Multiline prompt

schala-repl/src/repl/mod.rs

@@ -27,6 +27,12 @@ pub struct Repl {
   options: ReplOptions,
 }
 
+#[derive(Clone)]
+enum PromptStyle {
+  Normal,
+  Multiline
+}
+
 impl Repl {
   pub fn new(initial_states: Vec<Box<dyn ProgrammingLanguageInterface>>) -> Repl {
     use linefeed::Interface;
@@ -62,37 +68,73 @@ impl Repl {
 
   fn handle_repl_loop(&mut self) {
     use linefeed::ReadResult::*;
+    let sigil = self.interpreter_directive_sigil;
 
-    loop {
-      self.update_line_reader();
-      match self.line_reader.read_line() {
-        Err(e) => {
-          println!("readline IO Error: {}", e);
-          break;
-        },
-        Ok(Eof) | Ok(Signal(_)) => break,
-        Ok(Input(ref input)) => {
-          self.line_reader.add_history_unique(input.to_string());
-          match input.chars().nth(0) {
-            Some(ch) if ch == self.interpreter_directive_sigil => match self.handle_interpreter_directive(input) {
-              Some(directive_output) => println!("<> {}", directive_output),
-              None => (),
+    'main: loop {
+      macro_rules! match_or_break {
+        ($line:expr) => {
+          match $line {
+            Err(e) => {
+              println!("readline IO Error: {}", e);
+              break 'main;
             },
-            _ => {
-              for repl_response in self.handle_input(input) {
-                println!("{}", repl_response);
-              }
-            }
+            Ok(Eof) | Ok(Signal(_)) => break 'main,
+            Ok(Input(ref input)) => input,
           }
         }
       }
+      self.update_line_reader();
+      let line = self.line_reader.read_line();
+      let input: &str = match_or_break!(line);
+
+      self.line_reader.add_history_unique(input.to_string());
+      let mut chars = input.chars().peekable();
+      let repl_responses = match chars.nth(0) {
+        Some(ch) if ch == sigil => {
+          if chars.peek() == Some(&'{') {
+            let mut buf = String::new();
+            buf.push_str(input.get(2..).unwrap());
+            'multiline: loop {
+              self.set_prompt(PromptStyle::Multiline);
+              let new_line = self.line_reader.read_line();
+              let new_input = match_or_break!(new_line);
+              if new_input.starts_with(":}") {
+                break 'multiline;
+              } else {
+                buf.push_str(new_input);
+                buf.push_str("\n");
+              }
+            }
+            self.handle_input(&buf)
+          } else {
+            match self.handle_interpreter_directive(input) {
+              Some(directive_output) => println!("<> {}", directive_output),
+              None => (),
+            }
+            continue
+          }
+        },
+        _ => self.handle_input(input)
+      };
+
+      for repl_response in repl_responses.iter() {
+        println!("{}", repl_response);
+      }
     }
   }
 
   fn update_line_reader(&mut self) {
     let tab_complete_handler = TabCompleteHandler::new(self.interpreter_directive_sigil, self.get_directives());
     self.line_reader.set_completer(Arc::new(tab_complete_handler)); //TODO fix this here
-    let prompt_str = format!(">> ");
+    self.set_prompt(PromptStyle::Normal);
+  }
+
+  fn set_prompt(&mut self, prompt_style: PromptStyle) {
+    let prompt_str = match prompt_style {
+      PromptStyle::Normal => ">> ".to_string(),
+      PromptStyle::Multiline => ">| ".to_string(),
+    };
+
     self.line_reader.set_prompt(&prompt_str).unwrap();
   }