Difference between revisions of "Do while"
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(Removed div styling to reduce width of entry and to maintain continuity and added a few notes to old examples.) |
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| Line 11: | Line 11: | ||
|spec | |spec | ||
|caveats | |caveats | ||
|examples= | |examples=<lsl>//Counts from 1 to 5 | ||
default | default | ||
{ | { | ||
state_entry() | state_entry() | ||
{ | { | ||
integer olf; | integer olf;// Without applied value an integer will be defaulted to zero. | ||
do | do | ||
llSay(0, (string) (++olf)); | llSay(0, (string) (++olf));// Increment before the while condition. | ||
while(olf<5); | while(olf<5); // On the first pass/loop olf = 1 | ||
} | } | ||
}</lsl | }</lsl><lsl>//Counts from 0 to 4 | ||
default | default | ||
{ | { | ||
| Line 29: | Line 28: | ||
integer olf; | integer olf; | ||
do | do | ||
llSay(0, (string)olf); | llSay(0, (string)olf);// olf is still equal to zero. | ||
while((++olf)<5); | while((++olf)<5);// Increment after/during the test. | ||
} | } | ||
}</lsl | }</lsl><lsl>//Counts from 0 to 4 and coments as it loops (block statement demo) | ||
default | default | ||
{ | { | ||
| Line 41: | Line 39: | ||
do | do | ||
{ | { | ||
llSay(0, (string)olf); | llSay(0, (string)olf);// Curly brackets are required since there is more than one looped command. | ||
llSay(0, "looping"); | llSay(0, "looping"); | ||
} | } | ||
while((++olf)<5); | while((++olf)<5); | ||
} | } | ||
}</lsl> | }</lsl><lsl> | ||
<lsl> | |||
//Practical example of where a do/while loop is more immediately useful than a while loop: | //Practical example of where a do/while loop is more immediately useful than a while loop: | ||
//Note that a sensor event always contains input data, so the 'do' always has something to process | //Note that a sensor event always contains input data, so the 'do' always has something to process | ||
| Line 61: | Line 57: | ||
llDialog(llGetOwner(),"Choose an avatar.",gNameList,gDlgChan);//channel is pre-defined when llSensor is triggered | llDialog(llGetOwner(),"Choose an avatar.",gNameList,gDlgChan);//channel is pre-defined when llSensor is triggered | ||
} | } | ||
</lsl | </lsl> | ||
|helpers | |helpers | ||
|also_header | |also_header | ||
Revision as of 03:02, 3 October 2009
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
do loop while (condition);
| • | loop | – | Executes once, then executes condition. | |
| • | condition | – | If condition executes true, it then loops back and executes loop again. |
Any of the statements can be null statements. A do...while loop is slightly faster than a while or for loop, and requires fewer bytes of memory than a while or for loop.
Specification
| Type | Condition |
|---|---|
| integer | True if it is not zero. |
| float | True if it is not zero.[1] |
| string | True if its length is not zero. |
| key | True only if it is a valid key and not NULL_KEY. |
| vector | True if the vector is not ZERO_VECTOR. |
| rotation | True if the rotation is not ZERO_ROTATION. |
| list | True if the length is not zero. Note that correct behavior is only seen with Mono-compiled scripts; LSO-compiled scripts incorrectly resolve to false if the list is non-empty: BUG-230728 |
Examples
<lsl>//Counts from 1 to 5 default {
state_entry()
{
integer olf;// Without applied value an integer will be defaulted to zero.
do
llSay(0, (string) (++olf));// Increment before the while condition.
while(olf<5); // On the first pass/loop olf = 1
}
}</lsl><lsl>//Counts from 0 to 4 default {
state_entry()
{
integer olf;
do
llSay(0, (string)olf);// olf is still equal to zero.
while((++olf)<5);// Increment after/during the test.
}
}</lsl><lsl>//Counts from 0 to 4 and coments as it loops (block statement demo) default {
state_entry()
{
integer olf;
do
{
llSay(0, (string)olf);// Curly brackets are required since there is more than one looped command.
llSay(0, "looping");
}
while((++olf)<5);
}
}</lsl><lsl> //Practical example of where a do/while loop is more immediately useful than a while loop: //Note that a sensor event always contains input data, so the 'do' always has something to process
sensor(integer num)
{ if(num>12)
num=12;
do
{ gNameList += [llGetSubString(llDetectedName(--num),0,23)];//sometimes avatar names are too long for dialog display
gKeyList += [llDetectedKey(num)];//we will dialog select avatar by name, but still need their key
//even if their name has not been truncated above
}while(num>0);
llDialog(llGetOwner(),"Choose an avatar.",gNameList,gDlgChan);//channel is pre-defined when llSensor is triggered
}
</lsl>
Deep Notes
Footnotes
- ^ The OpenSim LSL compiler will not do this implicitly. You will need to use an explicit check.