6.4.2 #include from a string or expression (eval)

The template:

#attr $y = "Let's go $voom!"
#include source=$y
#include raw source=$y
#include source="Bam!  Bam!"

The output:

% voom="VOOM" x.py --env
Let's go VOOM!Let's go $voom!Bam!  Bam!

The generated code:

write(self._includeCheetahSource(VFS(SL,"y",1), trans=trans, 
    includeFrom="str", raw=0, includeID="481020889808.74"))
write(self._includeCheetahSource(VFS(SL,"y",1), trans=trans, 
    includeFrom="str", raw=1, includeID="711020889808.75"))
write(self._includeCheetahSource("Bam!  Bam!", trans=trans, 
    includeFrom="str", raw=0, includeID="1001020889808.75"))

Later in the generated class:

y = "Let's go $voom!"