feat: add cli reading

src/eval.rs

@@ -43,7 +43,7 @@ macro_rules! bail {
 
 /// A value in the language. It's the lowest level of representation of a
 /// value, and is used for both the AST and the runtime.
-#[derive(Clone)]
+#[derive(Clone, Default)]
 pub enum Value {
     Int(u64),
     Keyword(Keyword),
@@ -60,9 +60,18 @@ pub enum Value {
     Recur(Vec<Value>),
     Quote(Expr),
     Ptr(*mut ()),
+
+    #[default]
     Nil,
 }
 
+impl Value {
+    /// Reads the values into S-Expressions again
+    pub fn readback(self) -> Term {
+        todo!()
+    }
+}
+
 #[derive(Debug, Hash, Clone, PartialEq, Eq)]
 pub struct Keyword {
     pub text: String,
@@ -76,7 +85,7 @@ impl Keyword {
 }
 
 /// The environment in which evaluation takes place.
-#[derive(Clone)]
+#[derive(Clone, Default)]
 pub struct Environment {
     pub global: Value,
     pub expanded: bool,
@@ -260,7 +269,7 @@ fn apply_expand(apply: crate::Apply, environment: &Environment) -> Result<Value,
 
                 fun.call(environment, arguments).eval_into_result()
             }
-            None | Some(_) => Ok(Value::Apply {
+            _ => Ok(Value::Apply {
                 callee: Value::Keyword(Keyword::from(k.clone())).into(),
                 arguments: apply
                     .spine()?

src/main.rs

@@ -6,6 +6,7 @@ use rustyline::{
     error::ReadlineError, validate::MatchingBracketValidator, Completer, Editor, Helper,
     Highlighter, Hinter, Validator,
 };
+use soft::{eval, Expr, Term};
 
 /// Simple program to greet a person
 #[derive(Parser, Debug)]
@@ -48,6 +49,7 @@ fn get_history_path() -> Option<PathBuf> {
 
 pub fn repl() {
     let mut rl = Editor::new().expect("cannot create repl");
+    let environment = eval::Environment::default();
     let path = get_history_path();
     let h = InputValidator {
         brackets: MatchingBracketValidator::new(),
@@ -65,7 +67,15 @@ pub fn repl() {
         match rl.readline("> ") {
             Ok(line) => {
                 rl.add_history_entry(line.as_str()).unwrap();
-                println!("Line: {}", line)
+                let value = soft::parser::parse_sexpr(&line)
+                    .and_then(|sexpr| Expr::try_from(sexpr).map_err(|error| error.into()))
+                    .and_then(|expr| expr.expand(&environment))
+                    .and_then(|expr| expr.eval(&environment).eval_into_result());
+
+                match value {
+                    Ok(value) => println!("< {}", value.readback()),
+                    Err(error) => eprintln!("- {}", Term::from(error)),
+                }
             }
             Err(ReadlineError::Interrupted) => {
                 println!("Interrupted");

src/parser.rs

@@ -1,6 +1,6 @@
 use std::{iter::Peekable, str::Chars};
 
-use crate::{SrcPos, Term};
+use crate::{SrcPos, Term, Expr, keyword};
 
 pub fn is_identifier_char(c: char) -> bool {
     c != ' ' && c != '\n' && c != '\t' && c != '(' && c != ')' && c != '"' && c != ';'
@@ -36,7 +36,7 @@ impl<'a> Parser<'a> {
         string
     }
 
-    pub fn parse(&mut self) -> Result<Term, String> {
+    pub fn parse(&mut self) -> Result<Term, Expr> {
         let start = self.index;
 
         let result = match self.peek() {
@@ -53,7 +53,7 @@ impl<'a> Parser<'a> {
                 let string = self.accumulate(|c| c != '"');
 
                 if self.bump() != Some('"') {
-                    return Err("expected '\"'".to_string());
+                    return Err(keyword!("parser.error/unexpected-quote"));
                 }
 
                 Ok(Term::String(string))
@@ -83,7 +83,7 @@ impl<'a> Parser<'a> {
                         Some(_) => {
                             terms.push(self.parse()?);
                         }
-                        None => return Err("unexpected end of file".to_string()),
+                        None => return Err(keyword!("parser.error/unexpected-end-of-file")),
                     }
                 }
 
@@ -93,7 +93,7 @@ impl<'a> Parser<'a> {
                 let string = self.accumulate(is_identifier_char);
                 Ok(Term::Identifier(string))
             }
-            None => Err("unexpected end of file".to_string()),
+            None => Err(keyword!("parser.error/unexpected-end-of-file")),
         }?;
 
         Ok(Term::SrcPos(
@@ -106,7 +106,7 @@ impl<'a> Parser<'a> {
     }
 }
 
-pub fn parse_sexpr(string: &str) -> Result<Term, String> {
+pub fn parse_sexpr(string: &str) -> Result<Term, Expr> {
     let mut parser = Parser {
         peekable: string.chars().peekable(),
         string,