[Bug-kawa] [bug #13865] Symbols don't evaluate to themselves when they look like units

[Chris Dean]

URL:
  <http://savannah.gnu.org/bugs/?func=detailitem&item_id=13865>

                 Summary: Symbols don't evaluate to themselves when they look
like units
                 Project: Kawa
            Submitted by: ctdean
            Submitted on: Wed 07/20/2005 at 18:09
                Category: Scheme language
                Severity: 3 - Normal
              Item Group: Unexpected result
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open

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Details:

Here's a fun Kawa bug.

We all know that units are available in Kawa:

    #|kawa:4|# 7min
    7min
    #|kawa:5|# (+ 8min (* 2 60s))
    10.0min

The expression 7min represents seven minutes and units can be used in
arithmatic operations.

What if you use a unit that Kawa doesn't know about?  We get a nice
error:

    #|kawa:9|# 10volts
    10volts
    gnu.mapping.UnboundLocationException: Unbound symbol volts$unit
            at gnu.expr.ReferenceExp.eval(ReferenceExp.java:115)
            at gnu.expr.Expression.apply(Expression.java:35)
            ...

The bug is when you use a symbol that looks like a unit number but for
a unit that doesn't exist:

     #|kawa:11|# '7min                  ; works
     7min
     #|kawa:12|# '10volts               ; busted
     (* 10 volts$unit)

You get this result that is clearly not a symbol.






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