REBOL 3 Errors: no-value

Summary

This is a very common error. It means that your code tried to evaluate a word that was not defined. Simply, it had no value associated with it, as explained in expressions: values.

If you are sure that the word was defined, then the problem could be that the word was defined in a different context than where it was used.

Examples

For example, if foo is not defined in the global context:

>> foo
** Script Error: foo has no value

Here foo is defined in an object!, but still not in the global context:

>> test: object [foo: 10]
>> foo
** Script Error: foo has no value

Similarly for foo when defined in a function!, but an attempt is made to use it outside that function:

>> test: func [arg /local foo] [arg + foo]
>> foo
** Script Error: foo has no value

Related

You can use value? to check if a word has been defined in context.