Description
Check CAS registry token shape and the leading-group zero rule; checksum validation is separate.
Identifier validation can involve several distinct questions: whether text has the expected shape, whether a checksum is consistent, and whether an authority actually assigned the identifier. Formatting and field extraction address narrower questions. Each result must be read according to the particular property the tool checks.
Check CAS registry token shape and the leading-group zero rule; checksum validation is separate.
When to use this tool
Use CAS Registry Leadinggroup Zero Guard when you need the particular shape, formatting, field, or checksum property as one explicit stage in an identifier workflow.
How to use the tool and how it works
- Enter token. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read valid, leadingZero. Inspect valid, leadingZero before interpreting the associated values.
Match the implemented two-to-seven digit leading group followed by a two-digit group and check digit. Return leadingZero only when that shaped first group begins with zero, and valid only when shaped without that zero.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| token | Token | Required. Text; maximum UTF-16 length 8192. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| valid | Whether this tool’s particular check passes; does not imply broader identifier or protocol validity. | Required. Boolean. |
| leadingZero | Leading Zero | Required. Boolean. |
{
"input": {
"token": "64-17-5"
},
"output": {
"valid": true,
"leadingZero": false
}
}Limitations and assumptions
- Malformed structure can give both flags false. This is a spelling guard, not checksum or registry verification, and it does not establish chemical identity or safety.
- 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
Use a complete format and checksum validator when required, then consult the issuing registry or verification process for assignment and identity. Preserve meaningful leading zeros as text.
References
Similar or alternative tools
- CAS Check Digit Remainder Term
Calculate a CAS-style body digit weighted sum and its modulo-10 remainder.
- Validation: Cas Three Part Digit Shape
Check only the three-part CAS Registry Number digit/hyphen shape, explicitly not its check digit or substance registry.