[plt-dev] renaming programs in the distribution

At Tue, 20 Apr 2010 14:07:02 -0400, Carl Eastlund wrote:
> On Tue, Apr 20, 2010 at 1:54 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> > At Tue, 20 Apr 2010 13:25:39 -0400, Carl Eastlund wrote:
> >> Version 3 is troublesome.  It gives a short name to encourage people
> >> to run "racket <file>" so they don't have to do long stuff... but then
> >> punishes them if they use that to build a script and ever have a file
> >> with a similar name to a command.
> >
> > That doesn't sound quite right. With option 3, `racket' would decide on
> > file versus command syntactically, without consulting the set of
> > available commands or files. So, changes in available files or commands
> > do not change the interpretation of a command line.
> 
> Okay, let's say I write "racket my-favorite-string".  What syntactic
> decision does "racket" use to pin "my-favorite-string" down as a
> potential command versus a potential file name? 

The absence of ".", "/", and "\" means that it's a command name.

> It still seems to me
> that any potential command may still be something a user might want to
> use as a potential file name.

Yes. In that specific case, you'd have to use `racket run
my-favorite-string' or `racket ./my-favorite-string'.

> > I believe that a script implementor would be punished only if the
> > script was called from its own directory without using a path prefix
> > and when "." is in PATH.
> 
> This sounds like an issue when using racket in #! lines.  That's not
> the kind of script I meant.  I mean a #!/bin/bash script that calls
> something like "racket $*" in it to invoke one or more files.  There
> is trouble if the files coincide with command names, or the syntactic
> shape of commands, or whatever racket uses to decide something is not
> a file name.

I see what you mean. Yes, you'd need to write `racket run "$whatever"'
or `racket -u "$whatever"' if you don't know what shape `"$whatever"'
will have and you want it to be treated as a file name.


Is a script implementer who writes

 racket $*

doing anything sensible at the level of preserving filenames,
considering the way that $* expands to multiple arguments without
quoting them? Probably the script implementer needs to write something
like

 racket -u ${1+"$@"}

Just because bash scripting is fragile and complicated is not a good
reason to make it more so. Still, it may not be the case to try to make
nice.