carbon-lang/docs/design/expressions

Expressions

Table of contents

• Overview
• Conversions and casts

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 are applied to convert the expression to the target type.

Expressions can also be converted to a specific type using an as expression.

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