Compound Assignments
====================

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Compound assignments are assignments with a [binary operator][operators] attached.

```rust
number += 8;            // number = number + 8

number -= 7;            // number = number - 7

number *= 6;            // number = number * 6

number /= 5;            // number = number / 5

number %= 4;            // number = number % 4

number **= 3;           // number = number ** 3

number <<= 2;           // number = number << 2

number >>= 1;           // number = number >> 1

number &= 0x00ff;       // number = number & 0x00ff;

number |= 0x00ff;       // number = number | 0x00ff;

number ^= 0x00ff;       // number = number ^ 0x00ff;
```


The Flexible `+=`
-----------------

The the `+` and `+=` operators are often [overloaded][function overloading] to perform build-up
operations for different data types.

### Build strings

```rust
let my_str = "abc";

my_str += "ABC";
my_str += 12345;

my_str == "abcABC12345"
```

### Concatenate arrays

```rust
let my_array = [1, 2, 3];

my_array += [4, 5];

my_array == [1, 2, 3, 4, 5];
```

### Concatenate BLOB's

```rust
let my_blob = blob(3, 0x42);

my_blob += blob(5, 0x89);

my_blob.to_string() == "[4242428989898989]";
```

### Mix two object maps together

```rust
let my_obj = #{ a:1, b:2 };

my_obj += #{ c:3, d:4, e:5 };

my_obj == #{ a:1, b:2, c:3, d:4, e:5 };
```

### Add seconds to timestamps

```rust
let now = timestamp();

now += 42.0;

(now - timestamp()).round() == 42.0;
```