From 995d024f03d99726de5b22bdf5aaa04a88e00b4a Mon Sep 17 00:00:00 2001
From: Vincent Ambo <mail@tazj.in>
Date: Sun, 28 Feb 2021 01:13:52 +0200
Subject: feat(tazjin/rlox): Wire up bytecode interpreter & print results

This makes the bytecode interpreter actually usable.

Change-Id: I24afc7ce461c6673dc42581378f6e14da7aece5c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2566
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI
---
 users/tazjin/rlox/src/bytecode/compiler.rs     | 287 +++++++++++++++++++++++++
 users/tazjin/rlox/src/bytecode/compiler/mod.rs | 287 -------------------------
 users/tazjin/rlox/src/bytecode/mod.rs          |  11 -
 users/tazjin/rlox/src/main.rs                  |  11 +-
 4 files changed, 294 insertions(+), 302 deletions(-)
 create mode 100644 users/tazjin/rlox/src/bytecode/compiler.rs
 delete mode 100644 users/tazjin/rlox/src/bytecode/compiler/mod.rs

(limited to 'users/tazjin/rlox')

diff --git a/users/tazjin/rlox/src/bytecode/compiler.rs b/users/tazjin/rlox/src/bytecode/compiler.rs
new file mode 100644
index 000000000000..ca56bfe7cf50
--- /dev/null
+++ b/users/tazjin/rlox/src/bytecode/compiler.rs
@@ -0,0 +1,287 @@
+use super::chunk::{self, Chunk};
+use super::errors::{Error, ErrorKind, LoxResult};
+use super::opcode::OpCode;
+use super::value::Value;
+use crate::scanner::{self, Token, TokenKind};
+
+struct Compiler<T: Iterator<Item = Token>> {
+    tokens: T,
+    chunk: Chunk,
+    panic: bool,
+    errors: Vec<Error>,
+
+    // TODO(tazjin): Restructure so that these don't need to be Option?
+    current: Option<Token>,
+    previous: Option<Token>,
+}
+
+#[derive(Debug, PartialEq, PartialOrd)]
+enum Precedence {
+    None,
+    Assignment, // =
+    Or,         // or
+    And,        // and
+    Equality,   // == !=
+    Comparison, // < > <= >=
+    Term,       // + -
+    Factor,     // * /
+    Unary,      // ! -
+    Call,       // . ()
+    Primary,
+}
+
+type ParseFn<T> = fn(&mut Compiler<T>) -> LoxResult<()>;
+
+struct ParseRule<T: Iterator<Item = Token>> {
+    prefix: Option<ParseFn<T>>,
+    infix: Option<ParseFn<T>>,
+    precedence: Precedence,
+}
+
+impl<T: Iterator<Item = Token>> ParseRule<T> {
+    fn new(
+        prefix: Option<ParseFn<T>>,
+        infix: Option<ParseFn<T>>,
+        precedence: Precedence,
+    ) -> Self {
+        ParseRule {
+            prefix,
+            infix,
+            precedence,
+        }
+    }
+}
+
+impl Precedence {
+    // Return the next highest precedence, if there is one.
+    fn next(&self) -> Self {
+        match self {
+            Precedence::None => Precedence::Assignment,
+            Precedence::Assignment => Precedence::Or,
+            Precedence::Or => Precedence::And,
+            Precedence::And => Precedence::Equality,
+            Precedence::Equality => Precedence::Comparison,
+            Precedence::Comparison => Precedence::Term,
+            Precedence::Term => Precedence::Factor,
+            Precedence::Factor => Precedence::Unary,
+            Precedence::Unary => Precedence::Call,
+            Precedence::Call => Precedence::Primary,
+            Precedence::Primary => panic!(
+                "invalid parser state: no higher precedence than Primary"
+            ),
+        }
+    }
+}
+
+fn rule_for<T: Iterator<Item = Token>>(token: &TokenKind) -> ParseRule<T> {
+    match token {
+        TokenKind::LeftParen => {
+            ParseRule::new(Some(Compiler::grouping), None, Precedence::None)
+        }
+
+        TokenKind::Minus => ParseRule::new(
+            Some(Compiler::unary),
+            Some(Compiler::binary),
+            Precedence::Term,
+        ),
+
+        TokenKind::Plus => {
+            ParseRule::new(None, Some(Compiler::binary), Precedence::Term)
+        }
+
+        TokenKind::Slash => {
+            ParseRule::new(None, Some(Compiler::binary), Precedence::Factor)
+        }
+
+        TokenKind::Star => {
+            ParseRule::new(None, Some(Compiler::binary), Precedence::Factor)
+        }
+
+        TokenKind::Number(_) => {
+            ParseRule::new(Some(Compiler::number), None, Precedence::None)
+        }
+
+        _ => ParseRule::new(None, None, Precedence::None),
+    }
+}
+
+impl<T: Iterator<Item = Token>> Compiler<T> {
+    fn compile(&mut self) -> LoxResult<()> {
+        self.advance();
+        self.expression()?;
+        self.consume(
+            &TokenKind::Eof,
+            ErrorKind::ExpectedToken("Expected end of expression"),
+        );
+
+        self.end_compiler()
+    }
+
+    fn advance(&mut self) {
+        self.previous = self.current.take();
+        self.current = self.tokens.next();
+    }
+
+    fn expression(&mut self) -> LoxResult<()> {
+        self.parse_precedence(Precedence::Assignment)
+    }
+
+    fn number(&mut self) -> LoxResult<()> {
+        if let TokenKind::Number(num) = self.previous().kind {
+            self.emit_constant(num);
+            return Ok(());
+        }
+
+        unreachable!("internal parser error: entered number() incorrectly")
+    }
+
+    fn grouping(&mut self) -> LoxResult<()> {
+        self.expression()?;
+        self.consume(
+            &TokenKind::RightParen,
+            ErrorKind::ExpectedToken("Expected ')' after expression"),
+        );
+        Ok(())
+    }
+
+    fn unary(&mut self) -> LoxResult<()> {
+        // TODO(tazjin): Avoid clone
+        let kind = self.previous().kind.clone();
+
+        // Compile the operand
+        self.parse_precedence(Precedence::Unary)?;
+
+        // Emit operator instruction
+        match kind {
+            TokenKind::Minus => self.emit_op(OpCode::OpNegate),
+            _ => unreachable!("only called for unary operator tokens"),
+        }
+
+        Ok(())
+    }
+
+    fn binary(&mut self) -> LoxResult<()> {
+        // Remember the operator
+        let operator = self.previous().kind.clone();
+
+        // Compile the right operand
+        let rule: ParseRule<T> = rule_for(&operator);
+        self.parse_precedence(rule.precedence)?;
+
+        // Emit operator instruction
+        match operator {
+            TokenKind::Minus => self.emit_op(OpCode::OpSubtract),
+            TokenKind::Plus => self.emit_op(OpCode::OpAdd),
+            TokenKind::Star => self.emit_op(OpCode::OpMultiply),
+            TokenKind::Slash => self.emit_op(OpCode::OpDivide),
+            _ => unreachable!("only called for binary operator tokens"),
+        }
+
+        Ok(())
+    }
+
+    fn parse_precedence(&mut self, precedence: Precedence) -> LoxResult<()> {
+        self.advance();
+        let rule: ParseRule<T> = rule_for(&self.previous().kind);
+        let prefix_fn = match rule.prefix {
+            None => unimplemented!("expected expression or something, unclear"),
+            Some(func) => func,
+        };
+
+        prefix_fn(self)?;
+
+        while precedence <= rule_for::<T>(&self.current().kind).precedence {
+            self.advance();
+            match rule_for::<T>(&self.previous().kind).infix {
+                Some(func) => {
+                    func(self)?;
+                }
+                None => {
+                    unreachable!("invalid compiler state: error in parse rules")
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    fn consume(&mut self, expected: &TokenKind, err: ErrorKind) {
+        if (self.current().kind == *expected) {
+            self.advance();
+            return;
+        }
+
+        self.error_at(self.current().line, err);
+    }
+
+    fn current_chunk(&mut self) -> &mut Chunk {
+        &mut self.chunk
+    }
+
+    fn end_compiler(&mut self) -> LoxResult<()> {
+        self.emit_op(OpCode::OpReturn);
+
+        #[cfg(feature = "disassemble")]
+        {
+            chunk::disassemble_chunk(&self.chunk);
+            println!("== compilation finished ==");
+        }
+
+        Ok(())
+    }
+
+    fn emit_op(&mut self, op: OpCode) {
+        let line = self.previous().line;
+        self.current_chunk().add_op(op, line);
+    }
+
+    fn emit_constant(&mut self, val: Value) {
+        let idx = self.chunk.add_constant(val);
+        self.emit_op(OpCode::OpConstant(idx));
+    }
+
+    fn previous(&self) -> &Token {
+        self.previous
+            .as_ref()
+            .expect("invalid internal compiler state: missing previous token")
+    }
+
+    fn current(&self) -> &Token {
+        self.current
+            .as_ref()
+            .expect("invalid internal compiler state: missing current token")
+    }
+
+    fn error_at(&mut self, line: usize, kind: ErrorKind) {
+        if self.panic {
+            return;
+        }
+
+        self.panic = true;
+        self.errors.push(Error { kind, line })
+    }
+}
+
+pub fn compile(code: &str) -> Result<Chunk, Vec<Error>> {
+    let chars = code.chars().collect::<Vec<char>>();
+    let tokens = scanner::scan(&chars).map_err(|errors| {
+        errors.into_iter().map(Into::into).collect::<Vec<Error>>()
+    })?;
+
+    let mut compiler = Compiler {
+        tokens: tokens.into_iter().peekable(),
+        chunk: Default::default(),
+        panic: false,
+        errors: vec![],
+        current: None,
+        previous: None,
+    };
+
+    compiler.compile()?;
+
+    if compiler.errors.is_empty() {
+        Ok(compiler.chunk)
+    } else {
+        Err(compiler.errors)
+    }
+}
diff --git a/users/tazjin/rlox/src/bytecode/compiler/mod.rs b/users/tazjin/rlox/src/bytecode/compiler/mod.rs
deleted file mode 100644
index 5de8fd9f6f06..000000000000
--- a/users/tazjin/rlox/src/bytecode/compiler/mod.rs
+++ /dev/null
@@ -1,287 +0,0 @@
-use super::chunk::{self, Chunk};
-use super::errors::{Error, ErrorKind, LoxResult};
-use super::opcode::OpCode;
-use super::value::Value;
-use crate::scanner::{self, Token, TokenKind};
-
-#[cfg(test)]
-mod tests;
-
-struct Compiler<T: Iterator<Item = Token>> {
-    tokens: T,
-    chunk: Chunk,
-    panic: bool,
-    errors: Vec<Error>,
-
-    // TODO(tazjin): Restructure so that these don't need to be Option?
-    current: Option<Token>,
-    previous: Option<Token>,
-}
-
-#[derive(Debug, PartialEq, PartialOrd)]
-enum Precedence {
-    None,
-    Assignment, // =
-    Or,         // or
-    And,        // and
-    Equality,   // == !=
-    Comparison, // < > <= >=
-    Term,       // + -
-    Factor,     // * /
-    Unary,      // ! -
-    Call,       // . ()
-    Primary,
-}
-
-type ParseFn<T> = fn(&mut Compiler<T>) -> LoxResult<()>;
-
-struct ParseRule<T: Iterator<Item = Token>> {
-    prefix: Option<ParseFn<T>>,
-    infix: Option<ParseFn<T>>,
-    precedence: Precedence,
-}
-
-impl<T: Iterator<Item = Token>> ParseRule<T> {
-    fn new(
-        prefix: Option<ParseFn<T>>,
-        infix: Option<ParseFn<T>>,
-        precedence: Precedence,
-    ) -> Self {
-        ParseRule {
-            prefix,
-            infix,
-            precedence,
-        }
-    }
-}
-
-impl Precedence {
-    // Return the next highest precedence, if there is one.
-    fn next(&self) -> Self {
-        match self {
-            Precedence::None => Precedence::Assignment,
-            Precedence::Assignment => Precedence::Or,
-            Precedence::Or => Precedence::And,
-            Precedence::And => Precedence::Equality,
-            Precedence::Equality => Precedence::Comparison,
-            Precedence::Comparison => Precedence::Term,
-            Precedence::Term => Precedence::Factor,
-            Precedence::Factor => Precedence::Unary,
-            Precedence::Unary => Precedence::Call,
-            Precedence::Call => Precedence::Primary,
-            Precedence::Primary => panic!(
-                "invalid parser state: no higher precedence than Primary"
-            ),
-        }
-    }
-}
-
-fn rule_for<T: Iterator<Item = Token>>(token: &TokenKind) -> ParseRule<T> {
-    match token {
-        TokenKind::LeftParen => {
-            ParseRule::new(Some(Compiler::grouping), None, Precedence::None)
-        }
-
-        TokenKind::Minus => ParseRule::new(
-            Some(Compiler::unary),
-            Some(Compiler::binary),
-            Precedence::Term,
-        ),
-
-        TokenKind::Plus => {
-            ParseRule::new(None, Some(Compiler::binary), Precedence::Term)
-        }
-
-        TokenKind::Slash => {
-            ParseRule::new(None, Some(Compiler::binary), Precedence::Factor)
-        }
-
-        TokenKind::Star => {
-            ParseRule::new(None, Some(Compiler::binary), Precedence::Factor)
-        }
-
-        TokenKind::Number(_) => {
-            ParseRule::new(Some(Compiler::number), None, Precedence::None)
-        }
-
-        _ => ParseRule::new(None, None, Precedence::None),
-    }
-}
-
-impl<T: Iterator<Item = Token>> Compiler<T> {
-    fn compile(&mut self) -> LoxResult<()> {
-        self.advance();
-        self.expression()?;
-        self.consume(
-            &TokenKind::Eof,
-            ErrorKind::ExpectedToken("Expected end of expression"),
-        );
-
-        self.end_compiler()
-    }
-
-    fn advance(&mut self) {
-        self.previous = self.current.take();
-        self.current = self.tokens.next();
-    }
-
-    fn expression(&mut self) -> LoxResult<()> {
-        self.parse_precedence(Precedence::Assignment)
-    }
-
-    fn number(&mut self) -> LoxResult<()> {
-        if let TokenKind::Number(num) = self.previous().kind {
-            self.emit_constant(num);
-            return Ok(());
-        }
-
-        unreachable!("internal parser error: entered number() incorrectly")
-    }
-
-    fn grouping(&mut self) -> LoxResult<()> {
-        self.expression()?;
-        self.consume(
-            &TokenKind::RightParen,
-            ErrorKind::ExpectedToken("Expected ')' after expression"),
-        );
-        Ok(())
-    }
-
-    fn unary(&mut self) -> LoxResult<()> {
-        // TODO(tazjin): Avoid clone
-        let kind = self.previous().kind.clone();
-
-        // Compile the operand
-        self.parse_precedence(Precedence::Unary)?;
-
-        // Emit operator instruction
-        match kind {
-            TokenKind::Minus => self.emit_op(OpCode::OpNegate),
-            _ => unreachable!("only called for unary operator tokens"),
-        }
-
-        Ok(())
-    }
-
-    fn binary(&mut self) -> LoxResult<()> {
-        // Remember the operator
-        let operator = self.previous().kind.clone();
-
-        // Compile the right operand
-        let rule: ParseRule<T> = rule_for(&operator);
-        self.parse_precedence(rule.precedence)?;
-
-        // Emit operator instruction
-        match operator {
-            TokenKind::Minus => self.emit_op(OpCode::OpSubtract),
-            TokenKind::Plus => self.emit_op(OpCode::OpAdd),
-            TokenKind::Star => self.emit_op(OpCode::OpMultiply),
-            TokenKind::Slash => self.emit_op(OpCode::OpDivide),
-            _ => unreachable!("only called for binary operator tokens"),
-        }
-
-        Ok(())
-    }
-
-    fn parse_precedence(&mut self, precedence: Precedence) -> LoxResult<()> {
-        self.advance();
-        let rule: ParseRule<T> = rule_for(&self.previous().kind);
-        let prefix_fn = match rule.prefix {
-            None => unimplemented!("expected expression or something, unclear"),
-            Some(func) => func,
-        };
-
-        prefix_fn(self)?;
-
-        while precedence <= rule_for::<T>(&self.current().kind).precedence {
-            self.advance();
-            match rule_for::<T>(&self.previous().kind).infix {
-                Some(func) => {
-                    func(self)?;
-                }
-                None => {
-                    unreachable!("invalid compiler state: error in parse rules")
-                }
-            }
-        }
-
-        Ok(())
-    }
-
-    fn consume(&mut self, expected: &TokenKind, err: ErrorKind) {
-        if (self.current().kind == *expected) {
-            self.advance();
-            return;
-        }
-
-        self.error_at(self.current().line, err);
-    }
-
-    fn current_chunk(&mut self) -> &mut Chunk {
-        &mut self.chunk
-    }
-
-    fn end_compiler(&mut self) -> LoxResult<()> {
-        self.emit_op(OpCode::OpReturn);
-
-        #[cfg(feature = "disassemble")]
-        chunk::disassemble_chunk(&self.chunk);
-
-        Ok(())
-    }
-
-    fn emit_op(&mut self, op: OpCode) {
-        let line = self.previous().line;
-        self.current_chunk().add_op(op, line);
-    }
-
-    fn emit_constant(&mut self, val: Value) {
-        let idx = self.chunk.add_constant(val);
-        self.emit_op(OpCode::OpConstant(idx));
-    }
-
-    fn previous(&self) -> &Token {
-        self.previous
-            .as_ref()
-            .expect("invalid internal compiler state: missing previous token")
-    }
-
-    fn current(&self) -> &Token {
-        self.current
-            .as_ref()
-            .expect("invalid internal compiler state: missing current token")
-    }
-
-    fn error_at(&mut self, line: usize, kind: ErrorKind) {
-        if self.panic {
-            return;
-        }
-
-        self.panic = true;
-        self.errors.push(Error { kind, line })
-    }
-}
-
-pub fn compile(code: &str) -> Result<Chunk, Vec<Error>> {
-    let chars = code.chars().collect::<Vec<char>>();
-    let tokens = scanner::scan(&chars).map_err(|errors| {
-        errors.into_iter().map(Into::into).collect::<Vec<Error>>()
-    })?;
-
-    let mut compiler = Compiler {
-        tokens: tokens.into_iter().peekable(),
-        chunk: Default::default(),
-        panic: false,
-        errors: vec![],
-        current: None,
-        previous: None,
-    };
-
-    compiler.compile()?;
-
-    if compiler.errors.is_empty() {
-        Ok(compiler.chunk)
-    } else {
-        Err(compiler.errors)
-    }
-}
diff --git a/users/tazjin/rlox/src/bytecode/mod.rs b/users/tazjin/rlox/src/bytecode/mod.rs
index 97316e66aa05..0776225bec91 100644
--- a/users/tazjin/rlox/src/bytecode/mod.rs
+++ b/users/tazjin/rlox/src/bytecode/mod.rs
@@ -28,14 +28,3 @@ impl crate::Lox for Interpreter {
         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/main.rs b/users/tazjin/rlox/src/main.rs
index 2b4e365d4125..2d8cf4f354ea 100644
--- a/users/tazjin/rlox/src/main.rs
+++ b/users/tazjin/rlox/src/main.rs
@@ -11,7 +11,7 @@ mod treewalk;
 /// Trait for making the different interpreters callable in the same
 /// way.
 pub trait Lox {
-    type Value;
+    type Value: std::fmt::Debug;
     type Error: std::fmt::Display;
 
     fn create() -> Self;
@@ -69,9 +69,12 @@ fn run_prompt<I: Lox>() {
 }
 
 fn run<I: Lox>(lox: &mut I, code: String) {
-    if let Err(errors) = lox.interpret(code) {
-        for error in errors {
-            eprintln!("{}", error);
+    match lox.interpret(code) {
+        Ok(result) => println!("=> {:?}", result),
+        Err(errors) => {
+            for error in errors {
+                eprintln!("{}", error);
+            }
         }
     }
 }
-- 
cgit 1.4.1