creating a new mutators for if statement conditional

[Brandon Moore]

Good Morning all 

i have created a few custom blocks to generate a custom set of code. I would like to create a mutator block that can generate multiple "AND"/"OR" conditionals in a if statement block(see below screen shot for example)instead of it being set to only 2. 

can someone please assist me if a mutator block is an ideal why to solve this issue or is there an easier / better option available to recommend to me that may solve this problem.

Regards
Brandon

[feni...@google.com]

Hi Brandon,

Yes, a mutator is the correct way to handle this. It sounds like you are already familiar with custom blocks, which is good.

In short, mutators let you add custom serializable state on a block. You'll need to define `domToMutation` and `mutationToDom` functions, which will be called when serializing and deserializing the block. The serialized block will include a <mutation> section. The exact contents are up to you, since you're writing code that both creates and consume it.

Here's an example for the if block:

<block type="controls_if">

  <mutation elseif="1" else="1"></mutation>

</block>

You'll also need to decide how the user adds and removes clauses. The built-in blocks use the UI with the gear and a bubble with a small workspace. This isn't required to use mutators--it is simply one implementation. By contrast, the blocks-plus-minus plugin uses inline plus and minus signs.

I suggest reading through the documentation that I linked and then taking a look at the code for the plus-minus plugin. 

Cheers,

Rachel

[feni...@google.com]

I just remembered--App Inventor does with a mutator and the standard Blockly mutator UI--see the attached image.

Here's the block definition.

Cheers,

Rachel