Mixins are a simple way of preventing yourself from repeating the same pattern over and over in your patches. They are quite simple to declare, and to use.
Declaring a mixin
Mixins are declared using the @mixin top level state followed by the name of the mixin, and then an (, an optional list of mixin parameters, followed by a ) and then a { and then any amount of Selection Actions. then a }.
For a very simple mixin declaration with no parameters:
@mixin scale-mass-by-two() {
mass *: 2;
}
Mixin Parameters
As mentioned before, mixins can have parameters, they are a comma separated list of $parameter-name, with optional default values, which then make them of the form $parameter-name:[default-value-expression].
Here are a few examples of the above:
// Mixin with one parameter
@mixin scale-mass-by($N) {
mass *: $N;
}
// Mixin with one default parameter
@mixin scale-max-temp-by($N:2) {
maxTemp *: $N;
}
// Mixin with 2 parameters, one default
@mixin scale-mass-by-and-max-temp-by($mass-scale,$temp-scale:$mass-scale) {
mass: *$mass-scale;
maxTemp *: $temp-scale;
}
Slotted Mixins
Sometimes you may want your mixin to take more than just values as arguments, and this is where "Slotted Mixins" come in these can take a set of selection actions as a "parameter", and this set can be executed using the @mixin-slot keyword
// Unslotted mixin
@mixin ps-pam-override() {
PAMModuleVisualsOverride +: [
{
PartComponentModuleName: PartComponentModule_PartSwitch,
ModuleDisplayName: "VSwift/PartSwitch",
ShowHeader: true,
ShowFooter: false
}
];
}
// Slotted mixin
@mixin part-switch() {
+Module_PartSwitch {
+Data_PartSwitch {
@mixin-slot // Whatever selection actions are passed will be executed when this action is executed
}
}
@include ps-pam-override()
}
Using Mixins
Now that you have declared mixins, you need to be able to include them into your selection blocks, using the following construct: @include mixin-name([parameters]), the parameters are a comma separated list of values corresponding to the parameters defined in the mixin declaration, but they can also be named in the form of $parameter-name:[passed-value].
What including a mixin does, is essentially copy and paste all the selection actions declared within the mixin into your selection block in a sub environment (as in similar to a * {...} selection block), and replace the parameters in the mixin with the values you passed.
Here are a few examples of including the mixins defined above:
:parts #wheel_0v_rover {
@include scale-mass-by-two() // Scale the mass by 2 using the parameterless mixin
@include scale-max-temp-by() // Scale the max temp by 2, as the default value of $N is 2
}
:parts #wheel_1v_rover {
@include scale-mass-by(2) // Scale the mass by 2 using the parameterized mixin
@include scale-max-temp-by($N:2) // Scale the max temp by 2, and explicitly name the argument
}
:parts #wheel_2v_rover {
@include scale-mass-by-and-max-temp-by(2) // Scale the mass by 2, and the max temp by 2 as the $temp-scale is equal to $mass-scale by default
}
:parts #wheel_2v_rover_rugged {
@include scale-mass-by-and-max-temp-by(2,4) // Scale the mass by 2, and the max temp by 4
}
:parts #wheel_3v_rover {
@include scale-mass-by-and-max-temp-by($temp-scale:4,$mass-scale:2) // Scale the mass by 2, and the max temp by 4, passing the parameters in reverse
}
Using Slotted Mixins
To use slotted mixins, the process is the same as a normal @include process, but after the (...) you start a selection block using { and then putting the set of actions you want to be put into the slot and closing it with a }.
@use "VSwift:*";
:parts #KLSS_water_tank_2v_1x2 {
@include part-switch() { // Everything in the `{}` will be executed when the mixin hits a `@mixin-slot` keyword
+Pipes {
+No {
Transforms: [];
}
+Yes {
Transforms: [
Pipes,
"Sub Hatch"
];
}
}
+Crossbars {
+No {
Transforms: [];
}
+Yes {
Transforms: [
"Cross Armature"
];
}
}
}
}