#18 and/or defined unconditionally

[John F. Trudeau]

The sense of the "filter" in the definitions of __gmsl_have_or and __gmsl_have_and is inverted, such that the condition is always false.

This causes the and/or macros to be defined unconditionally.

This is confusing for 2 reasons:

1. Though one can see the definitions they can never be called.
2. The return semantics of the GNU-make built-in functions are incompatible with the GMSL functions. The GMSL functions return $(true) on success. The GNU-make functions return an input argument. That makes the GMSL documentation misleading.

redefine-builtin.make - GNUmakefile to demonstrate the issues.
redefine-buildin.out - Output from run of redefine-builtin.make.
__gmsl.patch - Patch to fix flag heuristics

[John Graham-Cumming]

Hmm.

So I made a simple Makefile that contains the following:

$(warning $(origin or))
$(warning $(origin and))
$(warning $(or A,A))
$(warning $(and A,A))
$(warning $(or A,))
$(warning $(and A,))

all:

The output with GNU Make 3.81 (which has native and and or) is...

Makefile:1: undefined
Makefile:2: undefined
Makefile:3: A
Makefile:4: A
Makefile:5: A
Makefile:6:
make: Nothing to be done for `all'.

And with GNU Make 3.80 (which does not)...

Makefile:1: undefined
Makefile:2: undefined
Makefile:3:
Makefile:4:
Makefile:5:
Makefile:6:
make: Nothing to be done for `all'.

So, in both cases the $(origin) is returning undefined making my definitions useless. So I think a totally different approach is needed. How about detecting like this?

true  := T
false :=
native_or = $(or $(true),$(false))
native_and = $(and $(true), $(true))

$(warning $(call native_or) $(call native_and))

Thoughts?

[John Graham-Cumming]

Or perhaps take a 'truth table' approach and do this:

true  := T
false :=

__or_tt := /$(or $(true),$(true))/$(or $(true),$(false))/$(or $(false),$(true))/$(or $(false),$(false))/
__and_tt := /$(and $(true),$(true))/$(and $(true),$(false))/$(and $(false),$(true))/$(and $(false),$(false))/

native_or := $(if $(filter /T/T/T//,$(__or_tt)),$(true),$(false))
native_and := $(if $(filter /T////,$(__and_tt)),$(true),$(false))

[John Graham-Cumming]

Done