Difference between revisions of "Typecast"
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i = (integer) "0123"; // 123 | i = (integer) "0123"; // 123 | ||
i = (integer) "0x12A"; // 298 | i = (integer) "0x12A"; // 298 | ||
i = (integer) " -5 "; // -5; leading whitespace is ignored | |||
i = (integer) "105 degrees here, it is a nice day"; // 105; non-numeric text which follows numeric text is ignored | |||
float f; | float f; | ||
f = (float) "6.2e1"; // 62.0 | f = (float) "6.2e1"; // 62.0 | ||
f = (float) " -16.2°C is seriously cold!"; // -16.2; (float)string also ignores leading whitespace and trailing non-numeric characters | |||
// "6.2e1", "6.2e+1", "6.2E1", "6.2E+1" are all equivalent. | // "6.2e1", "6.2e+1", "6.2E1", "6.2E+1" are all equivalent. | ||
Revision as of 11:46, 23 February 2011
LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
To convert the type of a value a typecast is required. There are two types of typecasting, explicit and implicit. Explicit typecasts must be provided by the programmer, but implicit typecasts are put in place by the compiler. LSL implicitly typecasts strings to keys and integers to floats where the latter type is required but the former is provided.
Supported Typecasts | ||||||||
---|---|---|---|---|---|---|---|---|
To | ||||||||
integer | float | string | key | list | vector | rotation | ||
From | integer | x | x | x | x | |||
float | x | x | x | x | ||||
string | x | x | x | x | x | x | x | |
key | x | x | x | |||||
list | x | x | ||||||
vector | x | x | x | |||||
rotation | x | x | x |
Syntax: (type)value
Converts value to type.
• expression | type | – | variable type | |
• expression | value | – | expression or constant |
If value is a complex expression, it may be beneficial to wrap it in parentheses. (type)(value)
Examples
<lsl> string a = "1.5"; float b = (float)a; integer c = (integer)a;
integer i; i = (integer) 1.23; // 1 i = (integer) -1.23; // -1 i = (integer) "0123"; // 123 i = (integer) "0x12A"; // 298 i = (integer) " -5 "; // -5; leading whitespace is ignored i = (integer) "105 degrees here, it is a nice day"; // 105; non-numeric text which follows numeric text is ignored
float f; f = (float) "6.2e1"; // 62.0 f = (float) " -16.2°C is seriously cold!"; // -16.2; (float)string also ignores leading whitespace and trailing non-numeric characters // "6.2e1", "6.2e+1", "6.2E1", "6.2E+1" are all equivalent.
string s; s = (string) [1, 2.3, "a"]; // "12.300000a" s = (string) <1.0, 2.3, 4.56>; // "<1.00000, 2.30000, 4.56000>"
list l; l = (list) ""; // [""] l = (list) <1.0, 2.3, 4.56>; // ["<1.00000, 2.30000, 4.56000>"]
vector v; v = (vector) "<1.0, 2.3, 4.56>"; // <1.0, 2.3, 4.56> v = (vector) "<1.0, 2.3>"; // ZERO_VECTOR (Due to insufficient value)
rotation r; r = (rotation) "<1.0, 2.3, 4.56, 1.0>"; // <1.0, 2.3, 4.56, 1.0> r = (rotation) "<1.0, 2.3, 4.56>"; // ZERO_ROTATION (Due to insufficient value) </lsl>
Example n°2
<lsl> integer BOOT_TIME; float BOOT_TIME_2; string BOOT_T ; string BOOT_CHAN;
default
{
state_entry() { BOOT_TIME = llGetUnixTime(); BOOT_T = (string)BOOT_TIME; BOOT_TIME_2 = llGetTimeOfDay(); BOOT_CHAN = (string)BOOT_TIME_2; llSetObjectDesc( BOOT_T); llSetText(BOOT_CHAN,<1.0,0.0,0.0>,1.0); }
} </lsl>
Caveats
- The compiler allows explicit typecasting where it is not needed and does not optimize it out. Unnecessary typecasts will bloat code and slow it down.
Notes
- For getting at the elements of a list use the llList2* functions.