From 1ff7a2686c2d7e405e597f9ac8a96189ec161d58 Mon Sep 17 00:00:00 2001 From: Vincent Ambo Date: Mon, 18 Jan 2021 03:21:52 +0300 Subject: refactor(tazjin/rlox): Add Interpreter trait for switching impls Change-Id: Iae28d64ce879014c5e5d7e145c536c1f16ad307d Reviewed-on: https://cl.tvl.fyi/c/depot/+/2418 Reviewed-by: tazjin Tested-by: BuildkiteCI --- users/tazjin/rlox/src/bytecode/errors.rs | 8 +++ users/tazjin/rlox/src/bytecode/mod.rs | 34 ++++++++----- users/tazjin/rlox/src/bytecode/vm.rs | 9 ++-- users/tazjin/rlox/src/main.rs | 59 +++++++++++++++++++++- users/tazjin/rlox/src/treewalk/errors.rs | 7 ++- users/tazjin/rlox/src/treewalk/interpreter.rs | 46 ++++++++++------- .../tazjin/rlox/src/treewalk/interpreter/tests.rs | 8 +-- users/tazjin/rlox/src/treewalk/mod.rs | 56 -------------------- 8 files changed, 125 insertions(+), 102 deletions(-) diff --git a/users/tazjin/rlox/src/bytecode/errors.rs b/users/tazjin/rlox/src/bytecode/errors.rs index 89ab1867a4..c7871bc384 100644 --- a/users/tazjin/rlox/src/bytecode/errors.rs +++ b/users/tazjin/rlox/src/bytecode/errors.rs @@ -1,3 +1,5 @@ +use std::fmt; + #[derive(Debug)] pub enum ErrorKind { // CompileError, @@ -10,4 +12,10 @@ pub struct Error { pub kind: ErrorKind, } +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "[line NYI] Error: {:?}", self.kind) + } +} + pub type LoxResult = Result; diff --git a/users/tazjin/rlox/src/bytecode/mod.rs b/users/tazjin/rlox/src/bytecode/mod.rs index 2d83c42722..31278f8c4b 100644 --- a/users/tazjin/rlox/src/bytecode/mod.rs +++ b/users/tazjin/rlox/src/bytecode/mod.rs @@ -9,19 +9,29 @@ mod value; mod vm; use chunk::Chunk; -use opcode::OpCode; +pub struct Interpreter {} -pub fn main() { - let mut chunk: Chunk = Default::default(); +impl crate::Lox for Interpreter { + type Error = errors::Error; + type Value = value::Value; - let constant = chunk.add_constant(1.2); - chunk.add_op(OpCode::OpConstant(constant), 1); + fn create() -> Self { + Interpreter {} + } - let constant = chunk.add_constant(2.0); - chunk.add_op(OpCode::OpConstant(constant), 2); - - chunk.add_op(OpCode::OpAdd, 3); - chunk.add_op(OpCode::OpReturn, 4); - - vm::interpret(chunk).expect("it should work"); + fn interpret(&mut self, _: String) -> Result> { + let chunk: Chunk = Default::default(); + vm::interpret(chunk).map_err(|e| vec![e]) + } } + +// pub fn main() { +// let mut chunk: Chunk = Default::default(); +// let constant = chunk.add_constant(1.2); +// chunk.add_op(OpCode::OpConstant(constant), 1); +// let constant = chunk.add_constant(2.0); +// chunk.add_op(OpCode::OpConstant(constant), 2); +// chunk.add_op(OpCode::OpAdd, 3); +// chunk.add_op(OpCode::OpReturn, 4); +// vm::interpret(chunk).expect("it should work"); +// } diff --git a/users/tazjin/rlox/src/bytecode/vm.rs b/users/tazjin/rlox/src/bytecode/vm.rs index fd91cd7be6..33bc358f44 100644 --- a/users/tazjin/rlox/src/bytecode/vm.rs +++ b/users/tazjin/rlox/src/bytecode/vm.rs @@ -32,7 +32,7 @@ macro_rules! binary_op { } impl VM { - fn run(&mut self) -> LoxResult<()> { + fn run(&mut self) -> LoxResult { loop { let op = &self.chunk.code[self.ip]; @@ -42,10 +42,7 @@ impl VM { self.ip += 1; match op { - OpCode::OpReturn => { - println!("{:?}", self.pop()); - return Ok(()); - } + OpCode::OpReturn => return Ok(self.pop()), OpCode::OpConstant(idx) => { let c = *self.chunk.constant(*idx); @@ -66,7 +63,7 @@ impl VM { } } -pub fn interpret(chunk: chunk::Chunk) -> LoxResult<()> { +pub fn interpret(chunk: chunk::Chunk) -> LoxResult { let mut vm = VM { chunk, ip: 0, diff --git a/users/tazjin/rlox/src/main.rs b/users/tazjin/rlox/src/main.rs index e3bc278315..c9cc96d2e6 100644 --- a/users/tazjin/rlox/src/main.rs +++ b/users/tazjin/rlox/src/main.rs @@ -7,9 +7,64 @@ use std::process; mod bytecode; mod treewalk; +/// Trait for making the different interpreters callable in the same +/// way. +pub trait Lox { + type Value; + type Error: std::fmt::Display; + + fn create() -> Self; + fn interpret(&mut self, source: String) -> Result>; +} + fn main() { + let mut args = env::args(); + if args.len() > 2 { + println!("Usage: rlox [script]"); + process::exit(1); + } + match env::var("LOX_INTERPRETER").as_ref().map(String::as_str) { - Ok("treewalk") => treewalk::main(), - _ => bytecode::main(), + Ok("treewalk") => pick::(args.nth(1)), + _ => pick::(args.nth(1)), + } +} + +fn pick(file_arg: Option) { + if let Some(file) = file_arg { + run_file::(&file); + } else { + run_prompt::(); + } +} + +// Run Lox code from a file and print results to stdout +fn run_file(file: &str) { + let contents = fs::read_to_string(file).expect("failed to read the input file"); + let mut lox = I::create(); + run(&mut lox, contents); +} + +// Evaluate Lox code interactively in a shitty REPL. +fn run_prompt() { + let mut line = String::new(); + let mut lox = I::create(); + + loop { + print!("> "); + io::stdout().flush().unwrap(); + io::stdin() + .read_line(&mut line) + .expect("failed to read user input"); + run(&mut lox, std::mem::take(&mut line)); + line.clear(); + } +} + +fn run(lox: &mut I, code: String) { + if let Err(errors) = lox.interpret(code) { + for error in errors { + eprintln!("{}", error); + } } } diff --git a/users/tazjin/rlox/src/treewalk/errors.rs b/users/tazjin/rlox/src/treewalk/errors.rs index 3d5c28f9f3..54d2718eed 100644 --- a/users/tazjin/rlox/src/treewalk/errors.rs +++ b/users/tazjin/rlox/src/treewalk/errors.rs @@ -1,4 +1,5 @@ use crate::treewalk::interpreter::Value; +use std::fmt; #[derive(Debug)] pub enum ErrorKind { @@ -33,6 +34,8 @@ pub struct Error { pub kind: ErrorKind, } -pub fn report(err: &Error) { - eprintln!("[line {}] Error: {:?}", err.line, err.kind); +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "[line {}] Error: {:?}", self.line, self.kind) + } } diff --git a/users/tazjin/rlox/src/treewalk/interpreter.rs b/users/tazjin/rlox/src/treewalk/interpreter.rs index a096716d91..1263e6cb81 100644 --- a/users/tazjin/rlox/src/treewalk/interpreter.rs +++ b/users/tazjin/rlox/src/treewalk/interpreter.rs @@ -1,7 +1,8 @@ use crate::treewalk::errors::{Error, ErrorKind}; use crate::treewalk::parser::{self, Block, Expr, Literal, Statement}; +use crate::treewalk::resolver; use crate::treewalk::scanner::{self, TokenKind}; -use crate::treewalk::treewalk::resolver; +use crate::Lox; use std::collections::HashMap; use std::rc::Rc; use std::sync::RwLock; @@ -174,10 +175,13 @@ pub struct Interpreter { env: Rc>, } -impl Interpreter { +impl Lox for Interpreter { + type Value = Value; + type Error = Error; + /// Create a new interpreter and configure the initial global /// variable set. - pub fn create() -> Self { + fn create() -> Self { let mut globals = HashMap::new(); globals.insert( @@ -193,6 +197,27 @@ impl Interpreter { } } + fn interpret(&mut self, code: String) -> Result> { + let chars: Vec = code.chars().collect(); + + let mut program = scanner::scan(&chars).and_then(|tokens| parser::parse(tokens))?; + + let globals = self + .env + .read() + .expect("static globals lock poisoned") + .values + .keys() + .map(Clone::clone) + .collect::>(); + + resolver::resolve(&globals, &mut program).map_err(|e| vec![e])?; + self.interpret_block_with_env(None, &program) + .map_err(|e| vec![e]) + } +} + +impl Interpreter { // Environment modification helpers fn define_var(&mut self, name: &scanner::Token, value: Value) -> Result<(), Error> { self.env @@ -221,21 +246,6 @@ impl Interpreter { .get(ident, var.name.line, depth) } - // Interpreter itself - pub fn interpret(&mut self, mut program: Block) -> Result { - let globals = self - .env - .read() - .expect("static globals lock poisoned") - .values - .keys() - .map(Clone::clone) - .collect::>(); - - resolver::resolve(&globals, &mut program)?; - self.interpret_block_with_env(None, &program) - } - /// Interpret the block in the supplied environment. If no /// environment is supplied, a new one is created using the /// current one as its parent. diff --git a/users/tazjin/rlox/src/treewalk/interpreter/tests.rs b/users/tazjin/rlox/src/treewalk/interpreter/tests.rs index 34b1df34b0..2fc6f4fee9 100644 --- a/users/tazjin/rlox/src/treewalk/interpreter/tests.rs +++ b/users/tazjin/rlox/src/treewalk/interpreter/tests.rs @@ -2,13 +2,9 @@ use super::*; /// Evaluate a code snippet, returning a value. fn parse_eval(code: &str) -> Value { - let chars: Vec = code.chars().collect(); - let tokens = scanner::scan(&chars).expect("could not scan code"); - let program = parser::parse(tokens).expect("could not parse code"); - Interpreter::create() - .interpret(program) - .expect("could not eval code") + .interpret(code.into()) + .expect("could not interpret code") } #[test] diff --git a/users/tazjin/rlox/src/treewalk/mod.rs b/users/tazjin/rlox/src/treewalk/mod.rs index b5db454ccc..d53bd13f8e 100644 --- a/users/tazjin/rlox/src/treewalk/mod.rs +++ b/users/tazjin/rlox/src/treewalk/mod.rs @@ -1,61 +1,5 @@ -use crate::*; - mod errors; pub mod interpreter; mod parser; mod resolver; mod scanner; - -pub fn main() { - let mut args = env::args(); - - if args.len() > 2 { - println!("Usage: rlox [script]"); - process::exit(1); - } else if let Some(file) = args.nth(1) { - run_file(&file); - } else { - run_prompt(); - } -} - -// Run Lox code from a file and print results to stdout -fn run_file(file: &str) { - let contents = fs::read_to_string(file).expect("failed to read the input file"); - let mut lox = treewalk::interpreter::Interpreter::create(); - run(&mut lox, &contents); -} - -// Evaluate Lox code interactively in a shitty REPL. -fn run_prompt() { - let mut line = String::new(); - let mut lox = treewalk::interpreter::Interpreter::create(); - - loop { - print!("> "); - io::stdout().flush().unwrap(); - io::stdin() - .read_line(&mut line) - .expect("failed to read user input"); - run(&mut lox, &line); - line.clear(); - } -} - -fn run(lox: &mut treewalk::interpreter::Interpreter, code: &str) { - let chars: Vec = code.chars().collect(); - - let result = scanner::scan(&chars) - .and_then(|tokens| parser::parse(tokens)) - .and_then(|program| lox.interpret(program).map_err(|e| vec![e])); - - if let Err(errors) = result { - report_errors(errors); - } -} - -fn report_errors(errors: Vec) { - for error in errors { - errors::report(&error); - } -} -- cgit 1.4.1