Sketch 2.0: KCL sketch block execution using ezpz solve

[jtran]

This implements basic sketch block execution and fixed constraints, calling the ezpz solver for the first time.

@settings(experimentalFeatures = allow)

myParam = 4

s = sketch() {
  x = var 0
  y = var 10
  x == 1 + 2
  y == max([5 * myParam, 0])
}

assert(s.x, isEqualTo = 3)
assert(s.y, isEqualTo = 20)

Implementation

1. Execute the block, like any other KCL code block. Disallow sketch blocks within sketch blocks.
   1. When you execute a sketch var, generate a fresh ID with its initial value and push that into a Vec.
   2. When you execute a constraint, like e1 == e2, build a Constraint and push that into a Vec.
2. We now have a list of all sketch vars with their initial values and a list of all constraints.
3. Translate the above to solver inputs, normalizing units, and run the solver. We use the units of module's default length unit.
4. Collect variables defined in the block. Since we push a new stack env to execute the sketch block, similar to how we do when we call a function and need to execute the function's body, we can find all the variables defined in the block.
5. Traverse each variable's value, recursively substituting the solved value for any sketch var.
6. Use the collected variables as the keys and values of a KCL Object/Record for the return value of the sketch block.

I considered converting units "back" based on the units of the initial values of vars. I don't think it makes sense because in general, sketch vars can be passed around like any other values and it may not be intuitive where a sketch var originated. In the future, I could imagine having a parameter or sketch block annotation that configures which units to solve in. But it seems rare to care about it.

Future Work

1. Disallow engine calls in sketch blocks
2. Make solver warnings prettier
3. Change solver config? Using Default now.
4. Send the sketch to the engine
5. Implement more constraints
6. Allow forward references?
7. Expose all this to the frontend

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Project	Deployment	Preview	Comments	Updated (UTC)
modeling-app	Ready	Preview	Comment	Oct 8, 2025 6:41pm

[codspeed-hq]

CodSpeed Performance Report

Merging #8499 will not alter performance

_{Comparing jtran/sketch-block-exec (a98ae26) with main (b1b2d9b)¹}

Summary

✅ 139 untouched
⏩ 92 skipped²

Footnotes

1. No successful run was found on main (ecc410b) during the generation of this report, so b1b2d9b was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 92 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩