use toml::{Table, Value};
pub fn merge(base: Value, replacement: Value) -> Value {
match (base, replacement) {
(Value::Array(mut base), Value::Array(mut replacement)) => {
base.append(&mut replacement);
Value::Array(base)
},
(Value::Table(base), Value::Table(replacement)) => {
Value::Table(merge_tables(base, replacement))
},
(_, value) => value,
}
}
fn merge_tables(mut base: Table, replacement: Table) -> Table {
for (key, value) in replacement {
let value = match base.remove(&key) {
Some(base_value) => merge(base_value, value),
None => value,
};
base.insert(key, value);
}
base
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn merge_primitive() {
let base = Value::Table(Table::new());
let replacement = Value::Boolean(true);
assert_eq!(merge(base, replacement.clone()), replacement);
let base = Value::Boolean(false);
let replacement = Value::Boolean(true);
assert_eq!(merge(base, replacement.clone()), replacement);
let base = Value::Integer(0.into());
let replacement = Value::Integer(1.into());
assert_eq!(merge(base, replacement.clone()), replacement);
let base = Value::String(String::new());
let replacement = Value::String(String::from("test"));
assert_eq!(merge(base, replacement.clone()), replacement);
let base = Value::Table(Table::new());
let replacement = Value::Table(Table::new());
assert_eq!(merge(base.clone(), replacement), base);
}
#[test]
fn merge_sequence() {
let base = Value::Array(vec![Value::Table(Table::new())]);
let replacement = Value::Array(vec![Value::Boolean(true)]);
let expected = Value::Array(vec![Value::Table(Table::new()), Value::Boolean(true)]);
assert_eq!(merge(base, replacement), expected);
}
#[test]
fn merge_tables() {
let mut base_table = Table::new();
base_table.insert(String::from("a"), Value::Boolean(true));
base_table.insert(String::from("b"), Value::Boolean(false));
let base = Value::Table(base_table);
let mut replacement_table = Table::new();
replacement_table.insert(String::from("a"), Value::Boolean(true));
replacement_table.insert(String::from("c"), Value::Boolean(false));
let replacement = Value::Table(replacement_table);
let merged = merge(base, replacement);
let mut expected_table = Table::new();
expected_table.insert(String::from("b"), Value::Boolean(false));
expected_table.insert(String::from("a"), Value::Boolean(true));
expected_table.insert(String::from("c"), Value::Boolean(false));
let expected = Value::Table(expected_table);
assert_eq!(merged, expected);
}
}