E Style

In trying to write an E program (to actually do something useful 
to me), I noted the apparent lack of the C construct:

   (bool ? true_value : false_value)

What I have working now is:

   def location := ( if (filename =~ `@{x}Cave@{y}`)   { 0 } 
else if \
                        (filename =~ `@{x}Frosty@{y}`) { 1 } 
else if \
                        (filename =~ `@{x}TTT@{y}`)    { 2 } 
else    \
                        { -1 })
   if (location == -1) {throw(`ERROR: Filename "$filename" 
yields $location for offset`)}

(The backslashes seem to be needed.)

Is there a cleaner way to code this fragment?

Cheers - Bill

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Bill Frantz        | I like the farmers' market   | Periwinkle
(408)356-8506      | because I can get fruits and | 16345 
Englewood Ave
www.pwpconsult.com | vegetables without stickers. | Los Gatos, 
CA 95032