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bmakelib.enum.define

Defines an enum (aka variant or option.)

It can later be used to verify the value of variables by using bmakelib.enum.error-unless-member.

There are two variations to this feature.

  • as a target dependency
  • as a variable (macro)

Both produce the same results. Except some minor cases, choice of the variation is mostly a matter of style.

Example 1

Makefile using target dependency:

define-enums : bmakelib.enum.define( DaysOfWeek/SUN,MON,TUE,WED,THU,FRI,SAT )
define-enums : bmakelib.enum.define( DISTRO/openSUSE,Debian,Fedora )
include define-enums

Or Makefile using variable (macro):

$(call bmakelib.enum.define,DaysOfWeek/SUN,MON,TUE,WED,THU,FRI,SAT)
$(call bmakelib.enum.define,DISTRO/openSUSE,Debian,Fedora)

Either of the above makefiles defines two enums:

  • DaysOfWeek with 7 possible values: SUN, MON, ...
  • DISTRO with 3 possible values: openSUSE, Debian and Fedora

💡 Note the last line in the first snippet: includeing a non-PHONY target causes it to be evaluated before any other targets. We're using this technic to ensure the enums are defined before we access them.

Example 2

Makefile using target dependency:

publish-package : bmakelib.enum.define( PKG-TYPE/deb,rpm,aur )
publish-package :
	...

Or Makefile using variable (macro):

$(call bmakelib.enum.define,PKG-TYPE/deb,rpm,aur)

Either of the above snippets defines an enum PKG-TYPE with 3 possible values deb, rpm and aur.

In case of the the first snippet (using target dependency), the difference with the method used in example 1 is that PKG-TYPE would not be accessible before publish-package is invoked.

bmakelib.enum.error-unless-member

Verifies if a variable's value is a member of a given enum and aborts make in case it's not.

Note that just like bmakelib.enum.define, there are two variations of error-unless-member.

Example 1

Makefile:

$(call bmakelib.enum.define,DEPLOY-ENV/development,staging,production)

deploy : bmakelib.enum.error-unless-member( DEPLOY-ENV,ENV )
deploy :
	@echo 🚀 Deploying to $(ENV)...

Shell:

$ make ENV=local-laptop deploy
*** 'local-laptop' is not a member of enum 'DEPLOY-ENV'.  Stop.

$ make ENV=production deploy
🚀 Deploying to production...

Example 2

Makefile:

define-enum : bmakelib.enum.define( BUILD-TARGET/android,ios,linux )
include define-enum

deploy :
	$(call bmakelib.enum.error-unless-member,BUILD-TARGET,TARGET)
	@echo 🏭 Building for $(TARGET)...

Shell:

$ make TARGET=windows deploy
*** 'windows' is not a member of enum 'BUILD-TARGET'.  Stop.

$ make TARGET=ios deploy
🏭 building for ios...