0.2.0

Cargo.lock

@@ -10,7 +10,7 @@ checksum = "aacfb566035f8cd02f6ec9247c242f3f9904a0b288ea383abcf4e95df6436a34"
 
 [[package]]
 name = "feval"
-version = "0.1.2"
+version = "0.2.0"
 dependencies = [
  "evalexpr",
 ]

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "feval"
-version = "0.1.2"
+version = "0.2.0"
 edition = "2021"
 description = "clt for fast evaluations"
 readme = "README.md"

src/main.rs

@@ -1,25 +1,44 @@
 use evalexpr;
-use std::env::args;
+use std::{env::args, io::{stdin, stdout, Write}};
 mod tasks;
 use crate::tasks::tasks::all;
 
 fn help() {
     println!(r#"feval: evaluate expressions
-usage: provide exactly one argument (with expression)
+usage: provide exactly one argument (with expression) or no arguments for shell mode.
 example: feval "math::sin(30 * math::pi / 180)""#);
 }
 
+fn main_loop() {
+    print!(">>> ");
+    stdout().flush().unwrap();
+    let mut input = String::new();
+    while stdin().read_line(&mut input).unwrap() != 0 {
+        println!("{}", evalexpr::eval(&input.trim()).unwrap());
+        input.clear();
+        print!(">>> ");
+        stdout().flush().unwrap();
+    }
+}
+
 fn main() {
     let args: Vec<String> = args().collect();
-    if args.len() > 2 {
-        println!("Too many args.");
-        help();
-        return
-    } else if args.len() < 2 {
-        println!("Too few args.");
-        help();
-        return
+    match args.len() {
+        2 => {
+            let expr = all(args[1].clone());
+            println!("{}", evalexpr::eval(&expr).unwrap())
+        },
+        1 => {main_loop()},
+        _ => {
+            if args.len() > 2 {
+                println!("Too many args.");
+                help();
+                return
+            } else if args.len() < 1 {
+                println!("Too few args.");
+                help();
+                return
+            }
+        }
     }
-    let expr = all(args[1].clone());
-    println!("{}", evalexpr::eval(&expr).unwrap())
 }