Re: How can I call "notdir" on a file name that contains spaces?

[John Graham-Cumming]

Eric Hanchrow wrote:
> Here's an example makefile that doesn't do what I want.
>
>     name   := I have a space/x
>
>     worse:
>             @echo input  is $(name)
>             @echo output is $(notdir $(name))
>
>     # I see
>
>     # input  is I have a space/x
>     # output is I have a x
>
>
>     # But I wish I'd have seen
>     # input  is I have a space/x
>     # output is x
>
> At first, I thought this behavior was a bug, but then I realized that
> it's working exactly as specified: notdir treats its argument as a
> _whitespace-separated_ list of file names.  That makes it difficult to
> deal with file names that themselves contains spaces.  Is there a way
> to do it?

This is a classic GNU Make problem.  GNU Make assumes that spaces are a 
list separator (as you point out) and hence you get this problem.  The 
only way around this for your purpose is to transform the file name to 
something without spaces and then convert it back.

The simplest way to do this is to convert every space in the file name 
to a ? (since ? won't appear in a real file name we can safely use it) 
and then convert it back afterwards.

Here are two simple functions that will do that:

    sq = $(subst $(sp),?,$1)
    qs = $(subst ?,$(sp),$1)

    e :=
    sp := $(e) $(e)

sq converts a file name so that all spaces are replaced by ?, qs does 
the opposite.

So you could rewrite your example

    name   := I have a space/x

    worse:
        @echo input  is $(name)
        @echo output is $(call qs,$(notdir $(call sq,$(name))))

And you would get the following output:

    input is I have a space/x
    output is x

Now a nice side effect of using ? is that it's the single character 
globbing symbol so a file name transformed using sq can be safely passed 
into GNU Make's $(wildcard) function to determine if a file exists.  Of 
course if you were to have file names like "I have" and "Idhave" then 
this globbing doesn't do quite what you want, but it's pretty close.

John.
--
John Graham-Cumming
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