BSL:Manual: Difference between revisions

  var int i = 0; # declare a variable named "i" and initialize it to the value zero

When declaring a variable (more on this under {{SectionLink||Variables}}), you must specify the type of data it contains. When declaring a function (more on this under {{SectionLink||Functions}}), you can optionally specify the type of data it accepts and returns. You can choose from "bool" (can be "true" or "false", but see warning under {{SectionLink||bool}}), "int" (can be any whole number), "float" (a value with a decimal point), or "string" (some text).

See {{SectionLink||Functions}} for the meaning of "void". Variables cannot be of type "void".

  var '''bool''' example = true;

  func '''bool''' are_we_there_yet(void)

However, Windows Oni will fail to evaluate bare references to bool variables, and testing indicates the possibility of other bugs existing in Windows Oni's handling of bools. Additionally, Bungie West uses virtually no bool variables in Oni's scripts (though they do use built-in functions that return bool values). Since ints are handled much more reliably, it's recommended to use int for variables instead of bool; the values 1 and 0 can be used to represent "true" and "false".

A 32-bit signed [[wp:Integer|whole number]]; it can be positive, negative or zero, with a maximum value of 2,147,483,647 and a minimum value of -2,147,483,648.

  var '''int''' example = -1000;

  func '''int''' get_enemy_count(void)

Note that the value wraps around, which means that once it passes its maximum or minimum value, it starts over from the other end. For instance, the function...

...will print the positive number "int32: 2147483647" to screen when it runs.

  var '''float''' good_example = 10.5; # returns as "10.500000"

  var '''float''' too_precise = 3.141592653589793; # returns as "3.141593"

Thus, adding a value below the sixth decimal place to a float will have no effect, e.g. 3.000000 + 0.0000001 = 3.000000. Additionally, adding an int value (or a bool value) to a float has no effect:

A sequence of textual characters. BSL does not have any built-in way of performing the string manipulations that you would expect from a scripting language, such as concatenation and trimming, though see below for a simple trimming hack. It also does not provide a reliable method of string comparison (see [[BSL:String comparison|HERE]] for a detailed examination).

  var '''string''' example = "hello";

Trying to give a string a non-textual value (bool/int/float) gives the error "illegal type convertion" (sic). Trying to add two strings with a '+' operator crashes the game, rather than concatenating them as it would in some other languages. Adding a float to a string crashes too. Bools have no effect whatsoever.

Trying to add an int value to a string creates some cool and unexpected results. For instance, adding a number between 5 and 11 removes the first character from the string. A number greater than or equal to 12 removes the first two, and so on. Subtraction does not yield the reverse effect, even if you try it with the maximum int value (in which case Oni crashes). Subtracting numbers can, however, result in printing random strings from Oni's memory, such as BSL function names!