[plt-dev] slightly misleading error

From: Carl Eastlund (carl.eastlund at gmail.com)
Date: Fri May 22 15:38:29 EDT 2009

On Fri, May 22, 2009 at 3:35 PM, Anthony Cowley <acowley at seas.upenn.edu> wrote:
>>> How about, "Expression produced 2 values, but the context exected 1."
>> That doesn't include a printout of the 2 values in question, nor a
>> particularly natural place to include them -- at the end of the
>> sentence would be misleading (they're not the 1 value the context
>> expected), and in the middle would break up the explanation if the
>> values took multiple lines to print.
> Right, I left that out for the case when the expression source isn't
> available. If it is available, then it can be something like,
> "Expression (values 'a 'b) produced 2 values, but the context expected 1"
> But since the original complaint was the apparent disagreement between
> a visible highlighted expression and the apparent subject of the error
> sentence, I'm not even sure that printing the expression is so
> critical. If this were a command line compilation, then I expect an
> error message would be along the lines of,
> "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.

Carl Eastlund

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