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Lesson 1















Automated Internet

Automated Editors

Sample Scripts

Precompiled Functions

System Features

  Help Page - function

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Command function Purpose Creates a function, which is a block of commands, optionally returning a single constant. Aliases function, func, fun, end Syntax A function is declared as follows. function [<options>] <type> <name> [<command>] [<command>] [<command>] ... return [<return_value>] ... end A function is called (invoked) as follows. <name> ( [<var_name> ( <var_value> )] [<var_name> ( <var_value> )] ... ) Options -g Global. If this option is specified, the function being declared is available not only locally (within the current script file and in other scripts it calls), but is also available throughout (globally). Wihout this option, the function is available only locally. Global function must not already be declared anywhere else. Global function can not be declared again (overloaded) anywhere else. Arguments <type> The type of value the function returns. See var for available types. In addition to the available data types, function type can be declared as none, which indicates that the function does not return any value. <name> Name of the function. This name is used when invoking the function. <return_value> A value of type <type>. This can be specified using a constant, variable, expression, function call to another function, inline command, or a combination of these, all resulting in a value of type <type>. When invoking a function, the parameters to the function are passed as <var_name> and <var_value>. <var_name> Name of a variable. If this name is preceeded by $, the variable is assumed to be declared already outside the function. If the name is not preceeded by $, the variable is assumed to be declared inside the function. <var_value> Value of the variable <var_name>. This can be a constant, variable (must have $ sign), expression, inline command, another function or a combination of these. Stream Input Ignored. Stream Output None. Stream Error Any errors from the function, return and end commands are produced here. Description function...end is a programming construct that allows to separate a certain functionality into a separate part of the code. Variables can be declared within a function. These variables remain local to the function and are not available outside. Variable overloading is permitted - variables with the same name as global variables can be declared within a function. If these overloaded variables are used within the function, their local type and value are used, instead of their global type and value. If, in the flow of execution of a function, the end command is encountered before encountering a return command, the default value of <type> will be returned. Restrictions Redirection is not allowed on function, return and end commands. If redirection is specified, it will be ignored. However, commands within the function can have their individual redirections. A function can not call itself recursively. Similarly, two functions can not call each other mutually. Functions must be declared outside of any programming construct, such as if, else, while, for, do. However, the commands within the function themselves can contain these programming constructs. A function can use only variables local to the function, or global variables. Valid Examples function int square # This function calculates the square of the number # passed as variable $num. var int num var int sqr set $sqr = $num*$num return $sqr end The above function calculates the square of an int number. var int i set $i=1 while ($i<=10) do echo square(num($i)) set $i=$i+1 done The above will print squares of numbers 1 thru 10. Invalid Examples var int i ... if ($i<10) function int square ... end Will produce an error. Functions must be declared outside of the if construct. But they can be called inside the if or any other constructs. Consider that a script file script.txt has the following code in it. var int output function int square var int input set $output = $input * $input return $output end When the script file script.txt is executed, it will produce error that variable $output is neither local to the function, nor global. If variable $output were declared with the -g (global) option, it could be used within the function. See Also var return script if while systemvar

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