refactor: move arg count

We only use this in the evaluator env, so move it to there.

mute-interpreter/src/env/core.rs

@@ -1,8 +1,7 @@
 use std::borrow::Borrow;
 use std::collections::HashMap;
 
-use super::{NativeFunc, Value};
-use crate::macros::arg_count;
+use super::{macros::arg_count, NativeFunc, Value};
 use crate::Node;
 
 macro_rules! arithmetic {
@@ -69,9 +68,7 @@ pub(super) fn core() -> HashMap<String, Value> {
         (
             "eq?",
             NativeFunc(|args| {
-                if args.len() < 2 {
-                    return Node::Error(format!("expected at least 2 args, got {}", args.len()));
-                }
+                arg_count!(min: 2, args.len());
 
                 args.into_iter()
                     .reduce(|lhs, rhs| match (lhs, rhs) {

mute-interpreter/src/env/io.rs

@@ -1,7 +1,7 @@
 use std::borrow::Borrow;
 use std::collections::HashMap;
 
-use super::{NativeFunc, Value};
+use super::{macros::arg_count, NativeFunc, Value};
 use crate::Node;
 
 pub(super) fn io() -> HashMap<String, Value> {
@@ -39,8 +39,7 @@ pub(super) fn io() -> HashMap<String, Value> {
         (
             "read-file",
             NativeFunc(|args| {
-                // TODO: implement this
-                // arg_count!(1, args.len());
+                arg_count!(1, args.len());
 
                 let val = args[0].borrow();
                 if let Node::String(path) = val {

mute-interpreter/src/env/macros.rs

@@ -1,4 +1,3 @@
-// TODO: argument count checking should happen at parse time, not at runtime
 #[macro_export]
 macro_rules! arg_count {
     ($expected:expr, $given:expr) => {
@@ -7,6 +6,12 @@ macro_rules! arg_count {
         }
     };
 
+    (min: $min:expr, $given:expr) => {
+        if $given < $min {
+            return Node::Error(format!("expected at least {} args, got {}", $min, $given));
+        }
+    };
+
     (modulo: $modulo:expr, $given:expr) => {
         if $given % $modulo != 0 {
             return Node::Error(format!(

mute-interpreter/src/env/mod.rs

@@ -6,6 +6,7 @@ use crate::Node;
 
 mod core;
 mod io;
+mod macros;
 
 #[derive(Debug, Clone)]
 pub struct NativeFunc(fn(args: Vec<Node>) -> Node);

mute-interpreter/src/evaluator.rs

@@ -7,7 +7,6 @@ pub fn eval(env: &Environment, ast: Vec<Node>) -> Result<Vec<Node>> {
     let mut exprs = Vec::new();
 
     for node in ast {
-        dbg!(&node);
         let res = eval_node(env, node)?;
         if let Node::Void = res {
             continue;

mute-interpreter/src/lib.rs

@@ -2,7 +2,6 @@
 mod env;
 mod error;
 mod evaluator;
-mod macros;
 
 pub use env::Environment;
 pub use error::{Error, Result};