I'm a beginner of the Scheme language.
Recently I found that the data type symbol can be displayed using quote, like this:
> 'E
E
> (quote E)
E
However, if the code below executed, every kind of quote may fail:
> (define 'E 123)
> 'E
E: undefined;
cannot reference an identifier before its definition
> 'abc
abc: undefined;
cannot reference an identifier before its definition
