[plt-dev] slightly misleading error

From: Anthony Cowley (acowley at seas.upenn.edu)
Date: Fri May 22 16:06:02 EDT 2009

>> "Line 8, Column 7: Expression produced 2 values, but the context expected 1."
>> Or, if the expression, when printed, is reasonably short,
>> "Line 8, (values 'a 'b): Expression produced 2 values, but the context
>> expected 1."
>> Anthony
> Error messages do not usually print out code; they print out dynamic
> values.  The values don't change based on source locations, code
> expansion, compilation, or anything like that.

Fair enough, I guess I'm used to that from GHC, or the backtrace from
a Lisp, or GCC telling one the line number and target of a bad arity
function call rather than just showing the given arguments. But even
if PLT error messages only show dynamic values, the dynamic values
don't seem as important as the expression that generated them so I
don't think it's worth having a confusing error message to highlight
them if it's at all possible to obtain some information about the
expression that generated them. If it's not, then, as you suggested,
the current message that shows the given values probably is the best.


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