Selection Through Edit Transform
Transform each selection endpoint with its stated affinity; preserve any resulting reversed orientation rather than silently swap endpoints.
Description
Transform each selection endpoint with its stated affinity; preserve any resulting reversed orientation rather than silently swap endpoints.
Edits move selection boundaries as text lengths change. Independent boundary affinity specifies whether an insertion belongs before or after each selection endpoint.
When to use this tool
Transform each selection endpoint with its stated affinity; preserve any resulting reversed orientation rather than silently swap endpoints.
- Prepare the supplied sourceLength, start, end, editsJson, startRightAffinity, endRightAffinity fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter sourceLength, start, end, editsJson, startRightAffinity, endRightAffinity. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.start, result.end, result.orientationReversed. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Validate a source-length span and an edit list in original coordinates, sorted by start and end before validation. Transform start and end separately with throughEdits using their respective right-affinity flags; return both offsets and orientationReversed when start exceeds end.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| sourceLength | source length. | Integer from 0 to 8192 inclusive |
| start | start. | Finite number |
| end | end. | Finite number |
| editsJson | JSON text, entered as one text field. The decoded structure is illustrated below; it is not a separate file. | Text |
| startRightAffinity | Explicit choice for start right affinity; supply a boolean rather than a text label. | true or false |
| endRightAffinity | Explicit choice for end right affinity; supply a boolean rather than a text label. | true or false |
For the JSON text fields, the following decoded structures show the example records before they are serialized into input strings. Keep field names, list nesting and value types as shown.
[
{
"field": "editsJson",
"decoded": [
{
"start": 1,
"end": 2,
"text": "XY"
}
]
}
]| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.start | The start value under the stated formula or text convention. |
| result.end | The end value under the stated formula or text convention. |
| result.orientationReversed | Whether the operation’s stated orientation test passes; inspect the transformed endpoints without assuming they were reordered. |
{
"input": {
"sourceLength": 3,
"start": 1,
"end": 2,
"editsJson": "[{\"start\":1,\"end\":2,\"text\":\"XY\"}]",
"startRightAffinity": false,
"endRightAffinity": true
},
"output": {
"result": {
"start": 1,
"end": 3,
"orientationReversed": false
}
}
}Limitations and assumptions
- The result is not automatically reordered. Opposing affinities can reverse an empty selection around an insertion; coordinates are UTF-16 units and no text or grapheme-boundary validation is performed.
- Text offsets and lengths use UTF-16 code units unless explicitly described as bytes or code points. CRLF, CR and LF are recognized as line endings; a terminal newline creates a final empty line in the shared line model.
- Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
- Ordinary string lists have at most 128 entries of at most 128 code units each; numeric lists and matrices have separate bounded size checks. Nonfinite results and excessively large serialized outputs are rejected.
- Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.
Alternative or Complementary methods
Use a parser or language-aware editor when quoting, syntax or nested constructs matter. For plain text transforms, keep UTF-16 offsets, Unicode code points, grapheme clusters and UTF-8 byte offsets distinct; apply changes to the same source version used to calculate spans.
References
Similar or alternative tools
- Offset Through Edit Transform
Transform an original offset through nonoverlapping edits; offsets at or inside replaced spans map to start or end by explicit affinity.
- Selection Indent Transform
Transform full lines intersecting a half-open UTF-16 selection, preserving line endings.