Various REPL refactoring

schala-repl/src/language.rs

@@ -5,13 +5,7 @@ pub trait ProgrammingLanguageInterface {
     fn language_name(&self) -> String;
     fn source_file_suffix(&self) -> String;
 
-    fn run_computation(&mut self, _request: ComputationRequest) -> ComputationResponse {
-        ComputationResponse {
-            main_output: Err(format!("Computation pipeline not implemented")),
-            global_output_stats: GlobalOutputStats::default(),
-            debug_responses: vec![],
-        }
-    }
+    fn run_computation(&mut self, _request: ComputationRequest) -> ComputationResponse;
 
     fn request_meta(&mut self, _request: LangMetaRequest) -> LangMetaResponse {
         LangMetaResponse::Custom {

schala-repl/src/repl/help.rs

@@ -48,7 +48,6 @@ fn get_directive_from_commands<'a>(
 
 fn global_help(repl: &mut Repl) -> InterpreterDirectiveOutput {
     let mut buf = String::new();
-    let sigil = repl.interpreter_directive_sigil;
 
     writeln!(
         buf,
@@ -63,7 +62,7 @@ fn global_help(repl: &mut Repl) -> InterpreterDirectiveOutput {
         writeln!(
             buf,
             "{}{} - {}",
-            sigil,
+            repl.sigil,
             directive.get_cmd(),
             directive.get_help()
         )

schala-repl/src/repl/mod.rs

@@ -1,5 +1,6 @@
 use std::collections::HashSet;
 use std::sync::Arc;
+use colored::*;
 
 use crate::language::{
     ComputationRequest, LangMetaRequest, LangMetaResponse, ProgrammingLanguageInterface,
@@ -22,7 +23,10 @@ const OPTIONS_SAVE_FILE: &'static str = ".schala_repl";
 type InterpreterDirectiveOutput = Option<String>;
 
 pub struct Repl {
-    pub interpreter_directive_sigil: char,
+    /// If this is the first character typed by a user into the repl, the following
+    /// will be interpreted as a directive to the REPL rather than a command in the 
+    /// running programming language.
+    sigil: char,
     line_reader: ::linefeed::interface::Interface<::linefeed::terminal::DefaultTerminal>,
     language_states: Vec<Box<dyn ProgrammingLanguageInterface>>,
     options: ReplOptions,
@@ -38,10 +42,10 @@ impl Repl {
     pub fn new(initial_states: Vec<Box<dyn ProgrammingLanguageInterface>>) -> Repl {
         use linefeed::Interface;
         let line_reader = Interface::new("schala-repl").unwrap();
-        let interpreter_directive_sigil = ':';
+        let sigil = ':';
 
         Repl {
-            interpreter_directive_sigil,
+            sigil,
             line_reader,
             language_states: initial_states,
             options: ReplOptions::new(),
@@ -49,10 +53,9 @@ impl Repl {
     }
 
     pub fn run_repl(&mut self) {
-        println!("Schala MetaInterpreter version {}", crate::VERSION_STRING);
+        println!("Schala meta-interpeter version {}", crate::VERSION_STRING);
         println!(
-            "Type {}help for help with the REPL",
-            self.interpreter_directive_sigil
+            "Type {} for help with the REPL", format!("{}help", self.sigil).bright_green().bold()
         );
         self.load_options();
         self.handle_repl_loop();
@@ -65,16 +68,15 @@ impl Repl {
             .load_history(HISTORY_SAVE_FILE)
             .unwrap_or(());
         match ReplOptions::load_from_file(OPTIONS_SAVE_FILE) {
-            Ok(options) => {
-                self.options = options;
-            }
-            Err(()) => (),
-        };
+          Ok(options) => {
+            self.options = options;
+          }
+          Err(e) => eprintln!("{}",e)
+        }
     }
 
     fn handle_repl_loop(&mut self) {
         use linefeed::ReadResult::*;
-        let sigil = self.interpreter_directive_sigil;
 
         'main: loop {
             macro_rules! match_or_break {
@@ -96,7 +98,7 @@ impl Repl {
             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 => {
+                Some(ch) if ch == self.sigil => {
                     if chars.peek() == Some(&'{') {
                         let mut buf = String::new();
                         buf.push_str(input.get(2..).unwrap());
@@ -113,8 +115,8 @@ impl Repl {
                         }
                         self.handle_input(&buf)
                     } else {
-                        match self.handle_interpreter_directive(input) {
-                            Some(directive_output) => println!("<> {}", directive_output),
+                        match self.handle_interpreter_directive(input.get(1..).unwrap()) {
+                            Some(directive_output) => println!("{}", directive_output),
                             None => (),
                         }
                         continue;
@@ -131,7 +133,7 @@ impl Repl {
 
     fn update_line_reader(&mut self) {
         let tab_complete_handler =
-            TabCompleteHandler::new(self.interpreter_directive_sigil, self.get_directives());
+            TabCompleteHandler::new(self.sigil, self.get_directives());
         self.line_reader
             .set_completer(Arc::new(tab_complete_handler)); //TODO fix this here
         self.set_prompt(PromptStyle::Normal);
@@ -139,8 +141,8 @@ impl Repl {
 
     fn set_prompt(&mut self, prompt_style: PromptStyle) {
         let prompt_str = match prompt_style {
-            PromptStyle::Normal => ">> ".to_string(),
-            PromptStyle::Multiline => ">| ".to_string(),
+            PromptStyle::Normal => ">> ",
+            PromptStyle::Multiline => ">| ",
         };
 
         self.line_reader.set_prompt(&prompt_str).unwrap();
@@ -154,9 +156,7 @@ impl Repl {
     }
 
     fn handle_interpreter_directive(&mut self, input: &str) -> InterpreterDirectiveOutput {
-        let mut iter = input.chars();
-        iter.next();
-        let arguments: Vec<&str> = iter.as_str().split_whitespace().collect();
+        let arguments: Vec<&str> = input.split_whitespace().collect();
 
         if arguments.len() < 1 {
             return None;

schala-repl/src/repl/repl_options.rs

@@ -2,7 +2,7 @@ use crate::language::DebugAsk;
 
 use std::collections::HashSet;
 use std::fs::File;
-use std::io::{Read, Write};
+use std::io::{self, Read, Write};
 
 #[derive(Serialize, Deserialize)]
 pub struct ReplOptions {
@@ -26,11 +26,11 @@ impl ReplOptions {
             file.write_all(buf.as_bytes())
         });
         if let Err(err) = res {
-            println!("Error saving {} file {}", filename, err);
+            eprintln!("Error saving {} file {}", filename, err);
         }
     }
 
-    pub fn load_from_file(filename: &str) -> Result<ReplOptions, ()> {
+    pub fn load_from_file(filename: &str) -> Result<ReplOptions, io::Error> {
         File::open(filename)
             .and_then(|mut file| {
                 let mut contents = String::new();
@@ -41,6 +41,5 @@ impl ReplOptions {
                 let output: ReplOptions = crate::serde_json::from_str(&contents)?;
                 Ok(output)
             })
-            .map_err(|_| ())
     }
 }