UPDATE: Adds a bunch of documentation and examples

base/examples/hello_world.rs

@@ -0,0 +1,19 @@
+use ironcalc_base::{cell::CellValue, model::Model};
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut model = Model::new_empty("hello-world", "en", "UTC")?;
+    // A1
+    model.set_user_input(0, 1, 1, "Hello".to_string());
+    // B1
+    model.set_user_input(0, 1, 2, "world!".to_string());
+    // C1
+    model.set_user_input(0, 1, 3, "=CONCAT(A1, \" \", B1".to_string());
+    // evaluates
+    model.evaluate();
+
+    assert_eq!(
+        model.get_cell_value_by_index(0, 1, 3),
+        Ok(CellValue::String("Hello world!".to_string()))
+    );
+    Ok(())
+}