From 3a25a3d416a30f02cacc1eef4ed16ae7e140ea3a Mon Sep 17 00:00:00 2001
From: PaddiM8 <paddim8@pm.me>
Date: Sat, 13 Jun 2020 21:56:13 +0200
Subject: [PATCH] Added help.

---
 kalk_cli/src/main.rs | 45 +++++++++++++++++++++++++++++---------------
 1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/kalk_cli/src/main.rs b/kalk_cli/src/main.rs
index e521eea..5440718 100644
--- a/kalk_cli/src/main.rs
+++ b/kalk_cli/src/main.rs
@@ -21,22 +21,37 @@ fn main() {
             break;
         };
 
-        if arg == "-i" {
-            let file_name = &args.next().expect("Expected input file."); // The next argument will be the file name.
-            let mut file_content = String::new();
-            File::open(&file_name)
-                .expect("Couldn't find file.")
-                .read_to_string(&mut file_content)
-                .expect("Failed to read input file.");
+        match arg.as_ref() {
+            "-h" | "--help" => {
+                // The indentation... Will have to do something more scalable in the future.
+                println!(
+                    "
+-= kalk help =-\n
+kalk [OPTIONS] [INPUT]
+-h, --help : show this
+-i         : load a file with predefined functions/variables
+                "
+                );
+                return;
+            }
+            "-i" => {
+                let file_name = &args.next().expect("Expected input file."); // The next argument will be the file name.
+                let mut file_content = String::new();
+                File::open(&file_name)
+                    .expect("Couldn't find file.")
+                    .read_to_string(&mut file_content)
+                    .expect("Failed to read input file.");
 
-            // Parse the input file content, resulting in the symbol table being filled out.
-            // Output is not needed here.
-            parser::eval(&mut parser_context, &file_content, 53)
-                .expect("Failed to parse input file.");
-        } else {
-            // Main argument. This is expected to be a maths expression.
-            // After the loop is finished, this will be parsed and outputted.
-            expr_input = Some(arg);
+                // Parse the input file content, resulting in the symbol table being filled out.
+                // Output is not needed here.
+                parser::eval(&mut parser_context, &file_content, 53)
+                    .expect("Failed to parse input file.");
+            }
+            _ => {
+                // Main argument. This is expected to be a maths expression.
+                // After the loop is finished, this will be parsed and outputted.
+                expr_input = Some(arg);
+            }
         }
     }