Add comments to code

README.md

@@ -56,7 +56,7 @@ Read [this guide](https://git-send-email.io) for more information.
 
 ## TODO
 
-- [ ] Better documentation
+- [x] Better documentation
 - [ ] Ability to explicitly print math output and assign math output to variables
 - [ ] Add support for comments (should be pretty easy)
 - [ ] Unit testing and CI/CD

src/main.rs

@@ -18,7 +18,6 @@ impl Program {
         
         for opcode in program.split("\n").collect::<Vec<&str>>() {
             let new_op = opcode.to_owned();
-            // new_op = new_op.replace("\n", "");
 
             if new_op.len() != 0 {
                 op_list.push(new_op.to_owned());
@@ -28,21 +27,27 @@ impl Program {
         return Program{ data: op_list, pc: 0, vars: HashMap::new() };
     }
 
+    // Reads the arguments passed to an opcode, and inserts variables where necessary
     fn args_or_vars(&self, arguments: &str) -> String {
-        let mut builder = String::from("");
-        let argument_vec: Vec<char> = arguments.chars().collect();
+        let mut builder = String::from(""); // Empty string that will be rebuilt based on the loop
+        let argument_vec: Vec<char> = arguments.chars().collect(); // Deconstructed arguments
 
+        // Iterate through each char
         for index in 0..argument_vec.len() {
             let current_char = argument_vec[index];
             let str_to_push: String;
 
             if index > 0 {
+                // Only test for the dollar sign if it's not the first character
+                // This is because there can't be anything before the first character, otherwise it's not the first
                 if argument_vec[index-1] == '$' {
+                    // If the previous character is a dollar sign, we can skip this iteration because we know the variable has already been handled
                     continue;
                 }
             }
             
             if current_char == '$' {
+                // If the current char is a $, we know that the next char should be a variable
                 let variable = argument_vec[index+1];
 
                 let key = self.vars.get(&variable);
@@ -52,6 +57,7 @@ impl Program {
                 }
 
             } else {
+                // If there's no variable, then just push the char that was already there
                 str_to_push = current_char.to_string();
             }
 
@@ -65,12 +71,13 @@ impl Program {
     fn add_var(&mut self, arguments: &str) {
         let argument_vec: Vec<char> = arguments.chars().collect();
         let name = argument_vec[0];
-        let value = argument_vec[1..].into_iter().collect::<String>();
+        let value: String = argument_vec[1..].into_iter().collect();
 
         self.vars.insert(name, value);
     }
 
     fn parse(&mut self, instruction: &String) {
+        // Opcode is the first character, arguments are everything after the first char
         let opcode = instruction.chars().collect::<Vec<char>>()[0];
         let arguments = &instruction[1..];
 
@@ -88,11 +95,12 @@ impl Program {
     fn run(&mut self) {
         println!("{}", self);
         while self.pc < self.data.len() {
+            // Grab instruction from op list and parse the instruction
             let instruction = self.data[self.pc].to_owned();
 
             self.parse(&instruction);
 
-            self.pc = self.pc + 1;
+            self.pc += 1;
         }
     }
 }
@@ -104,13 +112,17 @@ impl fmt::Display for Program {
 }
 
 fn main() {
+    // Grab args and a filename
     let args: Vec<String> = env::args().collect();
     if args.len() == 1 {
+        // Args will always have at least 1 argument, which is the name of the executable. 
+        // That's why we're checking index 1, not index 0.
         panic!("You must provide a filename!");
     }
 
     let filename = &args[1];
 
+    // Read contents of the provided file and construct a symbolic Program from it
     let contents = fs::read_to_string(filename).expect("Something went wrong reading the file");
     let mut prog = Program::from_string(contents);
     prog.run();