interpreter: rewrite interpreter

- Remove interpreter struct
- Replace with `Interpret` trait
- This separates concerns dramatically! Yay!
- Implement block scoping via `Frame` abstraction
  - TODO: is this the right abstraction?
  - TODO: Modules??
  - TODO: What environment should be passed into a function call?
ast:
- rename Name.name to Name.symbol (name.name.name.name.name.name.name is very readable, yes yes)
This commit is contained in:
John 2024-01-05 17:48:19 -06:00
parent 9eafae0757
commit d387e4dfd7
5 changed files with 425 additions and 578 deletions

View File

@ -69,7 +69,7 @@ pub mod program {
use conlang::{
ast::preamble::{expression::Expr, *},
interpreter::{error::IResult, Interpreter},
interpreter::{env::Environment, error::IResult},
lexer::Lexer,
parser::{error::PResult, Parser},
pretty_printer::{PrettyPrintable, Printer},
@ -137,16 +137,15 @@ pub mod program {
.map(|ty| println!("{ty}"))
}
/// Runs the [Program] in the specified [Interpreter]
pub fn run(&self, interpreter: &mut Interpreter) -> IResult<()> {
match &self.data {
Parsed::Program(start) => interpreter.interpret(start),
Parsed::Expr(expr) => {
for value in interpreter.eval(expr)? {
println!("{value}")
}
Ok(())
pub fn run(&self, env: &mut Environment) -> IResult<()> {
println!(
"{}",
match &self.data {
Parsed::Program(start) => env.eval(start)?,
Parsed::Expr(expr) => env.eval(expr)?,
}
}
);
Ok(())
}
}
@ -162,7 +161,8 @@ pub mod program {
pub mod cli {
use conlang::{
interpreter::Interpreter, pretty_printer::PrettyPrintable, resolver::Resolver, token::Token,
interpreter::env::Environment, pretty_printer::PrettyPrintable, resolver::Resolver,
token::Token,
};
use crate::{
@ -231,7 +231,7 @@ pub mod cli {
}
(Mode::Beautify, Ok(program)) => Self::beautify(program),
(Mode::Resolve, Ok(program)) => Self::resolve(program, Default::default()),
(Mode::Interpret, Ok(program)) => Self::interpret(program, Default::default()),
(Mode::Interpret, Ok(program)) => Self::interpret(program, Environment::new()),
(_, Err(errors)) => {
for error in errors {
if let Some(path) = path {
@ -260,7 +260,7 @@ pub mod cli {
eprintln!("{e}");
}
}
fn interpret(program: Program<Tokenized>, mut interpreter: Interpreter) {
fn interpret(program: Program<Tokenized>, mut interpreter: Environment) {
let program = match program.parse() {
Ok(program) => program,
Err(e) => {
@ -316,7 +316,7 @@ pub mod cli {
prompt_again: &'static str, // " ?>"
prompt_begin: &'static str, // "cl>"
prompt_error: &'static str, // "! >"
interpreter: Interpreter,
env: Environment,
resolver: Resolver,
mode: Mode,
}
@ -327,7 +327,7 @@ pub mod cli {
prompt_begin: "cl>",
prompt_again: " ?>",
prompt_error: "! >",
interpreter: Default::default(),
env: Default::default(),
resolver: Default::default(),
mode: Default::default(),
}
@ -457,7 +457,7 @@ pub mod cli {
}
}
fn interpret(&mut self, code: &Program<Parsed>) {
if let Err(e) = code.run(&mut self.interpreter) {
if let Err(e) = code.run(&mut self.env) {
self.prompt_error(&e)
}
}

View File

@ -19,7 +19,6 @@ pub mod preamble {
path::*,
statement::*,
types::*,
visitor::Visitor,
*,
};
}
@ -156,7 +155,7 @@ pub mod statement {
/// # Syntax
#[derive(Clone, Debug)]
pub struct Name {
pub name: Identifier,
pub symbol: Identifier,
/// The mutability of the [Name]. Functions are never mutable.
pub mutable: bool,
/// The [type](TypeExpr)
@ -743,166 +742,6 @@ pub mod expression {
}
}
pub mod visitor {
//! A [`Visitor`] visits every kind of node in the [Abstract Syntax Tree](super)
//!
//! This trait is mostly here to ensure that every branch of the tree is accounted for.
//!
//! Default implementations are provided for
use super::{
expression::{call::*, control::*, math::*, tuple::*, Block, *},
literal::*,
statement::*,
*,
};
/// A Visitor traverses every kind of node in the [Abstract Syntax Tree](super)
#[deprecated]
pub trait Visitor<R> {
/// Visit the start of an AST
fn visit(&mut self, start: &Start) -> R {
self.visit_program(&start.0)
}
/// Visit a [Program]
fn visit_program(&mut self, prog: &Program) -> R;
/// Visit a [Statement](Stmt)
fn visit_statement(&mut self, stmt: &Stmt) -> R {
match stmt {
Stmt::Let(stmt) => self.visit_let(stmt),
Stmt::Fn(function) => self.visit_fn_decl(function),
Stmt::Expr(expr) => self.visit_expr(expr),
}
}
/// Visit a [Let statement](Let)
fn visit_let(&mut self, decl: &Let) -> R;
/// Visit a [Fn declaration](FnDecl)
fn visit_fn_decl(&mut self, decl: &FnDecl) -> R;
/// Visit an [Expression](Expr)
fn visit_expr(&mut self, expr: &Expr) -> R {
self.visit_operation(&expr.0)
}
// Block expression
/// Visit a [Block] expression
fn visit_block(&mut self, block: &Block) -> R;
/// Visit a [Group] expression
fn visit_group(&mut self, group: &Group) -> R {
match group {
Group::Tuple(tuple) => self.visit_tuple(tuple),
Group::Single(expr) => self.visit_expr(expr),
Group::Empty => self.visit_empty(),
}
}
/// Visit a [Tuple] expression
fn visit_tuple(&mut self, tuple: &Tuple) -> R;
/// Visit a [Call] expression
fn visit_call(&mut self, call: &Call) -> R {
match call {
Call::FnCall(call) => self.visit_fn_call(call),
Call::Primary(primary) => self.visit_primary(primary),
}
}
/// Visit a [Function Call](FnCall) expression
fn visit_fn_call(&mut self, call: &FnCall) -> R;
// Math expression
/// Visit an [Operation]
fn visit_operation(&mut self, operation: &Operation) -> R {
match operation {
Operation::Assign(assign) => self.visit_assign(assign),
Operation::Binary(binary) => self.visit_binary(binary),
Operation::Unary(unary) => self.visit_unary(unary),
Operation::Call(call) => self.visit_call(call),
}
}
/// Visit an [Assignment](Assign) operation
fn visit_assign(&mut self, assign: &Assign) -> R;
/// Visit a [Binary] Operation
fn visit_binary(&mut self, binary: &Binary) -> R;
/// Visit a [Unary] Operation
fn visit_unary(&mut self, unary: &Unary) -> R;
// Math operators
/// Visit an [Assignment](Assign) [operator](operator::Assign)
fn visit_assign_op(&mut self, op: &operator::Assign) -> R;
/// Visit a [Binary] [operator](operator::Binary)
fn visit_binary_op(&mut self, op: &operator::Binary) -> R;
/// Visit a [Unary] [operator](operator::Unary)
fn visit_unary_op(&mut self, op: &operator::Unary) -> R;
/// Visit a [Primary] expression
///
/// [`Primary`]` := `[`Identifier`]` | `[`Literal`]` | `[`Block`]` | `[`Flow`]
fn visit_primary(&mut self, primary: &Primary) -> R {
match primary {
Primary::Identifier(v) => self.visit_identifier(v),
Primary::Literal(v) => self.visit_literal(v),
Primary::Block(v) => self.visit_block(v),
Primary::Group(v) => self.visit_group(v),
Primary::Branch(v) => self.visit_branch(v),
}
}
/// Visit a [Flow] expression.
///
/// [`Flow`]` := `[`While`]` | `[`If`]` | `[`For`]`
/// | `[`Continue`]` | `[`Return`]` | `[`Break`]
fn visit_branch(&mut self, flow: &Flow) -> R {
match flow {
Flow::While(e) => self.visit_while(e),
Flow::If(e) => self.visit_if(e),
Flow::For(e) => self.visit_for(e),
Flow::Continue(e) => self.visit_continue(e),
Flow::Return(e) => self.visit_return(e),
Flow::Break(e) => self.visit_break(e),
}
}
/// Visit an [If] expression
fn visit_if(&mut self, expr: &If) -> R;
/// Visit a [While] loop expression
fn visit_while(&mut self, expr: &While) -> R;
/// Visit a [For] loop expression
fn visit_for(&mut self, expr: &For) -> R;
/// Visit an [Else] expression
fn visit_else(&mut self, expr: &Else) -> R;
/// Visit a [Continue] expression
fn visit_continue(&mut self, expr: &Continue) -> R;
/// Visit a [Break] expression
fn visit_break(&mut self, expr: &Break) -> R;
/// Visit a [Return] expression
fn visit_return(&mut self, expr: &Return) -> R;
// primary symbols
/// Visit an [Identifier]
fn visit_identifier(&mut self, ident: &Identifier) -> R;
/// Visit a [Literal]
///
/// [`Literal`]` := `[`String`]` | `[`char`]` | `[`bool`]` | `[`Float`]` | `[`u128`]
fn visit_literal(&mut self, literal: &Literal) -> R {
match literal {
Literal::String(l) => self.visit_string_literal(l),
Literal::Char(l) => self.visit_char_literal(l),
Literal::Bool(l) => self.visit_bool_literal(l),
Literal::Float(l) => self.visit_float_literal(l),
Literal::Int(l) => self.visit_int_literal(l),
}
}
/// Visit a [string](str) literal
fn visit_string_literal(&mut self, string: &str) -> R;
/// Visit a [character](char) literal
fn visit_char_literal(&mut self, char: &char) -> R;
/// Visit a [boolean](bool) literal
fn visit_bool_literal(&mut self, bool: &bool) -> R;
/// Visit a [floating point](Float) literal
fn visit_float_literal(&mut self, float: &Float) -> R;
/// Visit an [integer](u128) literal
fn visit_int_literal(&mut self, int: &u128) -> R;
/// Visit an Empty
fn visit_empty(&mut self) -> R;
}
}
pub mod todo {
//! temporary storage for pending expression work. \
//! when an item is in progress, remove it from todo.

View File

@ -2,15 +2,15 @@
#![allow(deprecated)] // TODO: REMOVE
use crate::ast::preamble::*;
use env::Environment;
use error::{Error, IResult};
use scope::Environment;
use temp_type_impl::ConValue;
/// Callable types can be called from within a Conlang program
pub trait Callable: std::fmt::Debug {
/// Calls this [Callable] in the provided [Interpreter], with [ConValue] args \
/// The Callable is responsible for checking the argument count and validating types
fn call(&self, interpreter: &mut Interpreter, args: &[ConValue]) -> IResult<ConValue>;
fn call(&self, interpreter: &mut Environment, args: &[ConValue]) -> IResult<ConValue>;
/// Returns the common name of this identifier.
fn name(&self) -> &str;
}
@ -25,7 +25,7 @@ pub mod temp_type_impl {
use super::{
error::{Error, IResult},
function::Function,
BuiltIn, Callable, Interpreter,
BuiltIn, Callable, Environment,
};
use std::ops::*;
/// A Conlang value
@ -106,7 +106,7 @@ pub mod temp_type_impl {
_ => "",
}
}
fn call(&self, interpreter: &mut Interpreter, args: &[ConValue]) -> IResult<ConValue> {
fn call(&self, interpreter: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
match self {
Self::Function(func) => func.call(interpreter, args),
Self::BuiltIn(func) => func.call(interpreter, args),
@ -284,129 +284,76 @@ pub mod temp_type_impl {
}
/// A work-in-progress tree walk interpreter for Conlang
#[derive(Clone, Debug)]
pub struct Interpreter {
scope: Box<Environment>,
stack: Vec<ConValue>,
pub trait Interpret {
/// Interprets this thing using the given [`Interpreter`].
///
/// Everything returns a value!™
fn interpret(&self, env: &mut Environment) -> IResult<ConValue>;
}
impl Interpreter {
/// Creates a new [Interpreter]
pub fn new() -> Self {
Default::default()
}
/// Interprets the [Start] of a syntax tree
pub fn interpret(&mut self, start: &Start) -> IResult<()> {
self.visit(start)
}
/// Calls a function inside the interpreter's scope,
/// and returns the result
pub fn call(&mut self, name: &str, args: &[ConValue]) -> IResult<ConValue> {
let function = self.resolve(name)?;
function.call(self, args)?;
self.pop()
}
/// Evaluates a single [Expression](expression::Expr) and returns the value stack.
pub fn eval(&mut self, expr: &expression::Expr) -> IResult<Vec<ConValue>> {
self.visit_expr(expr)?;
Ok(std::mem::take(&mut self.stack))
}
fn push(&mut self, value: impl Into<ConValue>) {
self.stack.push(value.into())
}
fn peek(&mut self) -> IResult<&ConValue> {
self.stack.last().ok_or(Error::StackUnderflow)
}
fn pop(&mut self) -> IResult<ConValue> {
self.stack.pop().ok_or(Error::StackUnderflow)
}
fn pop_two(&mut self) -> IResult<(ConValue, ConValue)> {
Ok((self.pop()?, self.pop()?))
}
fn resolve(&mut self, value: &str) -> IResult<ConValue> {
self.scope.get(value).cloned()
impl Interpret for Start {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
self.0.interpret(env)
}
}
impl Visitor<IResult<()>> for Interpreter {
fn visit_program(&mut self, prog: &Program) -> IResult<()> {
for stmt in &prog.0 {
self.visit_statement(stmt)?;
impl Interpret for Program {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
let mut out = ConValue::Empty;
for stmt in &self.0 {
out = stmt.interpret(env)?;
}
Ok(())
Ok(out)
}
fn visit_statement(&mut self, stmt: &Stmt) -> IResult<()> {
match stmt {
Stmt::Let(l) => self.visit_let(l),
Stmt::Fn(f) => self.visit_fn_decl(f),
Stmt::Expr(e) => {
self.visit_expr(e)?;
self.pop().map(drop)
}
}
impl Interpret for Stmt {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
match self {
Stmt::Let(l) => l.interpret(env),
Stmt::Fn(f) => f.interpret(env),
Stmt::Expr(e) => e.interpret(env),
}
}
fn visit_let(&mut self, stmt: &Let) -> IResult<()> {
let Let { name: Name { name: Identifier { name, .. }, .. }, init, .. } = stmt;
}
impl Interpret for Let {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
let Let { name: Name { symbol: Identifier { name, .. }, .. }, init, .. } = self;
if let Some(init) = init {
self.visit_expr(init)?;
let init = self.pop()?;
self.scope.insert(name, Some(init));
let init = init.interpret(env)?;
env.insert(name, Some(init));
} else {
self.scope.insert(name, None);
env.insert(name, None);
}
Ok(())
Ok(ConValue::Empty)
}
fn visit_fn_decl(&mut self, function: &FnDecl) -> IResult<()> {
}
impl Interpret for FnDecl {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
// register the function in the current environment
self.scope.insert_fn(function);
Ok(())
env.insert_fn(self);
Ok(ConValue::Empty)
}
fn visit_block(&mut self, block: &expression::Block) -> IResult<()> {
for stmt in &block.statements {
self.visit_statement(stmt)?;
}
if let Some(expr) = block.expr.as_ref() {
self.visit_expr(expr)
} else {
self.push(ConValue::Empty);
Ok(())
}
impl Interpret for Expr {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
self.0.interpret(env)
}
}
impl Interpret for Operation {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
match self {
Operation::Assign(op) => op.interpret(env),
Operation::Binary(op) => op.interpret(env),
Operation::Unary(op) => op.interpret(env),
Operation::Call(op) => op.interpret(env),
}
}
fn visit_tuple(&mut self, tuple: &Tuple) -> IResult<()> {
let mut out = vec![];
for expr in &tuple.elements {
self.visit_expr(expr)?;
out.push(self.pop()?);
}
self.push(out);
Ok(())
}
fn visit_fn_call(&mut self, call: &FnCall) -> IResult<()> {
// evaluate the callee
self.visit_primary(&call.callee)?;
for args in &call.args {
self.visit_tuple(args)?;
let (ConValue::Tuple(args), callee) = self.pop_two()? else {
Err(Error::TypeError)?
};
let return_value = callee.call(self, &args)?;
self.push(return_value);
}
Ok(())
}
fn visit_assign(&mut self, assign: &math::Assign) -> IResult<()> {
}
impl Interpret for Assign {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
use operator::Assign;
let math::Assign { target, operator, init } = assign;
self.visit_operation(init)?;
let init = self.pop()?;
let resolved = self.scope.get_mut(&target.name)?;
let math::Assign { target, operator, init } = self;
let init = init.interpret(env)?;
let resolved = env.get_mut(&target.name)?;
if let Assign::Assign = operator {
use std::mem::discriminant as variant;
@ -418,8 +365,7 @@ impl Visitor<IResult<()>> for Interpreter {
None => *resolved = Some(init),
_ => Err(Error::TypeError)?,
}
self.push(ConValue::Empty);
return Ok(());
return Ok(ConValue::Empty);
}
let Some(target) = resolved.as_mut() else {
@ -439,262 +385,251 @@ impl Visitor<IResult<()>> for Interpreter {
Assign::ShrAssign => target.shr_assign(init)?,
_ => (),
}
self.push(ConValue::Empty);
Ok(())
Ok(ConValue::Empty)
}
fn visit_binary(&mut self, bin: &math::Binary) -> IResult<()> {
let Binary { first, other } = bin;
self.visit_operation(first)?;
}
impl Interpret for Binary {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
let Binary { first, other } = self;
let mut first = first.interpret(env)?;
for (op, other) in other {
match op {
first = match op {
operator::Binary::LogAnd => {
if self.peek()?.truthy()? {
self.pop()?;
self.visit_operation(other)?;
if first.truthy()? {
other.interpret(env)
} else {
return Ok(first); // Short circuiting
}
}
operator::Binary::LogOr => {
if !self.peek()?.truthy()? {
self.pop()?;
self.visit_operation(other)?;
if !first.truthy()? {
other.interpret(env)
} else {
return Ok(first); // Short circuiting
}
}
operator::Binary::LogXor => {
let first = self.pop()?.truthy()?;
self.visit_operation(other)?;
let second = self.pop()?.truthy()?;
self.push(first ^ second);
// TODO: It should be possible to assemble better error information from this
let (lhs, rhs) = (first.truthy()?, other.interpret(env)?.truthy()?);
Ok(ConValue::Bool(lhs ^ rhs))
}
_ => {
self.visit_operation(other)?;
self.visit_binary_op(op)?;
}
}
// TODO: For all overloadable operators, transmute into function call
operator::Binary::Mul => first * other.interpret(env)?,
operator::Binary::Div => first / other.interpret(env)?,
operator::Binary::Rem => first % other.interpret(env)?,
operator::Binary::Add => first + other.interpret(env)?,
operator::Binary::Sub => first - other.interpret(env)?,
operator::Binary::Lsh => first << other.interpret(env)?,
operator::Binary::Rsh => first >> other.interpret(env)?,
operator::Binary::BitAnd => first & other.interpret(env)?,
operator::Binary::BitOr => first | other.interpret(env)?,
operator::Binary::BitXor => first ^ other.interpret(env)?,
operator::Binary::RangeExc => first.range_exc(other.interpret(env)?),
operator::Binary::RangeInc => first.range_inc(other.interpret(env)?),
operator::Binary::Less => first.lt(&other.interpret(env)?),
operator::Binary::LessEq => first.lt_eq(&other.interpret(env)?),
operator::Binary::Equal => first.eq(&other.interpret(env)?),
operator::Binary::NotEq => first.neq(&other.interpret(env)?),
operator::Binary::GreaterEq => first.gt_eq(&other.interpret(env)?),
operator::Binary::Greater => first.gt(&other.interpret(env)?),
}?;
}
Ok(())
}
fn visit_unary(&mut self, unary: &math::Unary) -> IResult<()> {
let Unary { operand, operators } = unary;
self.visit_operation(operand)?;
for op in operators.iter().rev() {
self.visit_unary_op(op)?;
}
Ok(())
}
fn visit_assign_op(&mut self, _: &operator::Assign) -> IResult<()> {
unimplemented!("visit_assign_op is implemented in visit_operation")
}
fn visit_binary_op(&mut self, op: &operator::Binary) -> IResult<()> {
use operator::Binary;
let (second, first) = self.pop_two()?;
let out = match op {
Binary::Mul => first * second,
Binary::Div => first / second,
Binary::Rem => first % second,
Binary::Add => first + second,
Binary::Sub => first - second,
Binary::Lsh => first << second,
Binary::Rsh => first >> second,
Binary::BitAnd => first & second,
Binary::BitOr => first | second,
Binary::BitXor => first ^ second,
Binary::LogAnd | Binary::LogOr | Binary::LogXor => {
unimplemented!("Implemented in visit_operation")
}
Binary::RangeExc => first.range_exc(second),
Binary::RangeInc => first.range_inc(second),
Binary::Less => first.lt(&second),
Binary::LessEq => first.lt_eq(&second),
Binary::Equal => first.eq(&second),
Binary::NotEq => first.neq(&second),
Binary::GreaterEq => first.gt_eq(&second),
Binary::Greater => first.gt(&second),
}?;
self.push(out);
Ok(())
}
fn visit_unary_op(&mut self, op: &operator::Unary) -> IResult<()> {
let operand = self.pop()?;
self.push(match op {
operator::Unary::RefRef => todo!(),
operator::Unary::Ref => todo!(),
operator::Unary::Deref => todo!(),
operator::Unary::Neg => (-operand)?,
operator::Unary::Not => (!operand)?,
operator::Unary::At => todo!(),
operator::Unary::Hash => {
println!("{operand}");
operand
}
operator::Unary::Tilde => todo!(),
});
Ok(())
}
fn visit_if(&mut self, expr: &If) -> IResult<()> {
self.visit_expr(&expr.cond)?;
if self.pop()?.truthy()? {
self.visit_block(&expr.body)?;
} else if let Some(block) = &expr.else_ {
self.visit_else(block)?;
} else {
self.push(ConValue::Empty)
}
Ok(())
}
fn visit_while(&mut self, expr: &While) -> IResult<()> {
while {
self.visit_expr(&expr.cond)?;
self.pop()?.truthy()?
} {
let Err(out) = self.visit_block(&expr.body) else {
// Every expression returns a value. If allowed to pile up, they'll overflow the
// stack.
self.pop()?;
continue;
};
match out {
Error::Continue => continue,
Error::Break(value) => {
self.push(value);
return Ok(());
}
r => Err(r)?,
}
}
if let Some(r#else) = &expr.else_ {
self.visit_else(r#else)?;
} else {
self.push(ConValue::Empty);
}
Ok(())
}
fn visit_for(&mut self, expr: &control::For) -> IResult<()> {
self.scope.enter();
self.visit_expr(&expr.iter)?;
let bounds = match self.pop()? {
ConValue::RangeExc(a, b) | ConValue::RangeInc(a, b) => (a, b),
_ => Err(Error::NotIterable)?,
};
for loop_var in bounds.0..=bounds.1 {
self.scope.insert(&expr.var.name, Some(loop_var.into()));
let Err(out) = self.visit_block(&expr.body) else {
self.pop()?;
continue;
};
match out {
Error::Continue => continue,
Error::Break(value) => {
self.push(value);
return Ok(());
}
r => Err(r)?,
}
}
if let Some(r#else) = &expr.else_ {
self.visit_else(r#else)?;
} else {
self.push(ConValue::Empty)
}
self.scope.exit()?;
Ok(())
}
fn visit_else(&mut self, else_: &control::Else) -> IResult<()> {
self.visit_expr(&else_.expr)
}
fn visit_continue(&mut self, _: &control::Continue) -> IResult<()> {
Err(Error::cnt())
}
fn visit_break(&mut self, brk: &control::Break) -> IResult<()> {
Err(Error::brk({
self.visit_expr(&brk.expr)?;
self.pop()?
}))
}
fn visit_return(&mut self, ret: &control::Return) -> IResult<()> {
Err(Error::ret({
self.visit_expr(&ret.expr)?;
self.pop()?
}))
}
fn visit_identifier(&mut self, ident: &Identifier) -> IResult<()> {
let value = self.resolve(&ident.name)?;
self.push(value);
Ok(())
}
fn visit_string_literal(&mut self, string: &str) -> IResult<()> {
self.push(string);
Ok(())
}
fn visit_char_literal(&mut self, char: &char) -> IResult<()> {
self.push(*char);
Ok(())
}
fn visit_bool_literal(&mut self, bool: &bool) -> IResult<()> {
self.push(*bool);
Ok(())
}
fn visit_float_literal(&mut self, float: &literal::Float) -> IResult<()> {
todo!("visit floats in interpreter: {float:?}")
}
fn visit_int_literal(&mut self, int: &u128) -> IResult<()> {
self.push((*int) as i128);
Ok(())
}
fn visit_empty(&mut self) -> IResult<()> {
self.push(());
Ok(())
Ok(first)
}
}
impl Interpret for Unary {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
let Unary { operand, operators } = self;
let mut operand = operand.interpret(env)?;
impl Default for Interpreter {
fn default() -> Self {
Self { scope: Environment::new().into(), stack: Default::default() }
for op in operators.iter().rev() {
operand = match op {
operator::Unary::RefRef => todo!(),
operator::Unary::Ref => todo!(),
operator::Unary::Deref => todo!(),
operator::Unary::Neg => (-operand)?,
operator::Unary::Not => (!operand)?,
operator::Unary::At => todo!(),
operator::Unary::Hash => {
println!("{operand}");
operand
}
operator::Unary::Tilde => todo!(),
};
}
Ok(operand)
}
}
impl Interpret for Call {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
match self {
Call::FnCall(fncall) => fncall.interpret(env),
Call::Primary(primary) => primary.interpret(env),
}
}
}
impl Interpret for FnCall {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
// evaluate the callee
let mut callee = self.callee.interpret(env)?;
for args in &self.args {
let ConValue::Tuple(args) = args.interpret(env)? else {
Err(Error::TypeError)?
};
callee = callee.call(env, &args)?;
}
Ok(callee)
}
}
impl Interpret for Primary {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
match self {
Primary::Identifier(prim) => prim.interpret(env),
Primary::Literal(prim) => prim.interpret(env),
Primary::Block(prim) => prim.interpret(env),
Primary::Group(prim) => prim.interpret(env),
Primary::Branch(prim) => prim.interpret(env),
}
}
}
impl Interpret for Identifier {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
env.resolve(&self.name)
}
}
impl Interpret for Literal {
fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
Ok(match self {
Literal::String(value) => ConValue::from(value.as_str()),
Literal::Char(value) => ConValue::Char(*value),
Literal::Bool(value) => ConValue::Bool(*value),
Literal::Float(value) => todo!("Float values in interpreter: {value:?}"),
Literal::Int(value) => ConValue::Int(*value as _),
})
}
}
impl Interpret for Block {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
let mut env = env.frame("block");
// TODO: this could TOTALLY be done with a binary operator.
for stmt in &self.statements {
stmt.interpret(&mut env)?;
}
if let Some(expr) = self.expr.as_ref() {
expr.interpret(&mut env)
} else {
Ok(ConValue::Empty)
}
}
}
impl Interpret for Group {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
match self {
Group::Tuple(tuple) => tuple.interpret(env),
Group::Single(value) => value.interpret(env),
Group::Empty => Ok(ConValue::Empty),
}
}
}
impl Interpret for Tuple {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
Ok(ConValue::Tuple(self.elements.iter().try_fold(
vec![],
|mut out, element| {
out.push(element.interpret(env)?);
Ok(out)
},
)?))
}
}
impl Interpret for Flow {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
match self {
Flow::While(flow) => flow.interpret(env),
Flow::If(flow) => flow.interpret(env),
Flow::For(flow) => flow.interpret(env),
Flow::Continue(flow) => flow.interpret(env),
Flow::Return(flow) => flow.interpret(env),
Flow::Break(flow) => flow.interpret(env),
}
}
}
impl Interpret for While {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
while self.cond.interpret(env)?.truthy()? {
match self.body.interpret(env) {
Err(Error::Break(value)) => return Ok(value),
Err(Error::Continue) => continue,
e => e?,
};
}
if let Some(other) = &self.else_ {
other.interpret(env)
} else {
Ok(ConValue::Empty)
}
}
}
impl Interpret for Else {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
self.expr.interpret(env)
}
}
impl Interpret for If {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
if self.cond.interpret(env)?.truthy()? {
self.body.interpret(env)
} else if let Some(other) = &self.else_ {
other.interpret(env)
} else {
Ok(ConValue::Empty)
}
}
}
impl Interpret for For {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
let bounds = match self.iter.interpret(env)? {
ConValue::RangeExc(a, b) => a..=b,
ConValue::RangeInc(a, b) => a..=b,
_ => Err(Error::TypeError)?,
};
let mut env = env.frame("loop variable");
for loop_var in bounds {
env.insert(&self.var.name, Some(loop_var.into()));
match self.body.interpret(&mut env) {
Err(Error::Break(value)) => return Ok(value),
Err(Error::Continue) => continue,
result => result?,
};
}
if let Some(other) = &self.else_ {
other.interpret(&mut env)
} else {
Ok(ConValue::Empty)
}
}
}
impl Interpret for Continue {
fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
Err(Error::Continue)
}
}
impl Interpret for Return {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
Err(Error::Return(self.expr.interpret(env)?))
}
}
impl Interpret for Break {
fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
Err(Error::Return(self.expr.interpret(env)?))
}
}
pub mod function {
//! Represents a block of code which lives inside the Interpreter
use super::{
// scope::Environment,
Callable,
ConValue,
Error,
FnDecl,
IResult,
Identifier,
Interpreter,
};
use crate::ast::{preamble::Name, visitor::Visitor};
use super::{Callable, ConValue, Environment, Error, FnDecl, IResult, Identifier, Interpret};
use crate::ast::preamble::Name;
/// Represents a block of code which persists inside the Interpreter
#[derive(Clone, Debug)]
pub struct Function {
@ -716,9 +651,9 @@ pub mod function {
impl Callable for Function {
fn name(&self) -> &str {
&self.declaration.name.name.name
&self.declaration.name.symbol.name
}
fn call(&self, interpreter: &mut Interpreter, args: &[ConValue]) -> IResult<ConValue> {
fn call(&self, env: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
// Check arg mapping
if args.len() != self.declaration.args.len() {
return Err(Error::ArgNumber {
@ -727,20 +662,18 @@ pub mod function {
});
}
// TODO: Isolate cross-function scopes!
interpreter.scope.enter();
for (Name { name: Identifier { name, .. }, .. }, value) in
let mut frame = env.frame("function args");
for (Name { symbol: Identifier { name, .. }, .. }, value) in
self.declaration.args.iter().zip(args)
{
interpreter.scope.insert(name, Some(value.clone()));
frame.insert(name, Some(value.clone()));
}
match interpreter.visit_block(&self.declaration.body) {
Err(Error::Return(value)) => interpreter.push(value),
Err(Error::Break(value)) => Err(Error::BadBreak(value))?,
Err(e) => Err(e)?,
Ok(()) => (),
match self.declaration.body.interpret(&mut frame) {
Err(Error::Return(value)) => Ok(value),
Err(Error::Break(value)) => Err(Error::BadBreak(value)),
result => result,
}
interpreter.scope.exit()?;
interpreter.pop()
}
}
}
@ -748,7 +681,7 @@ pub mod function {
pub mod builtin {
mod builtin_imports {
pub use crate::interpreter::{
error::IResult, temp_type_impl::ConValue, BuiltIn, Callable, Interpreter,
env::Environment, error::IResult, temp_type_impl::ConValue, BuiltIn, Callable,
};
}
use super::BuiltIn;
@ -765,7 +698,7 @@ pub mod builtin {
#[rustfmt::skip]
impl Callable for Print {
fn name(&self) -> &'static str { "print" }
fn call(&self, _inter: &mut Interpreter, args: &[ConValue]) -> IResult<ConValue> {
fn call(&self, _inter: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
for arg in args {
print!("{arg}")
}
@ -783,22 +716,20 @@ pub mod builtin {
#[rustfmt::skip]
impl Callable for Dbg {
fn name(&self) -> &str { "dbg" }
fn call(&self, _inter: &mut Interpreter, args: &[ConValue]) -> IResult<ConValue> {
fn call(&self, _inter: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
println!("{args:?}");
Ok(args.into())
}
}
}
mod dump {
use super::builtin_imports::*;
#[derive(Clone, Debug)]
pub struct Dump;
impl BuiltIn for Dump {}
impl Callable for Dump {
fn call(&self, interpreter: &mut Interpreter, _args: &[ConValue]) -> IResult<ConValue> {
println!("Scope:\n{}", interpreter.scope);
println!("Stack:{:#?}", interpreter.stack);
fn call(&self, env: &mut Environment, _args: &[ConValue]) -> IResult<ConValue> {
println!("{}", *env);
Ok(ConValue::Empty)
}
@ -809,7 +740,7 @@ pub mod builtin {
}
}
pub mod scope {
pub mod env {
//! Lexical and non-lexical scoping for variables
use super::{
@ -817,52 +748,76 @@ pub mod scope {
error::{Error, IResult},
function::Function,
temp_type_impl::ConValue,
FnDecl,
Callable, FnDecl, Interpret,
};
use std::{
collections::HashMap,
fmt::Display,
ops::{Deref, DerefMut},
};
use std::{collections::HashMap, fmt::Display};
/// Implements a nested lexical scope
#[derive(Clone, Debug, Default)]
#[derive(Clone, Debug)]
pub struct Environment {
outer: Option<Box<Self>>,
vars: HashMap<String, Option<ConValue>>,
name: &'static str,
}
impl Display for Environment {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
writeln!(f, "--- '{}' ---", self.name)?;
for (var, val) in &self.vars {
writeln!(f, "{var}: {}", if val.is_some() { "..." } else { "None" })?;
write!(f, "{var}: ")?;
match val {
Some(value) => writeln!(f, "{value}"),
None => writeln!(f, "<undefined>"),
}?
}
"--- Frame ---\n".fmt(f)?;
if let Some(outer) = &self.outer {
outer.fmt(f)?;
}
Ok(())
}
}
impl Default for Environment {
fn default() -> Self {
let mut outer = Self::no_builtins("builtins");
for &builtin in DEFAULT_BUILTINS {
outer.insert(builtin.name(), Some(ConValue::BuiltIn(builtin)));
}
Self { outer: Some(Box::new(outer)), vars: Default::default(), name: "base" }
}
}
impl Environment {
pub fn new() -> Self {
let mut out = Self::default();
for &builtin in DEFAULT_BUILTINS {
out.insert(builtin.name(), Some(ConValue::BuiltIn(builtin)))
}
out
Self::default()
}
/// Enter a nested scope
pub fn enter(&mut self) {
let outer = std::mem::take(self);
self.outer = Some(outer.into());
fn no_builtins(name: &'static str) -> Self {
Self { outer: None, vars: Default::default(), name }
}
/// Exits the scope, destroying all local variables and
/// returning the outer scope, if there is one
pub fn exit(&mut self) -> IResult<()> {
if let Some(outer) = std::mem::take(&mut self.outer) {
*self = *outer;
Ok(())
} else {
Err(Error::ScopeExit)
}
/// Temporary function
#[deprecated]
pub fn resolve(&mut self, name: &str) -> IResult<ConValue> {
self.get(name).cloned()
}
pub fn eval(&mut self, node: &impl Interpret) -> IResult<ConValue> {
node.interpret(self)
}
/// Calls a function inside the interpreter's scope,
/// and returns the result
pub fn call(&mut self, name: &str, args: &[ConValue]) -> IResult<ConValue> {
let function = self.resolve(name)?;
function.call(self, args)
}
/// Enters a nested scope, returning a [`Frame`] stack-guard.
///
/// [`Frame`] implements Deref/DerefMut for [`Environment`].
pub fn frame(&mut self, name: &'static str) -> Frame {
Frame::new(self, name)
}
/// Resolves a variable mutably
///
@ -894,11 +849,62 @@ pub mod scope {
/// A convenience function for registering a [FnDecl] as a [Function]
pub fn insert_fn(&mut self, decl: &FnDecl) {
self.vars.insert(
decl.name.name.name.clone(),
decl.name.symbol.name.clone(),
Some(Function::new(decl).into()),
);
}
}
/// Functions which aid in the implementation of [`Frame`]
impl Environment {
/// Enters a scope, creating a new namespace for variables
fn enter(&mut self, name: &'static str) -> &mut Self {
let outer = std::mem::replace(self, Environment::no_builtins(name));
self.outer = Some(outer.into());
self
}
/// Exits the scope, destroying all local variables and
/// returning the outer scope, if there is one
fn exit(&mut self) -> &mut Self {
if let Some(outer) = std::mem::take(&mut self.outer) {
*self = *outer;
}
self
}
}
/// Represents a stack frame
#[derive(Debug)]
pub struct Frame<'scope> {
scope: &'scope mut Environment,
}
impl<'scope> Frame<'scope> {
fn new(scope: &'scope mut Environment, name: &'static str) -> Self {
Self { scope: scope.enter(name) }
}
}
impl<'scope> Deref for Frame<'scope> {
type Target = Environment;
fn deref(&self) -> &Self::Target {
self.scope
}
}
impl<'scope> DerefMut for Frame<'scope> {
fn deref_mut(&mut self) -> &mut Self::Target {
self.scope
}
}
impl<'scope> Drop for Frame<'scope> {
fn drop(&mut self) {
self.scope.exit();
}
}
}
pub mod module {
//! Implements non-lexical "global" scoping rules
}
pub mod error {

View File

@ -425,7 +425,7 @@ impl Parser {
} else {
None
};
Ok(FnDecl { name: Name { name, mutable: false, ty }, args, body: self.block()? })
Ok(FnDecl { name: Name { symbol: name, mutable: false, ty }, args, body: self.block()? })
}
/// Parses a [parameter](Name) list for [FnDecl]
fn params(&mut self) -> PResult<Vec<Name>> {
@ -442,7 +442,7 @@ impl Parser {
fn name(&mut self) -> PResult<Name> {
Ok(Name {
mutable: self.keyword(Keyword::Mut).is_ok(),
name: self.identifier()?,
symbol: self.identifier()?,
ty: self
.consume_type(Type::Colon)
.and_then(|this| this.type_expr())
@ -473,7 +473,7 @@ impl Parser {
Type::Keyword(Keyword::SelfKw) => {
self.keyword(Keyword::SelfKw).map(|_| PathPart::PathSelf)
}
e => Err(Error::not_path_segment(e))
e => Err(Error::not_path_segment(e)),
}
}
}

View File

@ -108,7 +108,7 @@ impl PrettyPrintable for Stmt {
}
impl PrettyPrintable for Let {
fn visit<W: Write>(&self, p: &mut Printer<W>) -> IOResult<()> {
let Let { name: Name { name, mutable, ty }, init } = self;
let Let { name: Name { symbol: name, mutable, ty }, init } = self;
p.put("let")?.space()?;
if *mutable {
p.put("mut")?.space()?;
@ -144,7 +144,7 @@ impl PrettyPrintable for Name {
if self.mutable {
p.put("mut")?.space()?;
}
self.name.visit(p)?;
self.symbol.visit(p)?;
if let Some(ty) = &self.ty {
ty.visit(p.put(':')?.space()?)?;
}
@ -168,7 +168,9 @@ impl PrettyPrintable for Path {
p.put("::")?;
}
for (idx, part) in parts.iter().enumerate() {
if idx != 0 { p.put("::")?;}
if idx != 0 {
p.put("::")?;
}
part.visit(p)?;
}
Ok(())
@ -179,7 +181,7 @@ impl PrettyPrintable for PathPart {
match self {
PathPart::PathSuper => p.put("super").map(drop),
PathPart::PathSelf => p.put("self").map(drop),
PathPart::PathIdent(id) =>id.visit(p),
PathPart::PathIdent(id) => id.visit(p),
}
}
}