Decision Log

Require whitespace to terminate a URL

Context:  What should ZGL do if an URL ends with a , or ;? Here are two choices:

1. Include the , or ; character as part of the URL.
2. Treat the , or ; as a separate token.

As a point of comparison, many text-processing tools (e.g. email clients) do not include a trailing punctuation character in a URL.

However, if (2), how can a user represent a URL that ends in a , or ;? This would require additional grammar rules. Since I prefer ZGL's grammar to be simple, I choose (1).

Decision:  Whitespace is required to terminate a URL. 

For example, this would be incorrect:

/org/PBS homepage https://www.pbs.org;

Above, a parser would consume the ; as part of the URL. However, then it would not find a terminating ; and fail. 

Here is the correct way to write the graph expression:

/org/PBS homepage https://www.pbs.org ;

Consequences:

• Simpler grammar.
• Simpler to implement.
• Slightly less convenient to type.
• Assymetry: there are no other places where whitespace is required before a terminating semicolon (;).

Status:  Accepted on 2021-02-25.