Literal Alternation Formatter
Build a noncapturing literal alternation with regex metacharacters escaped; empty bank produces a never-matching pattern.
Description
Build a noncapturing literal alternation with regex metacharacters escaped; empty bank produces a never-matching pattern.
A regex alternation built from literals must escape each alternative's metacharacters. Source order can affect matching choices.
When to use this tool
Build a noncapturing literal alternation with regex metacharacters escaped; empty bank produces a never-matching pattern.
- 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.pattern. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Escape every literal, preserve order and duplicates, and join them in a noncapturing alternation. An empty list returns a never-match pattern; an empty literal remains an empty alternative.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.pattern | The pattern value under the stated formula or text convention. |
{
"input": {
"literals": [
"a.b",
"x|y"
]
},
"output": {
"result": {
"pattern": "(?:a\\.b|x\\|y)"
}
}
}Limitations and assumptions
- No anchors, flags or slash delimiters are supplied. This is literal pattern construction rather than arbitrary regex composition.
- 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 Length Profile
Profile UTF-16 lengths of a literal regex alternative bank, retaining empty alternatives and null extrema for no alternatives.
- ASCII Character Class Formatter
Format a positive ASCII character class using explicit two-digit hexadecimal escapes, avoiding metacharacter ambiguity.