Sequence diff hunks

sequence-diff-hunks · version 1.0.0 · Sequences & diffs · free, no key needed

Group a Myers sequence edit script into context hunks with 0-based original addresses.

Use when you need to: sequence diff hunks · grouped sequence diff hunks · sequence context hunks.

Supported

• sequence diff hunks
• grouped sequence diff hunks
• sequence context hunks

Not supported

• fuzzy matching
• patience diff
• histogram diff
• offset search
• RFC 6902 JSON Patch
• csv row diff

Behavior

• left and right are sequences of JSON null, boolean, string, or IEEE-754 safe integer items.
• Hunks are built from the Myers SES via hunksFromSes. context defaults to 3, may be 0, and is at most 16.
• Changes separated by fewer than 2*context keep ops merge into one hunk.
• old_start and new_start are 0-based. When old_count is 0, old_start is the insertion index in [0, left.length].
• Hunk ops are {op, value} only. identical is true iff there are no change ops.
• For left ["A","B","C"] and right ["A","X","C"] with context 0 there is one hunk at old_start 1 replacing B with X.
• The string "__proto__" is an ordinary item. Unknown input fields are rejected.

Input

• left (array of null or boolean or string or integer, required): max items 1024
• right (array of null or boolean or string or integer, required): max items 1024
• context (integer, optional): min 0; max 16

Output

• hunks (array of any, required): max items 1024
• identical (boolean, required)

Limits

• max sequence items: 1024
• max item string bytes: 4096
• max text bytes: 262144
• max context: 16
• max hunks: 1024
• max output bytes: 1048576

Example

Request input:

{
  "left": [
    "A",
    "B",
    "C"
  ],
  "right": [
    "A",
    "X",
    "C"
  ],
  "context": 0
}

Response:

{
  "result": {
    "hunks": [
      {
        "old_start": 1,
        "old_count": 1,
        "new_start": 1,
        "new_count": 1,
        "ops": [
          {
            "op": "delete",
            "value": "B"
          },
          {
            "op": "insert",
            "value": "X"
          }
        ]
      }
    ],
    "identical": false
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "sequence-diff-hunks",
  "version": "1.0.0",
  "input": {
    "left": [
      "A",
      "B",
      "C"
    ],
    "right": [
      "A",
      "X",
      "C"
    ],
    "context": 0
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/sequence-diff-hunks/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"left":["A","B","C"],"right":["A","X","C"],"context":0}'

The machine-readable contract is at /v1/tools/sequence-diff-hunks/versions/1.0.0.

CLI

node cli.mjs run sequence-diff-hunks 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Sequence apply hunks: Apply disjoint original-address sequence hunks with exact context and no fuzz.
• Sequence invert hunks: Invert sequence hunks by swapping delete/insert and old/new counts.
• Sequence apply edit script: Apply a keep/delete/insert edit script to a bounded sequence with exact value matching and no fuzz.
• Sequence compose edit scripts: Compose two sequence edit scripts into one per-item keep/delete/insert script.
• Sequence edit script: Compute the Myers shortest edit script between two bounded sequences, with keep/delete/insert counts.
• Sequence index map: Map each left-sequence index to a kept right index, or null if deleted, and list inserted right indices.