feat: implement comparison skeleton

This commit lays out the general idea of how the ComparisonData struct will work. It is expandable and I'm sure we will add more to it as time goes on.

src/common/comparison/number.rs

@@ -0,0 +1,44 @@
+use super::Comparison;
+use crate::common::ValueType;
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize, Debug)]
+pub enum NumberComparison {
+    GreaterThan,
+    LessThan,
+    Equal,
+    NotEqual,
+    GreaterThanOrEqual,
+    LessThanOrEqual,
+}
+
+impl Comparison for NumberComparison {
+    fn evaluate(&self, comp_value: &ValueType, target_value: &ValueType) -> Result<bool, String> {
+        // The prerequisites for all number comparisons is that the target value is Some(number) and the
+        // comparison member points to Some(number) in the student_info.
+        let student_value = match comp_value {
+            ValueType::Number(Some(num)) => num.parse::<i32>().unwrap(),
+            _ => {
+                return Err("Student value is not a number".into());
+            }
+        };
+
+        let target = match target_value {
+            ValueType::Number(Some(num)) => num.parse::<i32>().unwrap(),
+            _ => {
+                return Err("Target value is not a number".into());
+            }
+        };
+
+        let matched = match self {
+            NumberComparison::GreaterThan => student_value > target,
+            NumberComparison::LessThan => student_value < target,
+            NumberComparison::Equal => student_value == target,
+            NumberComparison::NotEqual => student_value != target,
+            NumberComparison::GreaterThanOrEqual => student_value >= target,
+            NumberComparison::LessThanOrEqual => student_value <= target,
+        };
+
+        Ok(matched)
+    }
+}