Random Edit Script Reconstruction Challenge Generator

Description

Generate and replay bounded Unicode code-point edit attempts with explicit empty-text no-op controls, retaining the target and a separately delegated minimum edit distance; the planted script need not be minimum.

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 edit script reconstruction challenge 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 source, alphabet, operations, editCount 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 source, target, edits, minimumDistance. Use the conventions below. Keep answer-bearing fields separate when presenting an exercise.

Represent the source as Unicode code points and apply sampled insert, delete, or replace edits at current code-point indexes. Record before/after values and applied flags, return the final target, and delegate the minimum Levenshtein distance.^[1]

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

Input field	Meaning and units	Accepted input
source	Source	Required. Text; maximum UTF-16 length 64.
alphabet	Alphabet	Required. Array of Text; minimum UTF-16 length 1; maximum UTF-16 length 2.; minimum items 1; maximum items 8.
operations	Operations	Required. Array of Text; one of "insert", "delete", "substitute".; minimum items 1; maximum items 3.
editCount	Edit Count	Required. Safe integer; minimum 1; maximum 8.
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
source	Source	Required. Text; maximum UTF-16 length 64.
target	Target	Required. Text; maximum UTF-16 length 80.
edits	Edits	Required. Array of Object; no unknown keys.; minimum items 0; maximum items 8.
edits[].kind	Kind	Required. Text; one of "insert", "delete", "substitute".
edits[].index	Index	Required. Safe integer; minimum 0; maximum 40.
edits[].before	Before	Required. Text; maximum UTF-16 length 2.
edits[].after	After	Required. Text; maximum UTF-16 length 2.
edits[].applied	Applied	Required. Boolean.
minimumDistance	Minimum Distance	Required. Safe integer; minimum 0; maximum 40.
randomness	Replay source and normalized 32-bit seed, or null seed for an advancing context source.	Required. Object; no unknown keys.
randomness.seed	Optional safe-integer 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": {
    "source": "cat",
    "alphabet": [
      "o",
      "s"
    ],
    "operations": [
      "insert",
      "delete",
      "substitute"
    ],
    "editCount": 2,
    "seed": 42
  },
  "output": {
    "source": "cat",
    "target": "co",
    "edits": [
      {
        "kind": "delete",
        "index": 1,
        "before": "a",
        "after": "",
        "applied": true
      },
      {
        "kind": "substitute",
        "index": 1,
        "before": "t",
        "after": "o",
        "applied": true
      }
    ],
    "minimumDistance": 2,
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

A noninsert edit on empty text is recorded unapplied; replacement can leave a character unchanged. The generated script is not necessarily a shortest script, and edit count need not equal minimumDistance.
A replay requires the same complete input and implementation. The stated sampling convention applies within its eligible space. A finite draw does not exhaust all possible outputs; repeats remain possible unless a distinct-selection rule is explicit.
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 Edit Script Reconstruction Challenge Generator — tool.io
Calculation or validation: distance/levenshtein — tool.io

Similar or alternative tools

Sequential Pattern Mining Tool
Mine bounded frequent ordered subsequences of single-event string sequences using prefix projection, allowing arbitrary gaps and repeated events and counting each source sequence at most once per pattern.
Random Configuration Override Chain Fixture Generator
Permute supplied flat configuration layers and retain first- or last-wins results, explicit null deletion and per-key winning-layer provenance.