If the DTD is a tool, then yes, the issue is better tools. The way to do it in a DTD is: 
<!ATLIST box color (red|blue|green) blue>

[download]
This allows 
<box color=red />

[download]
but not 
<box color=large />

[download]
The default is blue in this example.

In reply to Re^3: Config Files Redux by traveler
in thread Config Files Redux by traveler

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