Description
Check text for one digit, hash, or asterisk followed by optional U+FE0F and U+20E3.
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.
Check text for one digit, hash, or asterisk followed by optional U+FE0F and U+20E3.
When to use this tool
Use Unicode Keycap Sequence Base Token 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 text. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read valid, base, variationSelector. Inspect valid, variationSelector before interpreting the associated values.
Check text for one digit, hash, or asterisk followed by optional U+FE0F and U+20E3. Return valid, its base when valid, and whether that accepted sequence includes the selector.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| text | Text | Required. Text; maximum UTF-16 length 8192. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| valid | Whether this tool’s specific rule passes, not a broader approval. | Required. Boolean. |
| base | Base | Required. Text; maximum UTF-16 length 8192. |
| variationSelector | Variation Selector | Required. Boolean. |
{
"input": {
"text": "1️⃣"
},
"output": {
"valid": true,
"base": "1",
"variationSelector": true
}
}Limitations and assumptions
- Malformed text returns empty base and false selector status. This is sequence shape only, not full grapheme segmentation, emoji rendering, or font compatibility.
- 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: Bidi Control Visible Name Label
Name one of the twelve Unicode Bidi_Control code points for visible inspection, without applying the bidirectional layout algorithm.
- Text: Combining Mark Leading Position Flag
Check whether the first scalar of a string has Unicode Mark general category using the runtime Unicode property table; not grapheme segmentation or a validity judgment.