Random JSON Pointer Navigation Exercise Generator

Description

Generate bounded object/array documents with caller key strings and primitive values, then compose canonical escaped RFC 6901 navigation questions and deliberate missing paths with delegated answers; preserve found-null versus missing distinction, avoid inherited-property missing keys, and do not claim the old resolver enforces every pointer syntax restriction.

A parser corpus pairs literal input spellings or structured documents with observable parser results or explicitly constructed expectations. Successful parsing, semantic validity, and exact round-trip preservation are separate properties, so test records retain the relevant evidence.

When to use this tool

Use this generator to create reproducible json pointer navigation exercise cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.

How to use the tool and how it works

Supply keys, recordCount, valueKinds, minimumValue, maximumValue, textChoices, trueProbability, queryCount, missingProbability in the field shapes below. Set seed when you need an explicit replay.
Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
Read document, queries. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.

Generate records and choose existing root, array, record, or field paths, or deliberately missing indexes/keys. Escape pointer tokens with ~0 and ~1, delegate resolution, and independently verify found and valueJson against own-property traversal.^[1]

Delegated operations used for this result: pointer. Their calculation or parsing conventions apply to the corresponding result fields.^[2]

Input field	Meaning and units	Accepted input
keys	Keys	Required. Array of Text; maximum UTF-16 length 32.; minimum items 1; maximum items 8.
recordCount	Record Count	Required. Safe integer; minimum 1; maximum 16.
valueKinds	Value Kinds	Required. Array of Text; one of "integer", "text", "boolean", "null".; minimum items 1; maximum items 4.
minimumValue	Minimum Value	Required. Safe integer.
maximumValue	Maximum Value	Required. Safe integer.
textChoices	Text Choices	Required. Array of Text; maximum UTF-16 length 64.; minimum items 1; maximum items 16.
trueProbability	True Probability	Required. Finite number; minimum 0; maximum 1.
queryCount	Query Count	Required. Safe integer; minimum 1; maximum 64.
missingProbability	Missing Probability	Required. Finite number; minimum 0; maximum 1.
seed	Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed.	Optional. Safe integer.

Output field	Interpretation	Returned shape
document	Document	Required. Object; no unknown keys.
document.records	Records	Required. Array of Object.; minimum items 1; maximum items 16.
queries	Queries	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 64.
queries[].pointer	Pointer	Required. Text; maximum UTF-16 length 128.
queries[].found	Found	Required. Boolean.
queries[].valueJson	Value Json	Required. Text; maximum UTF-16 length 65536. or Null.
randomness	Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source.	Required. Object; no unknown keys.
randomness.seed	Optional numeric replay seed; normalization and precedence are explained below.	Required. Safe integer. or Null.
randomness.source	Source	Required. Text; one of "context", "seed".

An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.

json

{
  "input": {
    "keys": [
      "a/b",
      "~x"
    ],
    "recordCount": 2,
    "valueKinds": [
      "integer",
      "null"
    ],
    "minimumValue": 0,
    "maximumValue": 4,
    "textChoices": [
      "x"
    ],
    "trueProbability": 0.5,
    "queryCount": 4,
    "missingProbability": 0.25,
    "seed": 42
  },
  "output": {
    "document": {
      "records": [
        {
          "a/b": null,
          "~x": 4
        },
        {
          "a/b": null,
          "~x": 2
        }
      ]
    },
    "queries": [
      {
        "pointer": "/records/0/~0x",
        "found": true,
        "valueJson": "4"
      },
      {
        "pointer": "/records/0/a~1b",
        "found": true,
        "valueJson": "null"
      },
      {
        "pointer": "/records/1/missing-0",
        "found": false,
        "valueJson": null
      },
      {
        "pointer": "/records",
        "found": true,
        "valueJson": "[{\"a/b\":null,\"~x\":4},{\"a/b\":null,\"~x\":2}]"
      }
    ],
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

An empty pointer addresses the document root. A found null value differs from a missing path. The generated cases are bounded and do not access prototype properties or arbitrary remote documents.
A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.

Alternative or Complementary methods

For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.

References

Tool behavior and example: Random JSON Pointer Navigation Exercise Generator — tool.io
Calculation or validation: json/pointer — tool.io

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