From 8ab66f1689dade7c346d5a3b51b87194716e03a7 Mon Sep 17 00:00:00 2001
From: Vincent Ambo <mail@tazj.in>
Date: Thu, 31 Dec 2020 13:27:10 +0300
Subject: refactor(tazjin/rlox): Retain interpreter state in REPL

Change-Id: Id60760e241ad0e45871b48e499f58e9831d57316
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2298
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
---
 users/tazjin/rlox/src/interpreter.rs | 31 +++----------------------------
 users/tazjin/rlox/src/main.rs        | 29 +++++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 30 deletions(-)

(limited to 'users/tazjin/rlox/src')

diff --git a/users/tazjin/rlox/src/interpreter.rs b/users/tazjin/rlox/src/interpreter.rs
index 5b03883b6c02..0b936e89d2e1 100644
--- a/users/tazjin/rlox/src/interpreter.rs
+++ b/users/tazjin/rlox/src/interpreter.rs
@@ -1,33 +1,8 @@
-use crate::errors::{report, Error, ErrorKind};
+use crate::errors::{Error, ErrorKind};
 use crate::parser::{self, Declaration, Expr, Literal, Program, Statement};
-use crate::scanner::{self, TokenKind};
+use crate::scanner::TokenKind;
 use std::collections::HashMap;
 
-// Run some Lox code and print it to stdout
-pub fn run(code: &str) {
-    let chars: Vec<char> = code.chars().collect();
-
-    match scanner::scan(&chars) {
-        Ok(tokens) => match parser::parse(tokens) {
-            Ok(program) => {
-                let mut interpreter = Interpreter::default();
-                println!("Program:\n{:?}", program);
-                if let Err(err) = interpreter.interpret(&program) {
-                    println!("Error in program: {:?}", err);
-                }
-            }
-            Err(errors) => report_errors(errors),
-        },
-        Err(errors) => report_errors(errors),
-    }
-}
-
-fn report_errors(errors: Vec<Error>) {
-    for error in errors {
-        report(&error);
-    }
-}
-
 // Tree-walk interpreter
 
 #[derive(Debug, Default)]
@@ -60,7 +35,7 @@ impl Environment {
 }
 
 #[derive(Debug, Default)]
-struct Interpreter {
+pub struct Interpreter {
     globals: Environment,
 }
 
diff --git a/users/tazjin/rlox/src/main.rs b/users/tazjin/rlox/src/main.rs
index 5caac3f1ae03..c56d345862c9 100644
--- a/users/tazjin/rlox/src/main.rs
+++ b/users/tazjin/rlox/src/main.rs
@@ -25,12 +25,14 @@ fn main() {
 // 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");
-    interpreter::run(&contents);
+    let mut lox = interpreter::Interpreter::default();
+    run(&mut lox, &contents);
 }
 
 // Evaluate Lox code interactively in a shitty REPL.
 fn run_prompt() {
     let mut line = String::new();
+    let mut lox = interpreter::Interpreter::default();
 
     loop {
         print!("> ");
@@ -38,7 +40,30 @@ fn run_prompt() {
         io::stdin()
             .read_line(&mut line)
             .expect("failed to read user input");
-        interpreter::run(&line);
+        run(&mut lox, &line);
         line.clear();
     }
 }
+
+fn run(lox: &mut interpreter::Interpreter, code: &str) {
+    let chars: Vec<char> = code.chars().collect();
+
+    match scanner::scan(&chars) {
+        Ok(tokens) => match parser::parse(tokens) {
+            Ok(program) => {
+                println!("Program:\n{:?}", program);
+                if let Err(err) = lox.interpret(&program) {
+                    println!("Error in program: {:?}", err);
+                }
+            }
+            Err(errors) => report_errors(errors),
+        },
+        Err(errors) => report_errors(errors),
+    }
+}
+
+fn report_errors(errors: Vec<errors::Error>) {
+    for error in errors {
+        errors::report(&error);
+    }
+}
-- 
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