Description
Distinguish positional interpretations of Unicode FEFF without claiming a decoded scalar proves a byte-level BOM; internal FEFF is a legacy ZWNBSP use.
Text positions can be measured in UTF-16 code units, Unicode code points, grapheme clusters, or modeled display columns. These coordinates are not interchangeable. Invisible markers and delimiter policies can also affect interpretation even when a string looks unchanged, so the chosen representation needs to stay explicit.
Distinguish positional interpretations of Unicode FEFF without claiming a decoded scalar proves a byte-level BOM; internal FEFF is a legacy ZWNBSP use.
When to use this tool
Use Text: Unicode Bom Vs Zw Nobreak Label when you need the stated marker, coordinate, delimiter, or normalization operation under an explicit text representation.
How to use the tool and how it works
- Enter codepoint, atStreamStart. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read result. Expand result to inspect the returned fields.
For a valid scalar return isFEFF and label U+FEFF as possible-byte-order-mark only when atStreamStart, otherwise zero-width-no-break-space-legacy. Other scalars receive other-codepoint inside result.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| codepoint | Codepoint | Required. Safe integer. |
| atStreamStart | Caller-supplied position flag; does not inspect an encoded stream. | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| result | Result | Required. Object. |
{
"input": {
"codepoint": 65279,
"atStreamStart": true
},
"output": {
"result": {
"isFEFF": true,
"interpretation": "possible-byte-order-mark"
}
}
}Limitations and assumptions
- Stream position is supplied and the input is already a decoded numeric scalar. The tool does not inspect bytes, determine an encoding, or prove that U+FEFF was an actual byte-order mark.
- Outputs are nested inside result. The field tables state structural bounds; the mechanics also specify cross-field constraints. Malformed inputs and unsupported domains cause errors. A successful false flag, empty branch value, or zero placeholder has the meaning stated above and is distinct from an input error.
Alternative or Complementary methods
Choose the coordinate system required by the consumer. Use a full parser, renderer, or segmentation method when a local marker or delimiter rule cannot determine the complete text behavior.
References
Similar or alternative tools
- Text: Whitespace Nobreak Vs Breakable Label
Classify only ordinary space U+0020 and no-break spaces U+00A0/U+202F into their Unicode line-break classes; not a full Unicode line-breaking engine.
- Text: Bidi Control Visible Name Label
Name one of the twelve Unicode Bidi_Control code points for visible inspection, without applying the bidirectional layout algorithm.