Attempts to find and replace all slab recipes using CraftTweaker's ZenScript

slabs.zs

import crafttweaker.recipes.ICraftingRecipe;
import crafttweaker.item.IIngredient;

var slabRecipes = recipes.all;
for recipe in slabRecipes
{
  if (recipe.output.name.toLowerCase has "slab")
  {
    var ingredients = recipe.ingredients1D as IIngredient[];
    var i = 0;
    while ((i < ingredients.length) & (ingredients[i] == null))
    {
      i+=1;
    }
    var input = ingredients[i];
    var ouput = recipe.output;
    output.amount = 4;
    recipes.remove(recipe.output);
    recipes.addShapedMirrored(input.displayName + "-to-" + output.displayName, output, 
      [
        [null,null,null],
        [null,null,null],
        [null,input,input]
      ]
    );
  }
}

Good to know, thanks again