#### 1.1.1 Errors

When this manual uses the phrase “an error will be signalled,” it means that Scheme will call `error`, which normally halts execution of the program and prints an error message.

When this manual uses the phrase “it is an error,” it means that the specified action is not valid in Scheme, but the system may or may not signal the error. When this manual says that something “must be,” it means that violating the requirement is an error.