The component type of a file type must be an assignable type (see Section 6.5). A file that is in inspection mode may be positioned at any component of the sequence or at the end-oJ-Jile position. A file that is in generation mode is always positioned at end-of-file. File values are manipulated by predeclared file-handling procedures and functions (see Section 11). 

The predefined structured type identifier Text represents a special file type in which the sequence is structured as zero or more lines. A line consists of zero or more characters (values oftype Char) followed by a special end-oj-line marker. A variable of type Text is called a textfile. If a nonempty textfile is in inspection mode then there is always an end-of-line immediately preceding the end-of-file position. There are several additional predeclared procedures and functions for manipulating textfiles (see Sections 11.5 and 12). An implementation­ defined set of characters may be prohibited from textfiles, and writing any of these characters to a textfile is implementation-dependent. 

## 6.3. Pointer Types 

A pointer type is distinguished from the structured and simple types in that its set of values is dynamic; i.e., values of a pointer type are created and destroyed during program execution. The set of values of a pointer type always contains a special value, represented by nil. Every other value in the set must be created by a program using the predeclared procedure New (see Section 11.4.2); such values are called identifying values because each one identifies a variable, the so-called identified variahle (see Section 7.3). An identified variable possesses the domain type of the pointer type. An identifying value and its identified variable can be destroyed using the predeclared procedure Dispose (see Section 11.4.2). All identifying values created by a program cease to exist when the program terminates. 

PointerType = "i" DomainType I PointerTypeldentiJier . DomainType = Typeldent~fler . PointerTypeldentiJier = TypeldentifJer . 

## 6.4. Example of a Type Definition Part 

type Natural = o .. Maxint; Color = (Red, Yellow, Green, Blue); 

