Le 22 sept. 2012 à 17:02, Jim Meyering a écrit :
> How about something like this?
>
> release-type =
> \
> $(subst :, , \
> $(if $(RELEASE_TYPE), \
> $(or $(findstring :$(RELEASE_TYPE):,:alpha:beta:stable:),
> \
> $(error invalid RELEASE_TYPE: $(RELEASE_TYPE))), \
> $(error RELEASE_TYPE undefined)))
>
> That's not quite right because it fails to reject RELEASE_TYPE=alpha:beta.
> Adding one more "if" just for that case should do the job:
>
> release-type =
> \
> $(subst :, , \
> $(if $(RELEASE_TYPE), \
> $(if $(findstring :,$(RELEASE_TYPE)), \
> $(error invalid RELEASE_TYPE: $(RELEASE_TYPE)), \
> $(or $(findstring :$(RELEASE_TYPE):,:alpha:beta:stable:), \
> $(error invalid RELEASE_TYPE: $(RELEASE_TYPE)))), \
> $(error RELEASE_TYPE undefined)))
Nice! Further improvement: use " " instead of
":" as separator, as it is a more natural separator in Make,
which removes the need to add and strip these ":", and you
get something which is more generic:
_null := # Null character.
_sp := $(_null) # White space.
RELEASE_TYPES = alpha beta stable
# member-check VARIABLE,VALID-VALUES
member-check = \
$(if $($(1)), \
$(if $(findstring $(_sp),$($(1))), \
$(error invalid $(1): '$($(1))', expected $(2)), \
$(or $(findstring $(_sp)$($(1))$(_sp),$(_sp)$(2)(_sp)), \
$(error invalid $(1): '$($(1))', expected $(2)))), \
$(error $(1) undefined))
$(call member-check,RELEASE_TYPE,$(RELEASE_TYPES))
I also realized that is-equal is findstring $(1),$(2) &&
findstring $(2),$(1).
I couldn't find a means to factor elegantly the checks to
have a single $(error invalid $(1)).
