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Lists in every editor

Much of what a script handles comes in lists: the points of a curve, the faces of a solid, the copies of a part. Two different things can happen to a list, and it helps to tell them apart.

A list as one value​

Some functions want a whole list. bitbybit.occt.shapes.wire.interpolatePoints takes a list of points and makes one curve through all of them; bitbybit.occt.booleans.difference takes one shape and a list of shapes to cut from it. The list travels as a single value, exactly like a number would.

Here bitbybit.point.spiral makes a list of two hundred points, and one curve is made through them:

Bitbybit Platform

A spiral of points, one curve through them in Rete

rete logoRete
Script Source (rete)
{
  "id": "rete-v2-json",
  "nodes": {
    "spiral": {
      "id": "spiral",
      "name": "bitbybit.point.spiral",
      "customName": "spiral",
      "async": false,
      "drawable": true,
      "data": {
        "genericNodeData": {
          "hide": false,
          "oneOnOne": false,
          "flatten": 0,
          "forceExecution": false
        },
        "phi": 0.9,
        "numberPoints": 200,
        "widening": 3,
        "radius": 6,
        "factor": 1
      },
      "inputs": {},
      "position": [
        40,
        40
      ]
    },
    "curve": {
      "id": "curve",
      "name": "bitbybit.occt.shapes.wire.interpolatePoints",
      "customName": "interpolate points",
      "async": true,
      "drawable": true,
      "data": {
        "genericNodeData": {
          "hide": false,
          "oneOnOne": false,
          "flatten": 0,
          "forceExecution": false
        },
        "periodic": false,
        "tolerance": 1e-7,
        "parametrization": "chordLength"
      },
      "inputs": {
        "points": {
          "connections": [
            {
              "node": "spiral",
              "output": "result",
              "data": {}
            }
          ]
        }
      },
      "position": [
        460,
        40
      ]
    }
  },
  "modules": {}
}

Drawing a list of points draws every point; drawing a list of shapes draws every shape.

Once per item​

Other times you want a function to run once for each item: a sphere at every point, a fillet on every part. Each editor says that in its own way:

  • TypeScript uses the language: points.map(...) or a for loop, with await Promise.all(...) when the function is a kernel call.
  • Blockly has loops: the repeat and for-each blocks of its loops category run the blocks inside them for every item.
  • Rete repeats a component on its own: when several wires feed one input, the component runs once per value, every value against every value or paired 1:1. Lists and node options shows how, and the badges that say what a component received.

Reshaping lists​

The bitbybit.lists functions read and reshape lists in every editor: take an item or a range, reverse, flatten nested lists, group, pair. Lists introduces them.