On Sat 14 May 2016 22:27, Jan Nieuwenhuizen <jann...@gnu.org> writes:
> Andy Wingo writes:
>
> Something I wanted to ask and I guess now why don't we let functions
> like pair?, null?, string-prefix? not return the thing itself?
So many possible answers, none of them great ;) For example, why have #t
as a value at all -- I don't know :)
But more directly: pair? only returns a boolean because the standard
convention is that a function with a ? on the end returns a boolean. A
counter example is `assoc': it returns a pair or #f, and has no trailing
`?'.
As to why have predicates -- well the idea is that a predicate doesn't
do lookup and doesnt' retrieve a value, it just partitions its domain.
You don't need to return the value because you already have the value --
you passed it as the argument. Also consider boolean? -- what should
(boolean? #f) return? Anyway that's how predicates are understood by
most other Scheme programmers.
> diff --git a/gnu/packages/cross-base.scm b/gnu/packages/cross-base.scm
> (define* (cross-gcc target
> #:optional (xbinutils (cross-binutils target)) libc)
> "Return a cross-compiler for TARGET, where TARGET is a GNU triplet. Use
> @@ -223,7 +309,10 @@ GCC that does not target a libc; otherwise, target that
> libc."
> (append
> (origin-patches (package-source %xgcc))
> (cons (search-patch "gcc-cross-environment-variables.patch")
> - (cross-gcc-patches target))))))
> + (cross-gcc-patches target))))
> + (modules '((guix build utils)))
> + (snippet
> + (cross-gcc-snippet target))))
>
> ;; For simplicity, use a single output. Otherwise libgcc_s & co. are not
> ;; found by default, etc.
> @@ -245,6 +334,7 @@ GCC that does not target a libc; otherwise, target that
> libc."
> #:target target
> #:binutils xbinutils))
> ("binutils-cross" ,xbinutils)
> + ("gcc" ,gcc)
>
> ;; Call it differently so that the builder can check whether the
> "libc"
> ;; input is #f.
Why did you add GCC here? Why was it not needed before?
Other than this nit, LGTM.
Andy
