I converted github-copilot-cli in nixpkgs and here are the eval performance results:

• before.json

{
  "cpuTime": 0.7983409762382507,
  "envs": {
    "bytes": 16531624,
    "elements": 828921,
    "number": 618766
  },
  "gc": {
    "heapSize": 402915328,
    "totalBytes": 180765008
  },
  "list": {
    "bytes": 3000672,
    "concats": 21613,
    "elements": 375084
  },
  "nrAvoided": 864119,
  "nrFunctionCalls": 558479,
  "nrLookups": 201175,
  "nrOpUpdateValuesCopied": 4886502,
  "nrOpUpdates": 45948,
  "nrPrimOpCalls": 391174,
  "nrThunks": 1152515,
  "sets": {
    "bytes": 98766016,
    "elements": 5996044,
    "number": 176832
  },
  "sizes": {
    "Attr": 16,
    "Bindings": 16,
    "Env": 16,
    "Value": 24
  },
  "symbols": {
    "bytes": 386981,
    "number": 37425
  },
  "values": {
    "bytes": 36922296,
    "number": 1538429
  }
}

• after.json

{
  "cpuTime": 0.510466992855072,
  "envs": {
    "bytes": 9614136,
    "elements": 488211,
    "number": 356778
  },
  "gc": {
    "heapSize": 402915328,
    "totalBytes": 91434160
  },
  "list": {
    "bytes": 1416640,
    "concats": 14601,
    "elements": 177080
  },
  "nrAvoided": 511866,
  "nrFunctionCalls": 321155,
  "nrLookups": 126367,
  "nrOpUpdateValuesCopied": 2282699,
  "nrOpUpdates": 28766,
  "nrPrimOpCalls": 240324,
  "nrThunks": 639741,
  "sets": {
    "bytes": 45028896,
    "elements": 2733143,
    "number": 81163
  },
  "sizes": {
    "Attr": 16,
    "Bindings": 16,
    "Env": 16,
    "Value": 24
  },
  "symbols": {
    "bytes": 370066,
    "number": 34762
  },
  "values": {
    "bytes": 20532984,
    "number": 855541
  }
}

In reply to @adis:blad.is
A concern that often comes up when when talking about lock file parsing in nixpkgs performance.
I wanted to have ballpark numbers to refer to.

In reply to @raitobezarius:matrix.org
You know that I nerdsnipped @tomberek on adding the parsing built-in based on a EBNF grammar (a packrat parser)