# Expressions

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## Table of contents

-   [Overview](#overview)
-   [Conversions and casts](#conversions-and-casts)

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## Overview

Expressions are the portions of Carbon syntax that produce values. Because types
in Carbon are values, this includes anywhere that a type is specified.

```
fn Foo(a: i32*) -> i32 {
  return *a;
}
```

Here, the parameter type `i32*`, the return type `i32`, and the operand `*a` of
the `return` statement are all expressions.

## Conversions and casts

When an expression appears in a context in which an expression of a specific
type is expected, [implicit conversions](implicit_conversions.md) are applied to
convert the expression to the target type.

Expressions can also be converted to a specific type using an
[`as` expression](as_expressions.md).

```
fn Bar(n: i32);
fn Baz(n: i64) {
  // OK, same as Bar(n as i32)
  Bar(n);
}
```