Original
File types
A file is
an ordered set of elements of the same type. Standard I/O routines use the
predefined TextFile or Text type, which represents a file
containing characters organized into lines. For more information about file input
and output, see Standard
routines and I/O.
To
declare a file type, use the syntax
type fileTypeName = file of type
where fileTypeName is any valid
identifier and type is a fixed-size type. Pointer types whether implicit or
explicit are not allowed, so a file cannot contain dynamic arrays, long
strings, classes, objects, pointers, variants, other files, or structured types
that contain any of these.
For
example,
type
PhoneEntry = record
FirstName, LastName: string[20];
PhoneNumber: string[15];
Listed: Boolean;
end;
PhoneList = file of
PhoneEntry;
declares a file type for recording names
and telephone numbers.
You can
also use the file of ... construction directly in a variable declaration.
For example,
var
List1: file of PhoneEntry;
The word file
by itself indicates an untyped file:
var
DataFile: file;
For more
information, see Untyped
files.
Files are not allowed in arrays or records.
See also
译文
文件类型
文件是相同类型元素的有序集合。标准的I/O例程使用预定义的TextFile或Text类型，它们表示那些包含由字符组织成若干行的文件。有关文件输入和输出的更多信息，见标准例程和I/O。
声明文件类型的语法如下
type fileTypeName = file of type
这里的fileTypeName是任意有效的标识符。隐式指针（如长串、动态数组等）和显式指针（如一般的指针类型、结构指针类型等）都不允许作为文件的元素类型，因此，文件中不能含有动态数组、长串、类、对象、指针、变体、其他文件，或者含有这些类型的结构类型。
例如，
type
PhoneEntry = record
FirstName, LastName: string[20];
PhoneNumber: string[15];
Listed: Boolean;
end;
PhoneList = file of
PhoneEntry;
这里声明了一个用于记录名称和电话号码的文件类型。
也可以在文件变量声明中直接使用file of ... 结构。例如，
var
List1: file of PhoneEntry;
保留字file本身表示一个无类型文件：
var
DataFile: file;
更多信息见无类型文件。
在数组和记录中，文件类型是不允许的。
See also
编者注
对于“在数组和记录中，文件类型是不允许的”这一说法，原文是“Files are not allowed in arrays or records”。编者认为值得商榷。例如，至少编者在Delphi6中已得到验证，下列声明都是合法的，并且可以在语句中正常使用这些数组变量和记录变量：
type
TByteFile = file of Byte;
TStringFile = file of string[40];
TByteFileArr = array [1..100] of TByteFile;
TByteFileFlexibleArr = array of TByteFile;
TStringFileArr = array [1..20] of TStringFile;
TByteFileRec = record
FileName: string;
F: TByteFile;
case Integer of
0: (SizeInBytes: Cardinal);
1: (SizeInKB: Cardinal);
end;
TStringFileRec = record
Path: string;
ShortFileName: string[40];
F: TStringFile;
Size: Cardinal;
end;
var
F1: TByteFile;
F2: TStringFile;
A1: TByteFileArr;
A2: TStringFileArr;
A3: TByteFileFlexibleArr;
R1: TByteFileRec;
R2: TStringFileRec;
begin
SetLength(A3, 1);
AssignFile(F1, 'c:\test1.bin');
AssignFile(F2, 'c:\test2.txt');
AssignFile(A1[1], 'c:\test1.bin');
AssignFile(A2[7], 'c:\test2.txt');
AssignFile(A3[0], 'c:\test2.txt');
AssignFile(R1.F, R1.FileName);
with R2 do AssignFile(F, ShortFileName);
...
end;
因此，可以推定，原文的说法是不准确的（怀疑是Object Pascal较早版本中的特征）。