Implement opcode for if-statement

src/main.rs

@@ -4,6 +4,8 @@ use std::fmt;
 use std::fs;
 use std::usize;
 
+use regex::Regex;
+
 mod eval;
 
 struct Program {
@@ -198,6 +200,39 @@ impl Program {
         }
     }
 
+    fn handle_if_statement(&mut self, arguments: String) {
+        let argument_vec: Vec<&str> = arguments.split(":").collect();
+
+        let condition = argument_vec[0];
+        let success = argument_vec[1];
+        let failure = argument_vec[2];
+
+
+        let re = Regex::new(r"(?P<num1>\d+)(?P<operator>==|!=|>|<|>=|<=)(?P<num2>\d+)").unwrap();
+        let caps = re.captures(condition).unwrap();
+        let num1 = &caps["num1"];
+        let operator = &caps["operator"];
+        let num2 = &caps["num2"];
+
+        let meets_condition: bool;
+
+        match operator {
+            "==" => meets_condition = num1 == num2,
+            "!=" => meets_condition = num1 != num2,
+            ">" => meets_condition = num1 > num2,
+            "<" => meets_condition = num1 < num2,
+            ">=" => meets_condition = num1 >= num2,
+            "<=" => meets_condition = num1 <= num2,
+            _ => panic!("SyntaxError: Unknown operator at opcode {}: {}", self.pc, operator)
+        };
+
+        if meets_condition {
+            self.parse(&(success.to_string()));
+        } else {
+            self.parse(&(failure.to_string()));
+        }
+    }
+
     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];
@@ -213,6 +248,7 @@ impl Program {
                 'l' => self.add_var(&arguments),
                 'f' => self.add_func(&arguments),
                 'i' => self.run_external(arguments),
+                '?' => self.handle_if_statement(arguments),
                 _ => panic!("SyntaxError at opcode {}: Unknown opcode {}", self.pc, opcode),
             }
         }