[metapost] mpost -no-parse-first-line

[Nicola]

Hi,
I hoped to be able to make an executable MetaPost source file by writing:

#!/usr/bin/env mpost -no-parse-first-line
\relax % Needed?
%MetaPost code goes here
end.

but it doesn't work:

This is MetaPost, Version 1.005 (Web2C 7.5.7)
(./foo.mp
>> #!
>> usr
! Not implemented: (unknown numeric)/(unknown numeric).
<to be read again> 
                   /
l.1 #!/usr/
           bin/env mpost -no-parse-first-line
? 

Has -no-parse-first-line indeed any effect?

Nicola