Output path comparison

Parsing nix-env's performance statistics failed.

Parse error:
Error("expected ident", line: 1, column: 3)

Evaluation output:
trace: wxGTK30: You cannot enable withWebKit when using withGtk2.
trace: wxGTK30: You cannot enable withWebKit when using withGtk2.
trace: wxGTK30: You cannot enable withWebKit when using withGtk2.
{
  "cpuTime": 192.034,
  "envs": {
    "number": 114925784,
    "elements": 178055327,
    "bytes": 3263255160
  },
  "list": {
    "elements": 210461014,
    "bytes": 1683688112,
    "concats": 8648764
  },
  "values": {
    "number": 244809361,
    "bytes": 5875424664
  },
  "symbols": {
    "number": 337464,
    "bytes": 15502855
  },
  "sets": {
    "number": 30749783,
    "bytes": 8691701320,
    "elements": 351904294
  },
  "sizes": {
    "Env": 16,
    "Value": 24,
    "Bindings": 8,
    "Attr": 24
  },
  "nrOpUpdates": 14933934,
  "nrOpUpdateValuesCopied": 259958209,
  "nrThunks": 173193248,
  "nrAvoided": 162122575,
  "nrLookups": 87649294,
  "nrPrimOpCalls": 69310543,
  "nrFunctionCalls": 100710038,
  "gc": {
    "heapSize": 13472555008,
    "totalBytes": 25414280736
  }
}