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/base.rs

@@ -0,0 +1,91 @@
+use super::{
+    Comparison, MapListComparison, NestedListComparison, NumberComparison, NumberListComparison,
+    TextComparison, TextListComparison,
+};
+use crate::common::{ExpandableInfo, ValueType};
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ComparisonData {
+    /// Each comparison will have a unique ID.
+    pub id: String,
+    /// The member from the Student structure to match against.
+    pub member: String,
+    /// The comparison to perform.
+    pub comparison: ComparisonType,
+    /// The value to match against.
+    pub target_value: ValueType,
+    /// The display category for this comparison. Affects where this comparison
+    /// will be displayed in the provider side of the application.
+    pub category: String,
+    /// The text that will be displayed on the provider side.
+    pub display_text: String,
+}
+
+impl ComparisonData {
+    pub fn compare(&self, student_data: &ExpandableInfo) -> Result<bool, String> {
+        let value = student_data.data.get(&self.member).unwrap();
+        self.comparison.evaluate(value, &self.target_value)
+    }
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub enum ComparisonType {
+    Number(NumberComparison),
+    Text(TextComparison),
+    TextList(TextListComparison),
+    NumberList(NumberListComparison),
+    MapList(MapListComparison),
+    NestedList(NestedListComparison),
+}
+
+impl Comparison for ComparisonType {
+    fn evaluate(&self, comp_value: &ValueType, target_value: &ValueType) -> Result<bool, String> {
+        match self {
+            ComparisonType::Number(n) => n.evaluate(comp_value, target_value),
+            ComparisonType::Text(t) => t.evaluate(comp_value, target_value),
+            ComparisonType::NumberList(l) => l.evaluate(comp_value, target_value),
+            ComparisonType::MapList(m) => m.evaluate(comp_value, target_value),
+            ComparisonType::TextList(tl) => tl.evaluate(comp_value, target_value),
+            ComparisonType::NestedList(nl) => nl.evaluate(comp_value, target_value),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::common::comparison::test_utils::create_student_data;
+    use super::*;
+    
+    #[test]
+    fn test_student_data() {
+        let student_data = create_student_data();
+        
+        // Should succeed every time.
+        let text_comp_success = ComparisonData {
+            id: "first_name_success".to_string(),
+            member: "first_name".to_string(),
+            comparison: ComparisonType::Text(TextComparison::Matches),
+            target_value: ValueType::String(Some("John".to_string())),
+            category: "Basic Checks".to_string(),
+            display_text: "First Name is John".to_string(),
+        };
+
+        // Uses an incorrect target_value type.
+        let text_comp_fail = ComparisonData {
+            id: "first_name_fail".to_string(),
+            member: "first_name".to_string(),
+            comparison: ComparisonType::Text(TextComparison::Matches),
+            target_value: ValueType::Number(Some("Jane".to_string())),
+            category: "Basic Checks".to_string(),
+            display_text: "First Name is Jane".to_string(),
+        };
+        
+        let mut result = text_comp_success.compare(&student_data);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+        
+        result = text_comp_fail.compare(&student_data);
+        assert!(result.is_err());
+    }
+}