Re: Expansion of #$ in byte-compiled files

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Please correct me if I am not right here, but it appears that in
> byte-compiled files (don't always?) expand #$ to the current elisp
> file name.  I wrote a module containing the following code:

>   (message "x: %S" #$)

The issue here is that #$ is a "reader macro", so it is replaced by the
content of load-file-name when this expression is *read*.  When the .el
file is loaded, this expression is read when load-file-name has the
intended value, but when it is compiled, this expression is read during
byte-compilation (i.e. not during any kind of "load"ing) when
load-file-name is nil.  So #$ will be read as if nil appeared there in
the file.  Hence the byte-compiler will generate code which behaves just like

   (message "x: %S" nil)


-- Stefan