local | ||||||||||
Type | command | |||||||||
Dictionary | LCS | |||||||||
Library | LiveCode Script | |||||||||
Syntax |
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Summary | Declares one or more local variables and assigns initial values to them. | |||||||||
Introduced | 1.0 | |||||||||
OS | mac, windows, linux, ios, android | |||||||||
Platforms | desktop, server, mobile | |||||||||
Parameters |
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Example |
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Related | Property: preserveVariables, script, explicitVariables Command: constant, do, delete variable, global Function: variableNames, localNames Glossary: property, variable, handler, value, global, local variable, declare, script local variable, command, scope | |||||||||
Description | Use the local command to define a local variable for a handler, or to define a script local variable that is shared between all the handlers in a script. The local declaration is optional. You can use a local variable without declaring it first in the handler. In this case, the local variable can be used only within that handler. The local command can appear anywhere in a handler. However, variable declarations are usually placed at the beginning of a handler. This makes them easier to find and as local variables are created at the point in the script where they are declared it will ensure the variable isn't used before the declaration. You can also use the local command to create a script local variable. Script local variables can be used by any handler in that script, without needing to be declared in the handler itself, and their values are maintained from handler to handler. You create a script local variable by using the local command in a script, outside any handlers in the script. (The difference between a script local variable and a global variable is that a script local variable can only be used in the handlers of one script, while a globalvariable can be used in any handler or script with a global declaration for that variable.) The value of a local variable is retained only while the handler is running. When the handler exits, the value of the local variable is lost. The value of a script local variable is retained between handlers, but is lost when you quit the application, when you close the stack (unless its destroyStack property is false). If variable preservation is turned on, script locals retain their values when the script is re-compiled, unless there is an error in the script. With variable preservation turned off, script locals lose their values when the script is recompiled. It is recommended that naming conventions are followed for variables in Livecode scripts. For handler local variables prefix with a lowercase 't' and for script local variables prefix with a lowercase 's' (as in tMyVariable and sMyVariable). This enables anyone reading the code to identify the scope of a variable when it is used, without having to find where it is declared |