Separate syntax from invalid regions
05Malformed fragment syntax invalidates the whole fragment; a well-formed but nonexistent or inverse region is ignored individually.
Separate malformed example: ROW=2 MUST be ignored, not silently repaired to row=2. No particular error dialog is required.
Source for this drawing: RFC 7111 · Read RFC section 4.1 ↗
New to this? Start hereA quick picture + helpful background
A message needs an address.
Think of a packet as a small addressed envelope. Devices pass it onward; transport protocols decide what delivery promises an application gets.
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These pictures are analogies to help you learn. The linked RFC explains the actual rules.
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Specified text MUST use the exact lowercase spelling: row=, col=, cell= (§3). Semicolons separate selections of the same kind.
- Specified text MUST use the exact lowercase spelling: row=, col=, cell= (§3). Semicolons separate selections of the same kind.
- On a syntax error, clients MUST ignore the fragment and MUST NOT correct or guess it; reporting the error is a MAY.
- Well-formed specifications are evaluated independently (§4.2). Ignoring one inverse or nonexistent region does not discard valid regions.
Also RFC 7111 §§2.4, 3, 4.2. Overlap presentation is left to the client. The example table is fictional; highlighted regions are client-side selections, not server filtering.
Read the RFC section ↗