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@@ -316,6 +316,61 @@ wait Wait for user input before continuing. Useful mostly for debugging or test development. +### Functions + +When calling a function, parameters are usually passed using argument keywords +(in the case of built-in commands, those keywords are typically prepositions +like `on`, `from`, etc.), and apart from those, there can be at most one +parameter passed without a keyword. This is done in order to avoid the need to +remember parameter order and to make the behavior of each call as clear as +possible, even without looking up the documentation. + +To make the syntax unambiguous, the keywordless parameter can be passed as the +last parameter, as a literal (number, string, etc.), or using parentheses. So this is ok: + +``` +expect /something/ from p +``` + +but if the regular expression is stored in a variable, the parameter needs to move to the end: +``` +let re = /something/ +expect from p re +``` + +or be enclosed in parentheses: +``` +expect (re) from p +``` +or in a literal: +``` +expect /$re/ from p +``` + +### Defining functions + +Custom functions can be defined on the top level using `def` keyword, and with +the parameters either followed by `=` sign to return a value: +``` +def twice x = 2 * x +``` + +or followed by `:` to define test block: +``` +def greet p: + send "hello" to p + expect /hi/ from p +``` + +Those then can be invoked elsewhere: +``` +test: + spawn as p + greet p +``` + + + Optional dependencies --------------------- |