Description
Construct finite-number and decimal-integer-string round trips while retaining safe-integer and exact versus lossy numeric projection labels.
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.
Construct finite-number and decimal-integer-string round trips while retaining safe-integer and exact versus lossy numeric projection labels.
When to use this tool
Use this generator to create reproducible json number precision corpus 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 numbers, integerStrings, kinds, count 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 cases. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.
Sample a numeric value or an exact decimal integer string, serialize and parse it, then compare numeric projection and safe-integer status. For integer strings, use BigInt comparison to detect projection precision loss.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| numbers | Numbers | Required. Array of Finite number.; minimum items 1; maximum items 16. |
| integerStrings | Integer Strings | Required. Array of Text; minimum UTF-16 length 1; maximum UTF-16 length 128.; minimum items 1; maximum items 16. |
| kinds | Kinds | Required. Array of Text; one of "number", "integer-string".; minimum items 1; maximum items 2. |
| count | Requested count; the mechanics explain whether one draw expands into several returned records. | Required. Safe integer; minimum 1; maximum 32. |
| 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 |
|---|---|---|
| cases | Cases | Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32. |
| cases[].kind | Kind | Required. Text; maximum UTF-16 length 65536. |
| cases[].value | Value | Required. Finite number. or Text; maximum UTF-16 length 65536. |
| cases[].json | Json | Required. Text; maximum UTF-16 length 65536. |
| cases[].pretty | Pretty | Required. Text; maximum UTF-16 length 65536. |
| cases[].roundTripExact | Round Trip Exact | Required. Boolean. |
| cases[].safeAsInteger | Safe As Integer | Required. Boolean. |
| cases[].numericProjection | Numeric Projection | Required. Finite number. |
| cases[].projectionExact | Projection Exact | Required. Boolean. |
| 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.
{
"input": {
"numbers": [
0.125
],
"integerStrings": [
"9007199254740993"
],
"kinds": [
"integer-string"
],
"count": 1,
"seed": 42
},
"output": {
"cases": [
{
"kind": "integer-string",
"value": "9007199254740993",
"json": "\"9007199254740993\"",
"pretty": "\"9007199254740993\"\n",
"roundTripExact": true,
"safeAsInteger": false,
"numericProjection": 9007199254740992,
"projectionExact": false
}
],
"randomness": {
"seed": 42,
"source": "seed"
}
}
}Limitations and assumptions
- An exact JSON string round trip does not imply exact conversion to a number. Already numeric inputs have no recoverable pre-binary64 spelling; safeAsInteger and projectionExact answer different questions.
- 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
Similar or alternative tools
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