Literal Alternation Length Profile
Profile UTF-16 lengths of a literal regex alternative bank, retaining empty alternatives and null extrema for no alternatives.
Description
Profile UTF-16 lengths of a literal regex alternative bank, retaining empty alternatives and null extrema for no alternatives.
An alternation of literals can contain empty choices and different code-unit lengths. A profile makes those distinctions visible before pattern construction.
When to use this tool
Profile UTF-16 lengths of a literal regex alternative bank, retaining empty alternatives and null extrema for no alternatives.
- Prepare the supplied literals 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 literals. 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.lengths, result.minimum, result.maximum, result.emptyIndexes. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Return every literal's UTF-16 length, the minimum and maximum or null for an empty list, and indexes whose literal is empty.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| literals | literals. | List of strings; at most 128 entries |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.lengths | The lengths list in the ordering and representation described above. |
| result.minimum | The minimum value under the stated formula or text convention. |
| result.maximum | The maximum value under the stated formula or text convention. |
| result.emptyIndexes | The empty indexes list in the ordering and representation described above. |
{
"input": {
"literals": [
"a",
"xyz",
""
]
},
"output": {
"result": {
"lengths": [
1,
3,
0
],
"minimum": 0,
"maximum": 3,
"emptyIndexes": [
2
]
}
}
}Limitations and assumptions
- Lengths are code units rather than bytes, code points or regex match counts. No pattern is executed.
- All declared input fields are required and unexpected top-level fields are rejected. Numbers must be finite; lists are limited to 128 entries and ordinary text fields to 8,192 UTF-16 code units, with tighter limits where stated.
- JSON text inputs must parse within bounded nesting and size limits. Numeric outputs outside the safe finite range are rejected; large exact integer results use decimal strings. Indexes and half-open spans are zero-based unless a rank is explicitly described as one-based.
Alternative or Complementary methods
Compile generated pattern sources with explicitly chosen flags and test them on bounded representative text. Pattern sources, replacement strings and JSON string spellings require different escaping conventions.
References
Similar or alternative tools
- Literal Alternation Formatter
Build a noncapturing literal alternation with regex metacharacters escaped; empty bank produces a never-matching pattern.
- Literal Pattern Prefix Factoring
Factor the common UTF-16 prefix from literal alternatives and produce an escaped noncapturing pattern; no general regex algebra.