repl now complete

Signed-off-by: Ava Hahn <ava@aidanis.online>

src/bin/main.rs

@@ -0,0 +1,90 @@
+/* relish: versatile lisp shell
+ * Copyright (C) 2021 Aidan Hahn
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+use dirs::home_dir;
+use relish::ast::{eval, lex, Ctr, Seg, SymTable};
+use relish::stdlib::{static_stdlib, dynamic_stdlib};
+use relish::aux::configure;
+use rustyline::error::ReadlineError;
+use rustyline::Editor;
+use std::env;
+
+fn main() {
+    let mut rl = Editor::<()>::new();
+
+    const HIST_FILE: &str = "/.relish_hist";
+    const CONFIG_FILE_DEFAULT: &str = "/.relishrc";
+
+    let home_dir = home_dir().unwrap().to_str().unwrap().to_owned();
+    let hist_file_name = home_dir.clone() + HIST_FILE;
+    let cfg_file_name = home_dir + CONFIG_FILE_DEFAULT;
+
+    if !hist_file_name.is_empty() {
+        rl.load_history(&hist_file_name)
+            .unwrap_or_else(|err: ReadlineError| eprintln!("{}", err));
+    }
+
+    let mut syms = SymTable::new();
+    static_stdlib(&mut syms)
+        .unwrap_or_else(|err: String| eprintln!("{}", err));
+    dynamic_stdlib(&mut syms)
+        .unwrap_or_else(|err: String| eprintln!("{}", err));
+    { // scope the below borrow of syms
+        let cfg_file = env::var("RELISH_CFG_FILE").unwrap_or(cfg_file_name);
+        configure(
+            cfg_file.clone(),
+            &mut syms,
+        ).unwrap_or_else(|err: String| eprintln!("failed to load script {}\n{}",
+                      cfg_file, err));
+    }
+    dynamic_stdlib(&mut syms)
+        .unwrap_or_else(|err: String| eprintln!("{}", err));
+
+    loop {
+        let s = *syms.call_symbol(&"CFG_RELISH_PROMPT".to_string(), &Seg::new(), true)
+            .unwrap_or_else(|err: String| {
+                eprintln!("{}", err);
+                Box::new(Ctr::String("<prompt broken!>".to_string()))
+            });
+        let readline_prompt = s.to_string();
+
+        let user_doc = rl.readline(&readline_prompt);
+        match user_doc {
+            Ok(line) => {
+                rl.add_history_entry(line.as_str());
+                let l = line.as_str().to_owned();
+                match lex(&l) {
+                    Ok(a) => match eval(&a, &mut syms) {
+                        Ok(a) => println!("{}", a),
+                        Err(s) => println!("{}", s),
+                    },
+                    Err(s) => println!("{}", s),
+                }
+            }
+
+            Err(ReadlineError::Interrupted) => break,
+            Err(ReadlineError::Eof) => return,
+            Err(err) => {
+                eprintln!("Prompt error: {:?}", err);
+                break;
+            }
+        }
+    }
+    if !hist_file_name.is_empty() {
+        rl.save_history(&hist_file_name).unwrap();
+    }
+}