Difference between revisions of "Os.pullEvent"

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(Added event turtle_inventory for 1.55 update)
(→‎Event types: Added modem_message)
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! rowspan="2" | Name
 
! rowspan="2" | Name
 
! rowspan="2" | Description
 
! rowspan="2" | Description
−
! colspan="3" | Parameters
+
! colspan="5" | Parameters
 
|-
 
|-
−
! 1 !! 2 !! 3
+
! 1 !! 2 !! 3 !! 4 !! 5
 
|-
 
|-
 
! scope="row" | [[char (event)|char]]
 
! scope="row" | [[char (event)|char]]
 
|Fired when text is typed on the keyboard
 
|Fired when text is typed on the keyboard
 
| {{type|string}} the letter typed
 
| {{type|string}} the letter typed
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when a key is pressed on the keyboard
 
|Fired when a key is pressed on the keyboard
 
|{{type|number}} numerical keycode
 
|{{type|number}} numerical keycode
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when a timeout started by [[os.startTimer]]() completes
 
|Fired when a timeout started by [[os.startTimer]]() completes
 
|{{type|number}} Value of the timer as returned by os.startTimer()
 
|{{type|number}} Value of the timer as returned by os.startTimer()
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when a time passed to [[os.setAlarm]]() is reached
 
|Fired when a time passed to [[os.setAlarm]]() is reached
 
|{{type|number}} Value of the alarm as returned by os.setAlarm()
 
|{{type|number}} Value of the alarm as returned by os.setAlarm()
 +
|
 +
|
 
|
 
|
 
|
 
|
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! scope="row" | [[redstone (event)|redstone]]
 
! scope="row" | [[redstone (event)|redstone]]
 
|Fired when the state of any of the redstone inputs change
 
|Fired when the state of any of the redstone inputs change
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when a combination of keys CTRL and T is pressed and held for three seconds.
 
|Fired when a combination of keys CTRL and T is pressed and held for three seconds.
 
You will not normally see this event, as it is handled inside os.pullEvent.
 
You will not normally see this event, as it is handled inside os.pullEvent.
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when a disk is inserted into an adjacent disk drive
 
|Fired when a disk is inserted into an adjacent disk drive
 
|{{type|string}} side
 
|{{type|string}} side
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when a disk is removed from an adjacent disk drive
 
|Fired when a disk is removed from an adjacent disk drive
 
|{{type|string}} side
 
|{{type|string}} side
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when peripheral is attached
 
|Fired when peripheral is attached
 
|{{type|string}} side
 
|{{type|string}} side
 +
|
 +
|
 
|
 
|
 
|
 
|
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|Fired when peripheral is removed
 
|Fired when peripheral is removed
 
|{{type|string}} side
 
|{{type|string}} side
 +
|
 +
|
 
|
 
|
 
|
 
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|Fired when a rednet message is received from the [[Rednet_(API)|rednet API]]
 
|Fired when a rednet message is received from the [[Rednet_(API)|rednet API]]
 
|{{type|number}} senderID
 
|{{type|number}} senderID
 +
|{{type|string}} message
 +
|{{type|number}} distance travelled
 +
|
 +
|
 +
|-
 +
! scope="row" | [[modem_message (event)|modem_message]]
 +
|Fired when a modem message is received from the [[modem]]
 +
|{{type|string}} side
 +
|{{type|number}} frequency
 +
|{{type|number}} replyFrequency
 
|{{type|string}} message
 
|{{type|string}} message
 
|{{type|number}} distance travelled
 
|{{type|number}} distance travelled
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|{{type|string}} url of the site
 
|{{type|string}} url of the site
 
|{{type|table}} text on the site
 
|{{type|table}} text on the site
 +
|
 +
|
 
|
 
|
 
|-
 
|-
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You will not normally see this event as it is handled inside http.get.
 
You will not normally see this event as it is handled inside http.get.
 
|{{type|string}} url of the site
 
|{{type|string}} url of the site
 +
|
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|
 
|
 
|
 
|
 
|
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|{{type|number}} x coordinate
 
|{{type|number}} x coordinate
 
|{{type|number}} y coordinate
 
|{{type|number}} y coordinate
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|
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|
 
|-
 
|-
 
! scope="row" | [[mouse_scroll (event)|mouse_scroll]]
 
! scope="row" | [[mouse_scroll (event)|mouse_scroll]]
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|{{type|number}} x coordinate(in screen chars)
 
|{{type|number}} x coordinate(in screen chars)
 
|{{type|number}} y coordinate(in screen chars)
 
|{{type|number}} y coordinate(in screen chars)
 +
|
 +
|
 
|-
 
|-
 
! scope="row" | [[mouse_drag (event)|mouse_drag]]
 
! scope="row" | [[mouse_drag (event)|mouse_drag]]
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|{{type|number}} x coordinate(in screen chars)
 
|{{type|number}} x coordinate(in screen chars)
 
|{{type|number}} y coordinate(in screen chars)
 
|{{type|number}} y coordinate(in screen chars)
 +
|
 +
|
 
|-
 
|-
 
! scope="row" | [[monitor_touch (event)|monitor_touch]]
 
! scope="row" | [[monitor_touch (event)|monitor_touch]]
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|{{type|number}} x coordinate(in screen chars)
 
|{{type|number}} x coordinate(in screen chars)
 
|{{type|number}} y coordinate(in screen chars)
 
|{{type|number}} y coordinate(in screen chars)
 +
|
 +
|
 
|-
 
|-
 
! scope="row" | [[monitor_resize (event)|monitor_resize]]
 
! scope="row" | [[monitor_resize (event)|monitor_resize]]
 
|Fired when a monitor resizes
 
|Fired when a monitor resizes
 
|{{type|string}} side
 
|{{type|string}} side
 +
|
 +
|
 +
|
 +
|
 
|-
 
|-
 
! scope="row" | [[turtle_inventory (event)|turtle_inventory]]
 
! scope="row" | [[turtle_inventory (event)|turtle_inventory]]
 
|Fired when the inventory on a [[Turtle]] is changed.
 
|Fired when the inventory on a [[Turtle]] is changed.
 
|{{type|string}} side
 
|{{type|string}} side
 +
|
 +
|
 
|
 
|
 
|
 
|

Revision as of 19:43, 18 July 2013


Grid Redstone.png  Function os.pullEvent
Waits (yields) until an event occurs
Syntax os.pullEvent([string filter])
Returns string event, variable parameters(see table below)
Part of ComputerCraft
API OS

Examples

Grid paper.png  Example
The program requires to wait for a keypress to do something:
Code 
function clear()
   term.clear()
   term.setCursorPos (1,1)
end
while true do
   clear()
   print ("Press E to do something.")
   local event, param1 = os.pullEvent ("char") -- limit os.pullEvent to the char event
   if param1 == "e" then -- if the returned value was 'e'
       clear()
       write ("Name: ")
       local name = read()
       print (name)
       break
   else
       clear()
       print ("Wrong button!")
       sleep (1.5) -- I don't like a whole 2 seconds but 1 second is too short
   end
end


Common syntax

event, param1, param2, param3 = os.pullEvent()

Note: This is one of the most commonly used functions that can return multiple values. It works like any other function call (such as "input = read()") except that you can get more than one piece of information back.

How it works

When os.pullEvent() is called, the computer waits until an event occurs. Events can be triggered by several different things, such as a key being pressed or a redstone input changing. They are usually triggered by ComputerCraft itself, when it needs to notify the computer that something happened. They can also be triggered by peripherals, or by your program calling os.queueEvent.

More complicated input, such as "the user typing a line of text," does not correspond to an event. read handles this inside itself by waiting for the user to press a key, then updating the screen, moving the cursor, etc.

Events have a type (which is a string) and 0-5 parameters (which are often but not always strings). No built-in events use more than 3 parameters.

When an event occurs, the event type, followed by the parameters, will be returned. If you have: 

event, button, x, y = os.pullEvent()

and the user clicks the mouse at coordinates 5,4 then:

  • event will be set to "mouse_click" (the event type)
  • button will be set to 0 (the first parameter)
  • x will be set to 5 (the second parameter)
  • y will be set to 4 (the third parameter)

Note that in this example, we didn't specify a filter. If you specify a filter, then all events of different types will be ignored. If the user inserts a disk, instead of clicking the mouse, then event will be "disk", button will be the side the disk drive is on, and x and y will be nil.

If we wanted to only wait for mouse clicks we could use: 

 event, button, x, y = os.pullEvent("mouse_click")

which will ignore any events that are not mouse clicks.

If you assign more variables than necessary, the extra ones will be set to nil. If you assign fewer variables than necessary, the extra parameters will be discarded.

Event types

Name Description Parameters
1 2 3 4 5
char Fired when text is typed on the keyboard string the letter typed
key Fired when a key is pressed on the keyboard number numerical keycode
timer Fired when a timeout started by os.startTimer() completes number Value of the timer as returned by os.startTimer()
alarm Fired when a time passed to os.setAlarm() is reached number Value of the alarm as returned by os.setAlarm()
redstone Fired when the state of any of the redstone inputs change
terminate Fired when a combination of keys CTRL and T is pressed and held for three seconds.

You will not normally see this event, as it is handled inside os.pullEvent.

disk Fired when a disk is inserted into an adjacent disk drive string side
disk_eject Fired when a disk is removed from an adjacent disk drive string side
peripheral Fired when peripheral is attached string side
peripheral_detach Fired when peripheral is removed string side
rednet_message Fired when a rednet message is received from the rednet API number senderID string message number distance travelled
modem_message Fired when a modem message is received from the modem string side number frequency number replyFrequency string message number distance travelled
http_success Fired when an attempt to receive text from / post text on a website is successful.

You will not normally see this event as it is handled inside http.get.

string url of the site table text on the site
http_failure Fired when an attempt to receive text from / post text on a website is unsuccessful

You will not normally see this event as it is handled inside http.get.

string url of the site
mouse_click Fired when a mouse button is pressed number mouse button number x coordinate number y coordinate
mouse_scroll Fired when a mousewheel is scrolled. number scroll direction (-1 for up, 1 for down) number x coordinate(in screen chars) number y coordinate(in screen chars)
mouse_drag Fired when the mouse is moved after clicking. number mouse button number x coordinate(in screen chars) number y coordinate(in screen chars)
monitor_touch Fired when a player right click on an advanced monitor connected. string side number x coordinate(in screen chars) number y coordinate(in screen chars)
monitor_resize Fired when a monitor resizes string side
turtle_inventory Fired when the inventory on a Turtle is changed. string side

Guides

Onionnion's Guide on os.pullEvent()

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