The Lab

Write a Vex chain, or start from a preset. The Lab reads the chain as you type, evaluates it at each record of the space, and draws the result at each record. Select a record to see the trace of the evaluation there.

BoxesLifeTreeRowsReset boxesCopy link

Four boxes on graph paper: a record space. Drag a box to change the results.

root.from("position")
  .others((e) => e._.distance("position"))
  .min()

root.from("position") .others((e) => e._.distance("position")) .min()

The Lab reads the chain as you type. It knows root, const lines and arrow functions.

ops of Num at A:addsubtractmultiplydividemodpowminmaxclampabsnegatesqrtfloorceilroundgtgtelt

The result at each of the 4 records

A	5
B	5
C	7.28
D	6.32

The trace at A

1. ref position @A → (2, 2)
2. var $0 @B → (2, 2)
3. ref position @B → (6, 5)
4. app distance @B → 5
5. var $0 @C → (2, 2)
6. ref position @C → (13, 3)
7. app distance @C → 11.05
8. var $0 @D → (2, 2)
9. ref position @D → (4, 11)
10. app distance @D → 9.22
11. each others @A → [B: 5, C: 11.05, D: 9.22]
12. let $0 @A → [B: 5, C: 11.05, D: 9.22]
13. app min @A → 5

The program as JSON

{
  "tag": "app",
  "op": "min",
  "args": [
    {
      "tag": "let",
      "bind": {
        "$0": {
          "tag": "ref",
          "path": [
            "position"
          ]
        }
      },
      "body": {
        "tag": "each",
        "axis": {
          "t": "others"
        },
        "body": {
          "tag": "app",
          "op": "distance",
          "args": [
            {
              "tag": "var",
              "name": "$0"
            },
            {
              "tag": "ref",
              "path": [
                "position"
              ]
            }
          ]
        }
      }
    }
  ]
}

How the Lab works

• Four spaces. The boxes are a record space. Life is a grid space. The organization chart is a tree space. The rows are an array space. Each space has its own moves and axes.
• A safe reader. The Lab does not run your text as JavaScript. A small reader reads the chain: const lines, calls, arrow functions and literals. It permits only the members of the builder, so a shared link cannot run other code.
• The ops of the current value. Under the editor, the chips show the ops of the domain of the result at the origin. A chip adds the op to the end of the chain. After an axis, the chips show the reductions of the list.
• A link for each program. “Copy link” puts the space and the code in the address of the page. The link opens the same program.
• Programs are data. The last panel shows the program as JSON: the same tree that serialize gives.

The boxes are the same four boxes as the other pages. Drag a box in the Lab, and the results change.