Unquote the text.

src/parser/sexp.rs

@@ -32,6 +32,45 @@ pub struct TextWithProperties<'s> {
     pub properties: Vec<Token<'s>>,
 }
 
+impl<'s> TextWithProperties<'s> {
+    pub fn unquote(&self) -> Result<String, Box<dyn std::error::Error>> {
+        let mut out = String::with_capacity(self.text.len());
+        if !self.text.starts_with(r#"""#) {
+            return Err("Quoted text does not start with quote.".into());
+        }
+        if !self.text.ends_with(r#"""#) {
+            return Err("Quoted text does not end with quote.".into());
+        }
+        let interior_text = &self.text[1..(self.text.len() - 1)];
+        let mut state = ParseState::Normal;
+        for current_char in interior_text.chars().into_iter() {
+            state = match (state, current_char) {
+                (ParseState::Normal, '\\') => ParseState::Escape,
+                (ParseState::Normal, _) => {
+                    out.push(current_char);
+                    ParseState::Normal
+                }
+                (ParseState::Escape, 'n') => {
+                    out.push('\n');
+                    ParseState::Normal
+                }
+                (ParseState::Escape, '\\') => {
+                    out.push('\\');
+                    ParseState::Normal
+                }
+                _ => todo!(),
+            };
+        }
+
+        Ok(out)
+    }
+}
+
+enum ParseState {
+    Normal,
+    Escape,
+}
+
 impl<'s> Token<'s> {
     pub fn as_list<'p>(&'p self) -> Result<&'p Vec<Token<'s>>, Box<dyn std::error::Error>> {
         Ok(match self {