Param

param use for define external parameters for Navi Stream, external parameters can be passed in when instantiating, thus changing the behavior of the script.

Syntax

param {
    value = 10,

    message = "hello",

    @meta(title = "Limit", range = 50..100)
    limit = 50,

    @meta(title = "Render style", choices = ["line" = "线", "bar" = "柱"])
    render_style = "line",
};

Meta decorator

Use @meta decorator to define the options of this parameter.

Value Range

NOTE: Only number type parameters can specify a range.

The following code specifies that the value of parameter a must be greater than or equal to 50 and less than or equal to 100, default is 50.

param {
    @meta(range = 50..100)
    a = 50,
};

choices

choices is used to specify the available values for a parameter (Like a enum).

The following code specifies that the value of parameter a must be one of 3, 6, 9, default is 3.

param {
    @meta(choices = [3, 6, 9])
    a = 3,
}

You can also specify a name for each choice, which is used to give users a clearer parameter description in the client.

param {
    @meta(choices = ["短" = 3, "中" = 6, "长" = 9])
    a = 6,
}

title

以下语句为 length 参数指定了标题 长度。

param {
    @meta(title = "长度")
    length = 10,
}