Difference between revisions of "Lua Programming"

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The TI-Nspire allows, since OS v3.0, programming with the Lua language through a hidden application "TI.ScriptApp".
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The TI-Nspire allows, since OS v3.0, users to run Lua scripts.
  
This page describes how to setup a Lua development environment and documents the currently known Lua functions for the Nspire, and a brief description of how to use the functions.
+
==Prerequisites==
 
 
Note: Neither the ''io'' nor ''os'' libraries are present for the TI-Nspire, which seems to be running a light version of Lua 5.1.4.
 
 
 
Here's a dump of a lot of functions available in the API : [http://adriweb.free.fr/upload/ti/dump.html Link to the dump].
 
  
==Prerequisites==
+
Lua is only supported starting from OS v3.0.1. You can create Lua applications using the built-in script editor in the TI-Nspire computer software or one of the following third-party tools:
  
Lua is only supported starting from OS v3.0.1. Creating Lua scripts is currently not officially supported by TI, you need one of the following third-party tools to convert Lua scripts to TI-Nspire documents:
+
'''For any OS''':
 +
*[https://github.com/ndless-nspire/Luna Luna] (cross-platform) [[https://www.omnimaga.org/news/'luna'-is-here-and-converts-your-lua-files-into-3-0-2-compatible-tns-files/ forum thread]]
 +
'''For OS < 3.0.1''': these tools won't work with the OS 3.0.2 since the format used is now blocked
 
*[http://www.ticalc.org/archives/files/fileinfo/437/43704.html LUAtoTNS.sh] (bash script, works on Linux, Mac OS and Unix, or Windows + Cygwin or Windows + MSYS).
 
*[http://www.ticalc.org/archives/files/fileinfo/437/43704.html LUAtoTNS.sh] (bash script, works on Linux, Mac OS and Unix, or Windows + Cygwin or Windows + MSYS).
 
*[http://www.mirari.fr/KbOD maketns.py] (Python script, cross-platform)
 
*[http://www.mirari.fr/KbOD maketns.py] (Python script, cross-platform)
*[http://www.omnimaga.org/index.php?action=downloads;sa=view;down=651 lua2ti] (Windows + .NET Framework v4.0)
+
*[https://www.omnimaga.org/files/User-Contributed-Calculator-Games-amp-Development-Tools/TI-Nspire-amp-TI-Nspire-CAS/TI-Nspire-Programming-Tools/lua2ti.zip lua2ti] (Windows + .NET Framework v4.0)
*[http://www.omnimaga.org/index.php?action=downloads;sa=view;down=652 lua2ti_linux] (Linux (No longer requires Mono, it is now a native Linux binary!))
+
*[https://www.omnimaga.org/files/User-Contributed-Calculator-Games-amp-Development-Tools/TI-Nspire-amp-TI-Nspire-CAS/TI-Nspire-Programming-Tools/lua2ti_linux.zip lua2ti_linux] (Linux (No longer requires Mono, it is now a native Linux binary!))
You may also want to install Lua [http://www.lua.org/download.html on your computer]: <tt>luac -p</tt> can be used to check the syntax of your script before running it on a TI-Nspire or an emulator.
+
You may also want to install Lua [https://www.lua.org/download.html on your computer]: <tt>luac -p</tt> can be used to check the syntax of your script before running it on a TI-Nspire or an emulator.
 
 
==Standard Library==
 
 
 
*'''_G''' - Global Variable - A global variable (not a function) that holds the global environment (that is, _G._G = _G). Lua itself does not use this variable; changing its value does not affect any environment, nor vice-versa. (Use setfenv to change environments.)  - taken from Lua docs
 
*'''print''' - print (···) - Receives any number of arguments, and prints their values to stdout, using the tostring function to convert them to strings. print is not intended for formatted output, but only as a quick way to show a value, typically for debugging. For formatted output, use string.format.  - taken from Lua Docs
 
*'''tostring''' - tostring (e) - Receives an argument of any type and converts it to a string in a reasonable format. For complete control of how numbers are converted, use string.format. If the metatable of e has a "__tostring" field, then tostring calls the corresponding value with e as argument, and uses the result of the call as its result. - taken from Lua Docs.
 
*'''xpcall''' - xpcall (f, err) - xpcall calls function f in protected mode, using err as the error handler. Any error inside f is not propagated; instead, xpcall catches the error, calls the err function with the original error object, and returns a status code. Its first result is the status code (a Boolean), which is true if the call succeeds without errors. In this case, xpcall also returns all results from the call, after this first result. In case of any error, xpcall returns false plus the result from err. - taken from Lua Docs
 
*'''select''' - select (index, ···)- If index is a number, returns all arguments after argument number index. Otherwise, index must be the string "#", and select returns the total number of extra arguments it received. - Taken from Lua Docs
 
*'''getmetatable''' -
 
*'''unpack''' -
 
 
 
etc.
 
 
 
==Concepts and Basics==
 
 
 
This part will explain you how the Lua actually works inside the OS and help you to figure out what you're doing when you write a script for the TI-Nspire. Before reading this, you have to know all about the Lua basics.
 
 
 
The Lua is an interpreted script language which means that it isn't as fast as ASM/C programs, but is still better than the TI-BASIC.
 
One good thing is that this language is in a complete harmony with the OS with basic events and a powerfull graphic context.
 
First, we have to understand how this works. Basicly the script is launched before the executive engine. This means that we can neither evaluate expressions nor use some of the standard librairy (like math) until the engine is launched. Here is a call summary :
 
 
 
*Launch string library
 
* ...
 
*Open and launch User's Lua script
 
*Launch math library
 
*Launch var API (store, recall, ...)
 
*Launch platform API (window, gc, ...)
 
*...
 
*Link events (pseudo code)
 
while(Exit)
 
------- Some OS routines here
 
 
  ---- Begin of Event link
 
buffer:captureDataFromKeyPad() --  (N) some underground routines to catch events
 
if buffer.charInput ~= "" then --  (N)
 
on.charIn(buffer.charInput)
 
buffer.charInput= "" --  (N)
 
end
 
if buffer.arrowKey ~= "" then --  (N)
 
on.arrowKey(buffer.arrowKey)
 
buffer.arrowKey = "" --  (N)
 
end
 
----- etc ...
 
if platform.window.isInvalidate then
 
platform.gc():purge() --  (N) Empty buffer before starting to draw
 
on.paint(platform.gc())   -- save all the things we have to draw
 
platform:paint()   --  (N) draw all those things
 
platform.window.isInvalidate = false -- say that the window has been drawn
 
end
 
----- End of Event link
 
end
 
''Note : the (N) commented line only indicates the meaning of the routine. Those functions don't really exist.''
 
 
 
Now we can understand how everything is linked, just by a main loop. This helps you to understand that you don't have to code a loop yourself, because the screen wouldn't be refreshed. This also helps to see when the screen gets refreshed. In other words, we cannot use niether '''gc''' nor '''platform.gc()''' (which are the same) in order to draw somthing on the screen if we are outside of '''on.paint()''' (except if your outside function is called within on.paint() ). This also means that we don't need to pass '''gc''' as parameter, because we can rather use '''platform.gc()''' for any functions called within on.paint(). This is exactly what [https://github.com/adriweb/BetterLuaAPI-for-TI-Nspire/blob/master/BetterLuaAPI.lua the BetterLuaAPI library for Nspire] does.
 
 
 
Here is an example of a simple Lua program that displays a message only when a key is pressed (and let the screen blank otherwise).
 
  
function on.paint(gc)
+
==API==
if message then
 
gc:setFont("sansserif", "r", 10) -- initialize font drawing
 
gc:drawString(message, 0, 0, "top") -- display the message at (0, 0) coordinates
 
message = nil -- erase the message
 
timer.start(1) -- start a timer to exit on.paint() but keep in mind that we have to redraw the screen
 
end
 
end
 
 
function on.timer()
 
timer.stop()
 
platform.window:invalidate()
 
end
 
 
function on.charIn(ch)
 
message = "Hello World !" -- store a message
 
platform.window:invalidate() -- force display
 
end
 
  
When you open the document, the script is read once. It initializes and overwrites all the functions and globals with the ones you defined. Thus, '''message''' is nil. Once the '''on.paint()''' event is called, '''message''' is nil, thus, nothing is done. When you press a key that calls '''on.charIn()''' (see below for more information), '''message''' is now "Hello World" and we tell the '''platform''' that the screen has to be refreshed. Then, '''on.paint()''' is called again, '''message''' is not nil then we display it, erase '''message''' and launch a timer. Why is that ? Because if we call '''platform.window:invalidate()''' right there, we won't refresh the screen. Why again ? Just look at the pseudo-code above. We set the window as drawn after each call of on.paint(). Thus a timer is necessary to manually recall '''on.paint()''' and exit the '''on.paint()''' function to draw the screen. When the timer is ended, '''on.timer()''' is called and we refresh the screen. The screen is then redrawn but there is nothing to draw because '''message''' is nil. Thus, the graphic context lets the screen blank.
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The documentation is now maintained in the "[http://wiki.inspired-lua.org Inspired Lua Wiki]".
 +
Please go there in order to have a full detailed documentation based on TI's information.
  
==GC (as in Graphics Context)==
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==XML==
  
Note: You need to add “gc:” before each of these commands in order to use them.
+
===Basic structure===
ex. gc:setAlpha().
 
  
The amount of the screen available to Lua programs is 318 by 212 pixels.
+
<syntaxhighlight lang="xml">
 +
<wdgt
 +
    xmlns:sc="urn:TI.ScriptApp" type="TI.ScriptApp" ver="1.0">
  
*'''begin''' -
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    <sc:mFlags>1024</sc:mFlags>
*'''clipRect''' -
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    <sc:value>8</sc:value>
*'''drawArc'''(x, y, width, height, start angle, finish angle) Note, to draw a circle, use drawArc(x - diameter/2, y - diameter/2, diameter,diameter,0,360) where x and y are the coordinates of the middle.
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    <sc:cry>0</sc:cry>
*'''drawImage''' ? First argument in format “TI.Image”
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    <sc:legal>none</sc:legal>
*'''drawLine'''(xstart, ystart, xend, yend) Draws a line starting at the point (xstart,ystart) and ending at the point (xend, yend)
+
    <sc:schk>false</sc:schk>
*'''drawPolyLine'''(int list1 [,int list2, .., int listN]) Draws a shape from a list contaning successively the x and y coordinates of each point the line have to draw.
 
For example
 
drawPolyLine({0,0, 0,100, 100,100, 100,0, 0,0})
 
and
 
drawRect(0,0,100,100)
 
do the same. If there are multiple argument (which can be 4 elements list to represent lines), each list has to contain an even number of element.
 
*'''drawRect'''(x, y, xwidth, yheight) Draws a rectangle at (x,y) with the “x” side being “xwidth” long and the “y” side being “yheight” long
 
*'''drawString'''(string, x, y, PositionString) PositionString is the string’s anchor point and can be “bottom”, “middle”, or “top”.
 
*'''fillArc'''(x, y, width, height, start angle, finish angle) see drawArc
 
*'''fillPolygon'''(int list1 [,int list2, .., int listN]) see drawPolyLine
 
*'''fillRect'''(x, y, width, height) see drawRect
 
*'''finish''' -
 
*'''getStringHeight'''(string)
 
*'''getStringWidth'''(string)
 
*'''isColorDisplay''' Bool (Read-only) Returns 1 if color, 0 if not.
 
*'''setAlpha''' ≈ transparency ?
 
*'''setColorRGB'''(red, green, blue) Values range from 0 to 255.
 
*'''setFont'''(font, type, size) font {“sansserif”, ..}, type {“b”, “r”, “i”}, size(int)
 
*'''setPen'''(size, smooth) size {“thin”, “medium”, "thick"}, smooth {“smooth”, ..}
 
  
==Platform==
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    <sc:md>
These are mainly read-only. These work by writing "'''platform.'''" in front of them. Example : "'''platform.window:invalidate()'''"
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        <sc:mde name="_VER" prop="134217728">1:1</sc:mde>
*'''apilevel()''' : Returns 1.0.0
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        <sc:mde name="TITLE" prop="2147549184">Hello</sc:mde>
*'''window'''
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        <sc:mde name="TARAL" prop="134217728">2:5</sc:mde>
: *'''width()''' - Returns the width of the window
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    </sc:md>
: *'''height()''' - Returns the height of the window
 
: *'''invalidate()''' - Repaints the window
 
*''' isDeviceModeRendering()''' Returns true or false whether the unit is "rendering" or not
 
*'''gc''' ?
 
*'''isColorDisplay()''' Returns ''true'' if the unit the code is being run on has a color display (-> Nspire CX), and ''false'' otherwise.
 
  
==Cursor==
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    <sc:script version="33882629" id="1">
*'''hide'''() - hides the cursor (mouse pointer)
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-- Lua script, XML encoded
*'''set'''(x,y) - makes the cursor appear at coords (x,y)
+
    </sc:script>
*'''show'''() - Shows the cursor on screen
 
  
==Document==
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    <sc:state>
*'''markChanged'''() - Flag the document as "changed" so the user has to save it after using it.
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        return {} -- Lua save state
 +
    </sc:state>
 +
</wdgt></syntaxhighlight>
  
==Events==
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===Script tags===
  
*'''on.charIn'''(string) is called when the Nspire detects a non arrow key being pressed. ch is the character it detect. If you want to auto start an event in the file linked to key r(like a reset) put on.charIn(“r”) where you want. This Lua program lets you display the value of a valid non arrow key :
+
====sc:script====
  
c = “”
+
{| class="wikitable"
function on.charIn(ch)
+
|-
c = ch
+
! scope="col"| attribute
platform.window:invalidate() -- we force the screen draw
+
! scope="col"| description
end
+
|-
function on.paint(gc)
+
| version
gc:setFont(“sansserif”, “r”, 10)
+
| taral and reqal versions, one byte per digit (for older OSes?)
gc:drawString(c, 0, 0, “top”)
+
|-
end
+
| id
 +
| 1 = normal script, 2 & 3 = Question and Answer
 +
|}
  
*'''on.paint'''(gc) is called when the GUI is painted. 'gc' is the Graphics Context (see above)
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===Script metadata configuration===
*'''on.arrowKey'''(key) is called when an '''arrow key''' from the clickPad/TouchPad is pressed
 
*'''on.enterKey'''() is called when the '''enter''' key is pressed.
 
*'''on.escapeKey'''() is called when the '''escape''' key is pressed.
 
*'''on.tabKey'''() is called when the '''tab''' key is pressed.
 
*'''on.mouseDown'''(x, y) is called when we press the left mouse button. X and Y are the pressed point coordinates.
 
*'''on.mouseUp'''() is called when we release the left mouse button.
 
*'''on.help'''() is called when the combo-key '''Ctrl H''' is pressed.
 
*'''on.clearKey'''() is called when the combo-key '''Ctrl Clear''' is pressed.
 
*'''on.timer'''() is called when the timer has been finished
 
Here an example of using timer to play an animation :
 
x = 1
 
animating = false
 
function on.paint(gc)
 
gc:setFont("sansserif", "r", 10)
 
gc:drawString(tostring(x), 0, 0, "top")
 
if animating then
 
x = x + 1
 
timer.start(0.5)
 
end
 
end
 
 
function on.charIn(ch)
 
animating = not animating -- switch state
 
platform.window:invalidate() -- recall graph engine
 
end
 
 
function on.timer()
 
timer.stop()
 
platform.window:invalidate() -- recall graph engine
 
end
 
*'''on.resize'''()
 
  
==D2Editor==
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{| class="wikitable"
*'''newRichText'''() creates a new RichText object (default values : x, y, width, height = 0)
+
|-
*'''resize'''(width, height)
+
! scope="col"| Name
*'''move'''(x, y)
+
! scope="col"| Prop
*'''setText'''(string)
+
! scope="col"| Description
*'''getText'''() returns the RichText value
+
! scope="col"| Example
*'''setReadOnly'''()
+
|-
*'''setFormattedText''' - ?
+
| TARAL
Example of a valid function using the D2Editor
+
| 134217728
function createRichTextBox
+
| TARget ApiLevel
box = D2Editor.newRichText()
+
| <code><nowiki><sc:mde name="TARAL" prop="134217728">2:2</sc:mde></nowiki></code>
box:move(50, 50)
+
|-
box:resize(50, 50)
+
| REQAL
box:setText("Hello World !")
+
| 134217728
  end
+
| REQuired ApiLevel
It seems that we can edit the RichText box while the document is openned because of the "setReadOnly" function.
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| <code><nowiki><sc:mde name="REQAL" prop="134217728">2:0</sc:mde></nowiki></code>
 +
|-
 +
| _VER
 +
| 134217728
 +
| TNS Version
 +
| <code><nowiki><sc:mde name="_VER" prop="134217728">1:1</sc:mde></nowiki></code>
 +
|-
 +
| TITLE
 +
| 2147549184
 +
| ScriptApp title
 +
| <code><nowiki><sc:mde name="TITLE" prop="2147549184">Hello</sc:mde></nowiki></code>
 +
|-
 +
| -
 +
| 270532608
 +
| Lua meta script
 +
| <code><nowiki><sc:mde name="TEST" prop="270532608">--lua code</sc:mde></nowiki></code>
 +
|-
 +
| BLERQ
 +
| 134217728
 +
| BLE ReQuire - require ble libs
 +
  | <code><nowiki><sc:mde name="BLERQ" prop="134217728">1</sc:mde></nowiki></code>
 +
|-
 +
| _FFunc
 +
| -
 +
| FailMe function (error catching)
 +
| Not known
 +
|-
 +
| _TRACE
 +
| -
 +
| Trace/log?
 +
| Not known
 +
|}

Latest revision as of 14:48, 21 June 2019

The TI-Nspire allows, since OS v3.0, users to run Lua scripts.

Prerequisites

Lua is only supported starting from OS v3.0.1. You can create Lua applications using the built-in script editor in the TI-Nspire computer software or one of the following third-party tools:

For any OS:

For OS < 3.0.1: these tools won't work with the OS 3.0.2 since the format used is now blocked

  • LUAtoTNS.sh (bash script, works on Linux, Mac OS and Unix, or Windows + Cygwin or Windows + MSYS).
  • maketns.py (Python script, cross-platform)
  • lua2ti (Windows + .NET Framework v4.0)
  • lua2ti_linux (Linux (No longer requires Mono, it is now a native Linux binary!))

You may also want to install Lua on your computer: luac -p can be used to check the syntax of your script before running it on a TI-Nspire or an emulator.

API

The documentation is now maintained in the "Inspired Lua Wiki". Please go there in order to have a full detailed documentation based on TI's information.

XML

Basic structure

<wdgt
    xmlns:sc="urn:TI.ScriptApp" type="TI.ScriptApp" ver="1.0">

    <sc:mFlags>1024</sc:mFlags>
    <sc:value>8</sc:value>
    <sc:cry>0</sc:cry>
    <sc:legal>none</sc:legal>
    <sc:schk>false</sc:schk>

    <sc:md>
        <sc:mde name="_VER" prop="134217728">1:1</sc:mde>
        <sc:mde name="TITLE" prop="2147549184">Hello</sc:mde>
        <sc:mde name="TARAL" prop="134217728">2:5</sc:mde>
    </sc:md>

    <sc:script version="33882629" id="1">
	-- Lua script, XML encoded
    </sc:script>

    <sc:state>
        return {} -- Lua save state
    </sc:state>
</wdgt>

Script tags

sc:script

attribute description
version taral and reqal versions, one byte per digit (for older OSes?)
id 1 = normal script, 2 & 3 = Question and Answer

Script metadata configuration

Name Prop Description Example
TARAL 134217728 TARget ApiLevel <sc:mde name="TARAL" prop="134217728">2:2</sc:mde>
REQAL 134217728 REQuired ApiLevel <sc:mde name="REQAL" prop="134217728">2:0</sc:mde>
_VER 134217728 TNS Version <sc:mde name="_VER" prop="134217728">1:1</sc:mde>
TITLE 2147549184 ScriptApp title <sc:mde name="TITLE" prop="2147549184">Hello</sc:mde>
- 270532608 Lua meta script <sc:mde name="TEST" prop="270532608">--lua code</sc:mde>
BLERQ 134217728 BLE ReQuire - require ble libs <sc:mde name="BLERQ" prop="134217728">1</sc:mde>
_FFunc - FailMe function (error catching) Not known
_TRACE - Trace/log? Not known