Reserved words
│
Deutsch (de) │
English (en) │
français (fr) │
polski (pl) │
русский (ru) │
中文(中国大陆) (zh_CN) │
The keywords of the individual compiler modes are summarized as follows:
- Turbo Pascal mode: the Turbo Pascal keywords are available for you to use
- Delphi mode: the Turbo Pascal and Object Pascal keywords are availabe for you to use
- Free Pascal mode: the Turbo Pascal and Object Pascal keywords are available for you to use
Note: the terms keywords and reserved words are used interchangeably here is this correct?
To do: insert explanation/link to the online Free Pascal manual of what a keyword/reserved word is: e.g. can you name your variables "if" etc
To do: create pages for the keywords if they don't exist yet (e.g. translate from the German version) and link to the online Free Pascal manual section on that keyword in those pages.
Reserved words in Turbo Pascal
The following keywords occur in Turbo Pascal mode:
keyword | description |
---|---|
and | Boolean operator requiring both conditions are true for the result to be true |
array | multiple elements with the same name |
asm | start of code written in assembly language |
begin | start of a block of code |
break | exit a case statemenr |
case | select a particular segement of code to execute based on a value |
const | declare an identifier with a fixed value, or a variable with an initialized value |
constructor | routine used to create an object |
continue | skips an iteration in a for-loop and restart execution at the beginning of the loop |
destructor | routine used to deallocate an object |
div | integer divide operator |
do | used to indicate start of a loop |
downto | used in a for loop to indicate the index variable is decremented |
else | used in if statement to provide an execution path when the if test fails |
end | end of a block of code, a record or certain other constructs] |
false | boolean value indicating a test failed; opposite of true |
file | external data structure, typically stored on disc |
for | loop used to increment or decrement a control variable |
function | define start of a routine that returns a result value |
goto | used to exit a segment of code and jump to another point |
if | test a condition and perform a set of instructions based on the result |
implementation | define the internal routines in unit |
in | identifies elements in a collection |
inline | machine code inserted directly into a routine |
interface | public declarations of routines in a unit |
label | defines the target jump point for a goto |
mod | operator used to return the remainder of an integer division |
nil | pointer value indicating the pointer does not contain a value |
not | boolean operator that negates the result of a test |
object | defines an object construct |
of | defines the characteristics of a variable |
on | |
operator | defines a routine used to implement an operator |
or | boolean operator which allows either of two choices to be used |
packed | indicates the elements of an array are to use less space (this keyword is primarily for compatibility with older programs as packing of array elements is generally automatic) |
procedure | define start of a routine that does not return a result value |
program | defines start of an application. This keyword is usually optional. |
record | group a series of variables under a single name |
repeat | loop through a section of code through an until statement as long as the result of the test is true |
set | group a collection |
shl | operator to shift a value to the left; equivalent to multiplying by a power of 2 |
shr | operator to shift a value to the right; equivalent to dividing by a power of 2 |
string | declares a variable that contains multiple characters |
then | indicates start of code in an if test |
to | indicates a for variable is to be incremented |
true | boolean value indicating a test succeeded; opposite of false |
type | declares kinds of records or new classes of variables |
unit | separately compiled module |
until | indicates end test of a repeat statement |
uses | names units this program or unit refers to |
var | declare variables |
while | test a value and if true, loop through a section of code |
with | reference the internal variables within a record without having to refer to the record itself |
xor | boolean operator used to invert an or test |
Reserved words in Object Pascal
Object Pascal extends the (Turbo) Pascal language with both support for dealing more easily with objects (object orientation) as well as other newer/more advanced concepts (threads, etc).
In addition to the reserved words in Turbo Pascal, the following reserved words are available in Delphi mode as well:
as
class
dispose
except
exit
exports
finalization
finally
inherited
initialization
is
library
new
on
out
property
raise
self
threadvar
try
Reserved words in Free Pascal
The reserved words in Free Pascal mode include:
- Turbo Pascal mode reserved words
- Object Pascal mode reserved words
Modifiers (directives)
The list below is a list of modifiers
Modifiers are not strictly reserved words; however they are used in the same way as reserved words.
See the Free Pascal manual for details.
absolute
abstract
alias
assembler
cdecl
cppdecl
default
export
external
forward
index
local
name
nostackframe
oldfpccall
override
pascal
private
protected
public
published
read
register
reintroduce
safecall
softfloat
stdcall
virtual
write
Unsupported Turbo Pascal modifiers
The reason why these modifiers are not supported is that these modifiers deal with 16 bit code for DOS. In other words, these modifiers have special meaning for 16 bit programming under DOS and Windows 3.x.
As Free Pascal does not support 16 bit code (only 32 and 64 bit), these modifiers are irrelevant in Free Pascal code.
More functionality
Apart from the language features provided by the reserved words/keywords mentioned above, there is a lot of functionality available for the programmer in the various libraries:
- RTL: Run-Time Library, available for all FPC and Lazarus programs
- FCL: Free Component Library: a core set of libraries available for Lazarus programs and usually for FPC (FPC can be compiled without it, but that only happens on purpose for low-memory embedded systems etc)
- FPC Packages: other packages provided by FPC
- Lazarus components: these are Lazarus components that can be dropped on a form and often based on FCL or FPC packages
- Lazarus utility functions: e.g. the fileutil unit.
Apart from the libraries provided by FPC and Lazarus, there are more libraries/components available:
- FPC user-supplied units: see the FPC wiki
- Lazarus CCR: components
- User-supplied code on the internet: see