Re: invalid code for Special literals

[Per Bothner <per at bothner dot com>]

Vladimir Tsichevski wrote:
> Hi,
>
> if you use literals of gnu.expr.Special type (literals beginning with 
> #!), kawa generates constant init sequence that causes
> java verification error.  For example:
>
> wowa at src$ cat bug.scm
> #!default
> wowa at src$ kawa --main -C bug.scm
> (compiling bug.scm)
> wowa at src$ java bug
> Exception in thread "main" java.lang.VerifyError: (class: bug, method: 
> <clinit> signature: ()V) Bad type in putfield/putstatic
> wowa at src$
>
> The origin of the error is in that the the following code are generated:
>
>    static final Special Lit0 = Special.make("default");
>
> and Special.make() is defined as returning java.lang.Object, but not a 
> gnu.expr.Special, as it supposed to be.
>
> To make Special.make() to return Specials we should either:
>
> 1. Exclude the Special.eof from the list of Special constant, use 
> gnu.lists.Sequence.eofValue instead
> 2. Let eof constant be Special, use Special.eof instead of 
> gnu.lists.Sequence.eofValue (patch included)

I chose option 1 instead. The reason is that I don't to
have gnu.lists depend on gnu.expr.  The disadvantage is that
printing eofValue is ugly, so I changed it to use a new
Eofclass instead.
Perhaps a better solution would be to move Special into
gnu.lists, or some similar utility package, that contains
helper classes but does not depend on gnu.expr.
--
	--Per Bothner
per at bothner dot com   http://per.bothner.com/