Description
Generate sampled push, pop and peek operations with bottom-to-top LIFO snapshots, explicit empty-stack underflows and a delegated top-first final view.
An operation trace pairs an ordered request stream with the state after each step. Empty operations, ties, evictions, and boundary indexes are part of the modeled contract rather than incidental display details.
Generate sampled push, pop and peek operations with bottom-to-top LIFO snapshots, explicit empty-stack underflows and a delegated top-first final view.
When to use this tool
Use this generator to create reproducible stack operation trace 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 initialValues, values, operations, eventCount 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 events, finalStack, finalTopFirst. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.
Sample push, pop, or peek operations. Push draws a supplied value; pop removes the last value and peek reads it. Return a bottom-to-top snapshot after each operation, explicit underflow flags and null values for empty reads, plus a delegated top-first final view.1
Delegated operations used for this result: reverse. Their calculation or parsing conventions apply to the corresponding result fields.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| initialValues | Initial Values | Required. Array of Text; maximum UTF-16 length 64.; minimum items 0; maximum items 16. |
| values | Values | Required. Array of Text; maximum UTF-16 length 64.; minimum items 1; maximum items 16. |
| operations | Operations | Required. Array of Text; one of "push", "pop", "peek".; minimum items 1; maximum items 3. |
| eventCount | Event Count | Required. Safe integer; minimum 1; maximum 64. |
| 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 |
|---|---|---|
| events | Events | Required. Array of Object; no unknown keys.; minimum items 0; maximum items 64. |
| events[].kind | Kind | Required. Text; one of "push", "pop", "peek". |
| events[].value | Value | Required. Text; maximum UTF-16 length 64. or Null. |
| events[].underflow | Underflow | Required. Boolean. |
| events[].stack | Stack | Required. Array of Text; maximum UTF-16 length 64.; minimum items 0; maximum items 80. |
| finalStack | Final Stack | Required. Array of Text; maximum UTF-16 length 64.; minimum items 0; maximum items 80. |
| finalTopFirst | Final Top First | Required. Array of Text; maximum UTF-16 length 64.; minimum items 0; maximum items 80. |
| 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": {
"initialValues": [
"a"
],
"values": [
"b",
"c"
],
"operations": [
"pop",
"push",
"peek"
],
"eventCount": 4,
"seed": 42
},
"output": {
"events": [
{
"kind": "push",
"value": "b",
"underflow": false,
"stack": [
"a",
"b"
]
},
{
"kind": "peek",
"value": "b",
"underflow": false,
"stack": [
"a",
"b"
]
},
{
"kind": "peek",
"value": "b",
"underflow": false,
"stack": [
"a",
"b"
]
},
{
"kind": "pop",
"value": "b",
"underflow": false,
"stack": [
"a"
]
}
],
"finalStack": [
"a"
],
"finalTopFirst": [
"a"
],
"randomness": {
"seed": 42,
"source": "seed"
}
}
}Limitations and assumptions
- Underflow is an intentional trace event rather than an invalid outer input. Snapshot work is bounded. Duplicate values are allowed and this does not execute a concurrent stack implementation.
- 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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