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--- introduction_to_lua_programming [2019/01/09 10:07] – akuzmuk
+++ lua:introduction_to_lua_programming [2022/01/17 20:58] (current) – ↷ Links adapted because of a move operation 127.0.0.1
@@ Line 1: / Line 1: @@
+{{ network:lua_logo.png?nolink&100|}}
 ====== Introduction to Lua programming ======
-WebHMI allows you to create custom programs (scripts) in [[https://en.wikipedia.org/wiki/Lua | Lua]] 5.1 language. The scripts are managed in the **Setup -> Scripts** menu item.
+WebHMI allows you to create custom programs (scripts) in [[https://en.wikipedia.org/wiki/Lua | Lua]] 5.1 language.
+The scripts are managed in the **Setup -> Scripts** menu item.
 If you have no experience with Lua language read this tutorial at first  [[ https://gist.github.com/pateltej/bfec90ff449595f12236 | Lua in 15 minutes]].
@@ Line 44: / Line 47: @@
 WebHMI imposes the following restrictions on standard Lua functions and libraries:
-  *such functions and tables are __not available__: require, print, loadfile, dofile, os.execute, os.getenv, os.remove, os.rename, os.tmpname, package , debug.debug, debug.getfenv, debug.getregistry, arg
+  * such functions and tables are __not available__: require, print, loadfile, dofile, os.execute, os.getenv, os.remove, os.rename, os.tmpname, package, debug.debug, debug.getfenv, debug.getregistry, arg
-  *libraries are __not available__: io
+  * libraries are __not available__: io
-In addition to the standard Lua functions, WebHMI also defines additional functions which are decsribed in their respective sections below.
+In addition to the standard Lua functions, WebHMI also defines additional functions which are described in this manual.
-For the convenience of working with registers from Lua programs, each register can be assigned a symbolic name and be accessed from Lua already with this name. This name is specified in the register settings in the **Alias** field:
+For the convenience of working with registers from Lua programs, each register can be assigned a symbolic name and be accessed from Lua with this name. This name is specified in the register settings in the **Script alias** field:
-{{ :alias_in_reg_list2.png?800 |}}
+{{ network:alias_in_reg_list2.png?800 |}}
-In the example above, this name "systemTime" was used in GetReg function to read system time from internal WebHMI register with id = 1.
+In the example above, alias "systemTime" was used in GetReg function to read system time from internal WebHMI register with id = 1.
 An example of a simple script that shows the calls of some WebHMI functions:
@@ Line 75: / Line 78: @@
 </code>
-Despite the fact that the built-in editor checks the syntax of the program, it is not able to detect all the errors that can occur during the execution of the script. In the event that any errors occur during its execution, they will be displayed in communication log (**Maintenance->WebHMI Log**).
+Despite the fact that the built-in editor checks the syntax of the program, it is not able to detect all the errors that can occur during the execution of the script. If any error occurs during script execution, it will be displayed in communication log (**Maintenance->WebHMI Log**).
-For example, once this script will be executed, an error will occur because variable **random** is not declared.
+For example, once this script will be executed, an error will occur because variable **random** was not declared.
 <code lua>
@@ Line 83: / Line 86: @@
   local v1 = GetReg("Drying_Humidity1_Value");
-  v1 = v1+random; -- error is here, without random everything is ok
+  v1 = v1 + random; -- error is here, without random everything is ok
   SetReg("Drying_Humidity1_Value", v1);
@@ Line 100: / Line 103: @@
 </code>
-Here we see that the error occurred while trying to perform an arithmetic operation with an undefined variable (value is **nil**). The error occurred in script number 1, its name was 'Calculate humidity', the error occurred in line number 4 at 12:09:27.047. The variable that caused the error is called 'random'.
+Here we see that the error occurred while trying to perform an arithmetic operation with an undefined variable (value is **nil**). The error occurred in script with id=1, its name was 'Calculate humidity', the error occurred in line number 4 at 12:09:27.047. The variable that caused the error is called 'random'.
-Thus, using this log you can find all runtime errors in your scripts. Also for debugging you can use watch console window, which is available in script editor.
+Thus, using this log you can find all runtime errors in your scripts. Also for debugging you can use watch console window, which is available in [[lua:scripts_editor]].