Extract IO operations to own module

1 files changed, 47 insertions, 0 deletions

diff --git a/rust/src/io.rs b/rust/src/io.rs
new file mode 100644
index 0000000..33d8c4e
--- /dev/null
+++ b/rust/src/io.rs
@@ -0,0 +1,47 @@
+use std::{
+    fs::read_to_string,
+    io::{BufRead, BufReader, Read, Write},
+};
+
+use crate::{
+    ast::Value,
+    lambda::{eval, eval_all, Environment},
+    parser::parse,
+};
+
+pub fn eval_file(file_name: &str) -> String {
+    let content = read_to_string(file_name).unwrap();
+    let values = parse(&content.to_string());
+    eval_all(&values)
+        .iter()
+        .map(|v| v.to_string())
+        .collect::<Vec<String>>()
+        .join(" ")
+}
+
+pub fn repl<I: Read, O: Write>(inp: &mut I, outp: &mut O) {
+    let mut env = Environment::new();
+    let mut reader = BufReader::new(inp);
+    loop {
+        let mut input = String::new();
+        write!(outp, "> ").unwrap();
+        outp.flush().unwrap();
+        match reader.read_line(&mut input) {
+            Ok(0) => break,
+            Ok(_) => (),
+            Err(e) => {
+                writeln!(outp, "{}", e).unwrap();
+                break;
+            }
+        }
+        let values = parse(&input);
+        let results = values
+            .iter()
+            .map(|v| eval(v, &mut env))
+            .collect::<Vec<Value>>();
+        for result in results {
+            writeln!(outp, "{}", result).unwrap();
+            outp.flush().unwrap();
+        }
+    }
+}