# Logical and Comparison Expressions

Decodal supports boolean logic over concrete `Bool` values and comparison over concrete scalar values.

```dcdl
{
    is_prod = env == "prod";
    high_port = port > 9000;
    enabled = is_prod && high_port;
    disabled = !enabled;
}
```

## Logical operators

- `!expr` negates a concrete `Bool`.
- `lhs && rhs` returns boolean AND.
- `lhs || rhs` returns boolean OR.

`&&` and `||` short-circuit: the right-hand side is evaluated only when needed.
Logical operands must evaluate to concrete `Bool` values.

## Comparison operators

- `==`
- `!=`
- `<`
- `<=`
- `>`
- `>=`

`==` and `!=` compare concrete scalar values: `String`, `Bool`, `Int`, and `Float`.
`Int` and `Float` can be compared to each other numerically.

Ordering operators `<`, `<=`, `>`, and `>=` compare concrete numeric values only.
They are separate from prefix comparison constraints such as `> 443`.

```dcdl
port = Int & > 443 default 9443;
is_high = port > 9000;
```