From 8edf1b959594a9b338b2ad523412c9483f449bb9 Mon Sep 17 00:00:00 2001
From: Lewis Dale <lewis.dale@fortacode.co.uk>
Date: Mon, 2 Jan 2023 18:41:39 +0000
Subject: [PATCH] Parse escape characters properly

---
 Cargo.toml             |  2 +-
 inputs/hello_world.bas |  2 +-
 src/basic.rs           | 29 +++++++++++++++++++++++++----
 src/main.rs            |  2 +-
 4 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 804b2cb..bcd9f2e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,4 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-nom = "7.1.2"
+nom = { version = "7.1.2", features = ["alloc"] }
diff --git a/inputs/hello_world.bas b/inputs/hello_world.bas
index ac29b12..975eefc 100644
--- a/inputs/hello_world.bas
+++ b/inputs/hello_world.bas
@@ -1 +1 @@
-10 PRINT "Hello, world."
\ No newline at end of file
+10 PRINT "Hello, \"world\"."
\ No newline at end of file
diff --git a/src/basic.rs b/src/basic.rs
index dea8f02..23bb8d6 100644
--- a/src/basic.rs
+++ b/src/basic.rs
@@ -1,6 +1,6 @@
 use nom::{
-    bytes::complete::{tag, take_until},
-    character::complete::u32 as ccu32,
+    bytes::complete::{tag, take_until, escaped},
+    character::{complete::{u32 as ccu32, one_of}, streaming::none_of},
     combinator::map,
     sequence::{delimited, terminated, tuple},
     IResult,
@@ -15,14 +15,19 @@ pub enum Command<'a> {
 }
 
 fn read_string(i: &str) -> IResult<&str, &str> {
-    take_until("\"")(i)
+    // take_until("\"")(i)
+	delimited(
+		tag("\""),
+		escaped(none_of("\\\""), '\\', one_of("\"\\")),
+		tag("\"")
+	)(i)
 }
 
 fn parse_command(i: &str) -> IResult<&str, Command> {
     let (i, (command, _)) = tuple((take_until(" "), tag(" ")))(i)?;
 
     let (i, cmd) = match command {
-        "PRINT" => map(delimited(tag("\""), read_string, tag("\"")), Command::Print)(i)?,
+        "PRINT" => map(read_string, Command::Print)(i)?,
         _ => (i, Command::None),
     };
 
@@ -45,4 +50,20 @@ mod tests {
         let (_, result) = super::parse_line(input).unwrap();
         assert_eq!(expected, result);
     }
+
+	#[test]
+	fn it_reads_a_string() {
+		let input = r#""Hello, \"World\"""#;
+		let (_, output) = super::read_string(input).unwrap();
+		assert_eq!(r#"Hello, \"World\""#, output);
+	}
+
+	#[test]
+	fn it_parses_a_print_command_with_escaped_quotes() {
+		let input = r#"10 PRINT "Hello, \"world\"""#;
+        let expected = (10, super::Command::Print(r#"Hello, \"world\""#));
+
+        let (_, result) = super::parse_line(input).unwrap();
+        assert_eq!(expected, result);
+	}
 }
diff --git a/src/main.rs b/src/main.rs
index 6afda37..c6cd6e9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,7 +8,7 @@ fn main() {
     let (_, (_, command)) = basic::parse_line(lines).unwrap();
     match command {
         basic::Command::Print(input) => {
-            println!("{}", input);
+            println!("{}", input.replace("\\", ""));
         }
         _ => {
             panic!("Command not recognised");