"heritage" in Makefile - makefile

Question

I'm looking a way to overload parts of a Makefile A to another one B, hence extending A.
For instance we have the following makefile A:
TEXT="AHAHA"
default: after-default
before-default:
echo "BEFORE DEFAULT"
default: before-default
echo ${TEXT}
after-default: default
echo "AFTER DEFAULT"
I want to reuse it in a new Makefile B like this:
TEXT="HIHIHI"
before-default:
echo "NEW BEFORE DEFAULT"
The new makefile will print:
NEW BEFORE DEFAULT
HIHIHI
AFTER DEFAULT
This example is a bit absurd it is not possible like this way, but I want to know if it is possible to make such Makefile composition close to this idea.

Answer 1

You can do this:
File Makefile:
# Define default TEXT
TEXT := HAHAHA
# Define default target
after:
#echo AFTER
run:
#echo $(TEXT)
before:
#echo BEFORE
# Define dependencies
run: before
after: run
# Include the new makefile
include inheritance.mk
File inheritance.mk:
# Redefine TEXT
TEXT := HIHIHI
# Redefine before target
before:
# echo NEW BEFORE
When you run make you'll have some warning but it'll work as expected:
inheritance.mk:4: warning: overriding commands for target `before'
Makefile:10: warning: ignoring old commands for target `before'
NEW BEFORE
HIHIHI
AFTER

Answer 2

Your example will be trivially fulfilled by adding include A at the start of B. The new before-default target will override the old one.
vnix$ tail *
==> A <==
TEXT="AHAHA"
before-default: default
echo "BEFORE DEFAULT"
default: after-default
echo ${TEXT}
after-default:
echo "AFTER DEFAULT"
==> B <==
include A
TEXT="HIHIHI"
before-default: default
echo "NEW BEFORE DEFAULT"
vnix$ make -sf A
AFTER DEFAULT
AHAHA
BEFORE DEFAULT
vnix$ make -sf B
B:6: warning: overriding commands for target `before-default'
A:4: warning: ignoring old commands for target `before-default'
AFTER DEFAULT
HIHIHI
NEW BEFORE DEFAULT
This isn't a very good design, though; parametrizing things like you already do with TEXT comes with fewer surprises than having code that is being overridden elsewhere.
(See my comment above re: why the output is in the opposite order from what you were hoping.)