitive::{Bool, Float, Int, Str};
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#[derive(Debug, PartialEq, Clone)]
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pub enum Composite {
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List(Vec<Value>),
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Tuple(Vec<(String, Value)>),
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}
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use Composite::{List, Tuple};
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#[derive(Debug, PartialEq, Clone)]
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pub struct Func {
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ptr: usize,
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bindings: Vec<String>,
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snapshot: Stack,
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}
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#[derive(Debug, PartialEq, Clone)]
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pub struct Module {
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ptr: usize,
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result_ptr: Option<usize>,
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flds: Vec<(String, Value)>,
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}
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#[derive(Debug, PartialEq, Clone)]
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pub enum Value {
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// Binding names.
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S(String),
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// Primitive Types
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P(Primitive),
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// Composite Types.
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C(Composite),
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// Program Pointer
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T(usize),
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// Function
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F(Func),
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// Module
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M(Module),
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}
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use Value::{C, F, M, P, S, T};
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#[derive(Debug, PartialEq, Clone)]
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pub enum Op {
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// Stack and Name manipulation.
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Bind, // Bind a Val to a name in the heap
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Pop, // Pop a Value off the value stack and discard it.
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// Math ops
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Add,
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Sub,
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Div,
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Mul,
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// Comparison Ops
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Equal,
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Gt,
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Lt,
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GtEq,
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LtEq,
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// Primitive Types ops
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Val(Primitive),
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// A bareword for use in bindings or lookups
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Sym(String),
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// Reference a binding on the heap
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DeRef(String),
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// Complex Type ops
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InitTuple,
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Field,
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InitList,
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Element,
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// Copy Operation
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Cp,
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// Control Flow
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Bang,
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Jump(i32),
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JumpIfTrue(i32),
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JumpIfFalse(i32),
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SelectJump(i32),
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// FIXME(jwall): Short circuiting operations
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// - And(usize)
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// - Or(usize)
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// Spacer operation, Does nothing.
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Noop,
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// Pending Computation
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InitThunk(i32), // Basically just used for module return expressions
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Module(usize),
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Func(usize),
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Return,
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// - Call
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FCall,
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// Runtime hooks
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// - Map,
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// - Filter,
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// - Reduce,
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// - Import,
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// - Out,
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// - Assert,
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// - Print,
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}
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#[derive(Debug)]
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pub struct Error {}
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pub struct VM<'a> {
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stack: Vec<Value>,
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symbols: Stack,
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ops: OpPointer<'a>,
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}
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impl<'a> VM<'a> {
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pub fn new(ops: &'a Vec<Op>) -> Self {
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Self {
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stack: Vec::new(),
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symbols: Stack::new(),
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ops: OpPointer::new(ops),
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}
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}
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pub fn to_scoped(&self, symbols: Stack) -> Self {
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Self {
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stack: Vec::new(),
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symbols: symbols,
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ops: self.ops.clone(),
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}
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}
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pub fn run(&mut self) -> Result<(), Error> {
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while self.ops.next().is_some() {
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let idx = self.ops.ptr.unwrap();
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match dbg!(self.ops.op()).unwrap() {
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Op::Val(p) => self.push(dbg!(P(p.clone())))?,
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Op::Sym(s) => self.push(S(s.clone()))?,
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Op::DeRef(s) => self.op_deref(s.clone())?,
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Op::Add => self.op_add()?,
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Op::Sub => self.op_sub()?,
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Op::Mul => self.op_mul()?,
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Op::Div => self.op_div()?,
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Op::Bind => self.op_bind()?,
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Op::Equal => self.op_equal()?,
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Op::Gt => self.op_gt()?,
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Op::Lt => self.op_lt()?,
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Op::GtEq => self.op_gteq()?,
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Op::LtEq => self.op_lteq()?,
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// Add a Composite list value to the stack
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Op::InitList => self.push(C(List(Vec::new())))?,
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// Add a composite tuple value to the stack
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Op::InitTuple => self.push(C(Tuple(Vec::new())))?,
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Op::Field => self.op_field()?,
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Op::Element => self.op_element()?,
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Op::Cp => self.op_copy()?,
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//TODO(jwall): Should this take a user provided message?
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Op::Bang => return dbg!(Err(Error {})),
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Op::InitThunk(jp) => self.op_thunk(idx, *jp)?,
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Op::Noop => {
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// Do nothing
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}
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Op::Jump(jp) => self.op_jump(*jp)?,
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Op::JumpIfTrue(jp) => self.op_jump_if_true(*jp)?,
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Op::JumpIfFalse(jp) => self.op_jump_if_false(*jp)?,
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Op::SelectJump(jp) => self.op_select_jump(*jp)?,
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Op::Module(mptr) => self.op_module(idx, *mptr)?,
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Op::Func(jptr) => self.op_func(idx, *jptr)?,
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Op::FCall => self.op_fcall()?,
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Op::Return => return Ok(()),
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Op::Pop => {
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self.pop()?;
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}
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};
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}
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Ok(())
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}
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fn op_deref(&mut self, name: String) -> Result<(), Error> {
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let val = dbg!(self.get_binding(&name)?.clone());
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self.push(val)
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}
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fn op_jump(&mut self, jp: i32) -> Result<(), Error> {
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self.ops.jump(
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self.ops
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.ptr
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.map(|v| (v as i32 + jp) as usize)
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.unwrap_or(jp as usize),
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)?;
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Ok(())
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}
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fn op_jump_if_true(&mut self, jp: i32) -> Result<(), Error> {
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if let P(Bool(cond)) = self.pop()? {
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if cond {
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self.op_jump(jp)?;
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}
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}
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Ok(())
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}
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fn op_jump_if_false(&mut self, jp: i32) -> Result<(), Error> {
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if let P(Bool(cond)) = self.pop()? {
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if !cond {
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self.op_jump(jp)?;
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}
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}
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Ok(())
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}
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fn op_select_jump(&mut self, jp: i32) -> Result<(), Error> {
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// pop field value off
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let field_name = dbg!(self.pop())?;
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// pop search value off
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let search = dbg!(self.pop())?;
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// compare them.
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if dbg!(field_name != search) {
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self.op_jump(dbg!(jp))?;
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self.push(dbg!(search))?;
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}
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dbg!(self.ops.ptr.unwrap());
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// if they aren't equal then push search value back on and jump
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Ok(())
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}
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fn op_module(&mut self, idx: usize, jptr: usize) -> Result<(), Error> {
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let (result_ptr, flds) = match self.pop()? {
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C(Tuple(flds)) => (None, flds),
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T(ptr) => {
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if let C(Tuple(flds)) = self.pop()? {
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(Some(ptr), flds)
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} else {
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return dbg!(Err(Error {}));
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}
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}
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_ => {
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return dbg!(Err(Error {}));
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}
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};
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self.push(M(Module {
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ptr: dbg!(idx),
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result_ptr: result_ptr,
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flds: dbg!(flds),
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}))?;
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self.ops.jump(dbg!(jptr))
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}
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fn op_func(&mut self, idx: usize, jptr: usize) -> Result<(), Error> {
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// get arity from stack
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let mut scope_snapshot = self.symbols.snapshot();
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scope_snapshot.push();
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scope_snapshot.to_open();
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eprintln!("Defining a new function");
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let mut bindings = Vec::new();
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// get imported symbols from stack
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if let C(List(elems)) = self.pop()? {
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for e in elems {
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if let S(sym) = e {
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bindings.push(sym);
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} else {
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return dbg!(Err(Error {}));
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}
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}
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} else {
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return dbg!(Err(Error {}));
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}
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eprintln!("Pushing function definition on stack");
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self.push(dbg!(F(Func {
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ptr: idx, // where the function starts.
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bindings: bindings,
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snapshot: scope_snapshot,
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})))?;
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eprintln!("Jumping to {} past the function body", jptr);
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self.ops.jump(jptr)
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}
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fn op_fcall(&mut self) -> Result<(), Error> {
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let f = self.pop()?;
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if let F(Func {
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ptr,
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bindings,
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snapshot,
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}) = f
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{
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// TODO(jwall): This is wasteful. We can do better.
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let mut vm = self.to_scoped(snapshot);
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// use the captured scope snapshot for the function.
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for nm in bindings {
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// now put each argument on our scope stack as a binding.
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let val = self.pop()?;
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vm.binding_push(nm, val)?;
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}
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// proceed to the function body
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vm.ops.jump(ptr)?;
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vm.run()?;
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self.push(vm.pop()?)?;
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} else {
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return dbg!(Err(Error {}));
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}
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Ok(())
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}
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fn op_thunk(&mut self, idx: usize, jp: i32) -> Result<(), Error> {
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self.push(dbg!(T(idx)))?;
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self.op_jump(jp)
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}
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fn op_equal(&mut self) -> Result<(), Error> {
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let left = self.pop()?;
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let right = self.pop()?;
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self.push(P(Bool(left == right)))?;
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Ok(())
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}
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fn op_gt(&mut self) -> Result<(), Error> {
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let left = self.pop()?;
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let right = self.pop()?;
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match (left, right) {
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(P(Int(i)), P(Int(ii))) => {
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self.push(P(Bool(i > ii)))?;
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}
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(P(Float(f)), P(Float(ff))) => {
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self.push(P(Bool(f > ff)))?;
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}
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_ => return Err(Error {}),
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}
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Ok(())
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}
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fn op_lt(&mut self) -> Result<(), Error> {
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let left = self.pop()?;
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let right = self.pop()?;
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match (left, right) {
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(P(Int(i)), P(Int(ii))) => {
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self.push(P(Bool(i < ii)))?;
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}
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(P(Float(f)), P(Float(ff))) => {
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self.push(P(Bool(f < ff)))?;
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}
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_ => return Err(Error {}),
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}
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Ok(())
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}
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fn op_lteq(&mut self) -> Result<(), Error> {
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let left = self.pop()?;
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let right = self.pop()?;
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match (left, right) {
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(P(Int(i)), P(Int(ii))) => {
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self.push(P(Bool(i <= ii)))?;
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}
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(P(Float(f)), P(Float(ff))) => {
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self.push(P(Bool(f <= ff)))?;
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}
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_ => return Err(Error {}),
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}
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Ok(())
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}
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fn op_gteq(&mut self) -> Result<(), Error> {
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let left = self.pop()?;
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let right = self.pop()?;
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match (left, right) {
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(P(Int(i)), P(Int(ii))) => {
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self.push(P(Bool(i >= ii)))?;
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}
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(P(Float(f)), P(Float(ff))) => {
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self.push(P(Bool(f >= ff)))?;
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}
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_ => return Err(Error {}),
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}
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Ok(())
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}
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fn op_add(&mut self) -> Result<(), Error> {
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// Adds the previous two items in the stack.
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let left = self.pop()?;
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let right = self.pop()?;
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// Then pushes the result onto the stack.
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self.push(P(self.add(left, right)?))?;
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Ok(())
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}
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fn op_sub(&mut self) -> Result<(), Error> {
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// Subtracts the previous two items in the stack.
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let left = self.pop()?;
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let right = self.pop()?;
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// Then pushes the result onto the stack.
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self.push(P(self.sub(left, right)?))?;
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Ok(())
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}
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fn op_mul(&mut self) -> Result<(), Error> {
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// Multiplies the previous two items in the stack.
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let left = self.pop()?;
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let right = self.pop()?;
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// Then pushes the result onto the stack.
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self.push(P(self.mul(left, right)?))?;
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Ok(())
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}
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fn op_div(&mut self) -> Result<(), Error> {
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// Divides the previous two items in the stack.
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let left = self.pop()?;
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let right = self.pop()?;
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// Then pushes the result onto the stack.
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self.push(P(self.div(left, right)?))?;
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Ok(())
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}
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fn op_bind(&mut self) -> Result<(), Error> {
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// pop val off stack.
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let val = dbg!(self.pop())?;
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// pop name off stack.
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let name = dbg!(self.pop())?;
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if let S(name) = name {
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self.binding_push(name, val)?;
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} else {
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return Err(Error {});
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}
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Ok(())
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}
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fn op_field(&mut self) -> Result<(), Error> {
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// Add a Composite field value to a tuple on the stack
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// get value from stack
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let val = self.pop()?;
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// get name from stack.
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let name = if let S(s) | P(Str(s)) = self.pop()? {
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s
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} else {
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return Err(Error {});
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};
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// get composite tuple from stack
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let tpl = self.pop()?;
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if let C(Tuple(mut flds)) = tpl {
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// add name and value to tuple
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self.merge_field_into_tuple(&mut flds, name, val)?;
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// place composite tuple back on stack
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self.push(C(Tuple(flds)))?;
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} else {
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return Err(Error {});
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};
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Ok(())
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}
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fn op_element(&mut self) -> Result<(), Error> {
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// get element from stack.
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let val = self.pop()?;
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// get next value. It should be a Composite list.
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let tpl = self.pop()?;
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if let C(List(mut elems)) = tpl {
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// add value to list
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elems.push(val);
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// Add that value to the list and put list back on stack.
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self.push(C(List(elems)))?;
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} else {
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return Err(Error {});
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};
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Ok(())
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}
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fn op_copy(&mut self) -> Result<(), Error> {
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// TODO Use Cow pointers for this?
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// get next value. It should be a Module.
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let tgt = self.pop()?;
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match tgt {
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C(Tuple(mut flds)) => {
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let overrides = self.pop()?;
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if let C(Tuple(oflds)) = overrides {
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for (name, val) in oflds {
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self.merge_field_into_tuple(&mut flds, name, val)?;
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}
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} else {
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return dbg!(Err(Error {}));
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}
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// Put the copy on the Stack
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self.push(C(Tuple(flds)))?;
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}
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M(Module {
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ptr,
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result_ptr,
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mut flds,
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}) => {
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let overrides = dbg!(self.pop()?);
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if let C(Tuple(oflds)) = overrides {
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for (name, val) in oflds {
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self.merge_field_into_tuple(&mut flds, name, val)?;
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}
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} else {
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return dbg!(Err(Error {}));
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}
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let mut vm = VM::new(self.ops.ops);
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vm.push(S("mod".to_owned()))?;
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vm.push(C(Tuple(flds)))?;
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vm.ops.jump(ptr)?;
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vm.run()?;
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let mut flds = Vec::new();
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if let Some(ptr) = dbg!(result_ptr) {
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vm.ops.jump(ptr)?;
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vm.run()?;
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self.push(vm.pop()?)?;
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} else {
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for sym in vm.symbols.symbol_list() {
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if sym != "mod" {
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flds.push((sym.clone(), vm.symbols.get(sym).unwrap().clone()));
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}
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}
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self.push(dbg!(C(Tuple(flds))))?;
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}
|
|
}
|
|
_ => {
|
|
return Err(Error {});
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
fn merge_field_into_tuple(
|
|
&self,
|
|
src_fields: &mut Vec<(String, Value)>,
|
|
name: String,
|
|
value: Value,
|
|
) -> Result<(), Error> {
|
|
for fld in src_fields.iter_mut() {
|
|
if fld.0 == name {
|
|
fld.1 = value;
|
|
return Ok(());
|
|
}
|
|
}
|
|
src_fields.push((name, value));
|
|
Ok(())
|
|
}
|
|
|
|
fn push(&mut self, p: Value) -> Result<(), Error> {
|
|
self.stack.push(p);
|
|
Ok(())
|
|
}
|
|
|
|
fn binding_push(&mut self, name: String, val: Value) -> Result<(), Error> {
|
|
if self.symbols.is_bound(&name) {
|
|
return Err(Error {});
|
|
}
|
|
self.symbols.add(name, val);
|
|
Ok(())
|
|
}
|
|
|
|
pub fn get_binding(&mut self, name: &str) -> Result<&Value, Error> {
|
|
match self.symbols.get(name) {
|
|
Some(v) => Ok(v),
|
|
None => Err(Error {}),
|
|
}
|
|
}
|
|
|
|
fn pop(&mut self) -> Result<Value, Error> {
|
|
match self.stack.pop() {
|
|
Some(v) => Ok(v),
|
|
None => Err(Error {}),
|
|
}
|
|
}
|
|
|
|
fn mul(&self, left: Value, right: Value) -> Result<Primitive, Error> {
|
|
Ok(match (left, right) {
|
|
(P(Int(i)), P(Int(ii))) => Int(i * ii),
|
|
(P(Float(f)), P(Float(ff))) => Float(f * ff),
|
|
_ => return Err(Error {}),
|
|
})
|
|
}
|
|
|
|
fn div(&self, left: Value, right: Value) -> Result<Primitive, Error> {
|
|
Ok(match (left, right) {
|
|
(P(Int(i)), P(Int(ii))) => Int(i / ii),
|
|
(P(Float(f)), P(Float(ff))) => Float(f / ff),
|
|
_ => return Err(Error {}),
|
|
})
|
|
}
|
|
|
|
fn sub(&self, left: Value, right: Value) -> Result<Primitive, Error> {
|
|
Ok(match (left, right) {
|
|
(P(Int(i)), Value::P(Int(ii))) => Int(i - ii),
|
|
(P(Float(f)), Value::P(Float(ff))) => Float(f - ff),
|
|
_ => return Err(Error {}),
|
|
})
|
|
}
|
|
|
|
fn add(&self, left: Value, right: Value) -> Result<Primitive, Error> {
|
|
Ok(match (left, right) {
|
|
(P(Int(i)), Value::P(Int(ii))) => Int(i + ii),
|
|
(P(Float(f)), Value::P(Float(ff))) => Float(f + ff),
|
|
(P(Str(s)), Value::P(Str(ss))) => {
|
|
let mut ns = String::new();
|
|
ns.push_str(&s);
|
|
ns.push_str(&ss);
|
|
Str(ns)
|
|
}
|
|
_ => return Err(Error {}),
|
|
})
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test;
|