feat(core): improve printing

- Expression Conversion
- print/println

lispers-core/src/lisp/expression.rs

@@ -198,6 +198,34 @@ impl From<(Expression, Expression)> for Expression {
     }
 }
 
+impl From<i64> for Expression {
+    fn from(value: i64) -> Self {
+        Expression::Integer(value)
+    }
+}
+
+impl From<f64> for Expression {
+    fn from(value: f64) -> Self {
+        Expression::Float(value)
+    }
+}
+
+impl From<String> for Expression {
+    fn from(value: String) -> Self {
+        Expression::String(value)
+    }
+}
+
+impl From<bool> for Expression {
+    fn from(value: bool) -> Self {
+        if value {
+            Expression::True
+        } else {
+            Expression::Nil
+        }
+    }
+}
+
 impl TryFrom<Expression> for i64 {
     type Error = EvalError;
     fn try_from(value: Expression) -> Result<i64, Self::Error> {
@@ -321,7 +349,7 @@ impl Display for Expression {
             Expression::Symbol(s) => write!(f, "{}", s),
             Expression::Integer(i) => write!(f, "{}", i),
             Expression::Float(fl) => write!(f, "{}", fl),
-            Expression::String(s) => write!(f, "\"{}\"", s),
+            Expression::String(s) => write!(f, "{}", s),
             Expression::True => write!(f, "true"),
             Expression::Nil => write!(f, "nil"),
         }

lispers-core/src/lisp/prelude.rs

@@ -213,10 +213,17 @@ pub fn prelude_set(env: &Environment, expr: Expression) -> Result<Expression, Ev
     }
 }
 
+pub fn prelude_println(env: &Environment, expr: Expression) -> Result<Expression, EvalError> {
+    let [e] = expr.try_into()?;
+    let e = eval(env, e)?;
+    println!("{}", e);
+    Ok(e)
+}
+
 pub fn prelude_print(env: &Environment, expr: Expression) -> Result<Expression, EvalError> {
     let [e] = expr.try_into()?;
     let e = eval(env, e)?;
-    println!("Prelude: {}", e);
+    print!("{}", e);
     Ok(e)
 }
 
@@ -270,6 +277,7 @@ pub fn mk_prelude(layer: &mut EnvironmentLayer) {
     layer.set("not".to_string(), Expression::Function(prelude_not));
     layer.set("let".to_string(), Expression::Function(prelude_let));
     layer.set("set".to_string(), Expression::Function(prelude_set));
+    layer.set("println".to_string(), Expression::Function(prelude_println));
     layer.set("print".to_string(), Expression::Function(prelude_print));
     layer.set("cons".to_string(), Expression::Function(prelude_cons));
     layer.set("car".to_string(), Expression::Function(prelude_car));