====== Literals ======

Literals are direct representations of variable values.\\


===== Numerical literals  =====

A numerical literal is a decimal number or a number with a certain base (e.g. binary). The underscore "_" character, inserted between the numbers in a numerical literal, is not relevant.\\


|Literal                               ^Example                                  |
|Integer number                        |-12, 0, 123_4, +986                      |
|Floating point number                 |0.0, 0.4560, 3.14159_26                  |
|Floating point number with an exponent|-1.34E-12, -1.34e-12                     |
|Binary number                         |2#1111_1111 (255 decimal)                |
|Octal number                          |8#377 (255 decimal)                      |
|Hexadecimal number                    |16#FF, 16#ff (255 decimal)               |
|Boolean number                        |0, 1, FALSE, TRUE                        |
|Typed number                          |INT#-123, WORD#16#AEF, BOOL#0, BOOL#FALSE|

Note: In FUPLA, literals in other numeric systems than decimal, such as 16#FF, are not supported. All values must be entered as decimal, e.g. 255.

Examples:

<code st-iec>
REAL#+INF, REAL#-INF, LREAL#+INF, LREAL#-INF //literals of special values of real numbers (+- infinity)
REAL#NAN, LREAL#NAN //literals of special values of real numbers (not a number)
</code>

===== Character literals  =====

Character literals are one- or two bytes coded characters. A one-byte literal is a sequence of zero or more characters with a prefix and ending using a single quote character ('). A two-byte literal is a sequence of zero or more characters with a prefix and ending using a single quote character (").

|                              ^Literal                    ^Example    |
|One-byte characters           |Empty string               |''         |
|                              |One character              |'A'        |
|                              |Typed string               |STRING#'OK'|
|Two-byte characters           |Empty string               |""         |
|                              |One character              |"A"        |
|                              |Typed string               |STRING#"OK"|
|Combinations of two characters|Dollar sign                |$$         |
|                              |Apostroph                  |$'         |
|                              |Quotation mark             |$"         |
|                              |Line feed (new line, 16#0A)|$L or $I   |
|                              |Newline (new line)         |$N         |
|                              |Form feed (new page)       |$P         |
|                              |Carriage return (16#0D)    |$R         |
|                              |Tabelator (16#09)          |$T         |

===== Time literals  =====

Time literals represent a duration of an event, or time period elapsed between start and end of an event. Units are days, hours, minutes, seconds, fractions of seconds, and combinations of the above.

^Literal^Description|
|d      |Day        |
|h      |Hour       |
|m      |Minute     |
|s      |Second     |
|ms     |Millisecond|
|us     |Microsecond|
|ns     |Nanosecond |

Examples:

<code st-iec>
T#14ms, TIME#14ms, T#-14ms, LT#14.7s, t#25h15m, TIME#5m_20s_500ms
</code>

===== Time literals of absolute time  =====

^Literal      ^Example                                                                      |
|Date         |DATE#1984-06-25, date#1984-06-25, D#1984-06-25, d#1984-06-25                 |
|Time of day  |TIME_OF_DAY#15:36:55.36, TOD#15:36:55.36                                     |
|Date and time|DATE_AND_TIME#1984-06-25-15:36:55.360227400, DT#1984-06-25-15:36:55.360227400|