Add support for the experimental MiniZinc black-box propagator interface

CMakeLists.txt

@@ -1170,6 +1170,13 @@ if(GECODE_ENABLE_FLATZINC)
       endif()
     endforeach()
   endif()
+  if(CMAKE_DL_LIBS)
+    foreach(kind shared static)
+      if(TARGET gecodeflatzinc_${kind})
+        target_link_libraries(gecodeflatzinc_${kind} PUBLIC ${CMAKE_DL_LIBS})
+      endif()
+    endforeach()
+  endif()
 endif()
 
 # Compatibility aggregate target for downstream projects expecting Gecode::gecode.

Makefile.in

@@ -819,11 +819,11 @@ endif
 # FLATZINC
 #
 
-FLATZINCSRC0 = flatzinc.cpp registry.cpp branch.cpp
+FLATZINCSRC0 = flatzinc.cpp registry.cpp branch.cpp blackbox.cpp
 FLATZINC_GENSRC0 = parser.tab.cpp lexer.yy.cpp
 FLATZINCHDR0 = ast.hh conexpr.hh option.hh parser.hh \
 	plugin.hh registry.hh symboltable.hh varspec.hh \
-	branch.hh branch.hpp lastval.hh complete.hh
+	branch.hh branch.hpp lastval.hh complete.hh blackbox.hh
 
 FLATZINCSRC = $(FLATZINCSRC0:%=gecode/flatzinc/%)
 FLATZINC_GENSRC = $(FLATZINC_GENSRC0:%=gecode/flatzinc/%)

changelog.in

@@ -75,6 +75,19 @@ This release modernizes the Gecode build infrastructure, adds a
 first-class CMake package for downstream consumers, refreshes the
 autoconf build path, and updates CI coverage for current platforms.
 
+[ENTRY]
+Module: flatzinc
+What:   new
+Rank:   minor
+[DESCRIPTION]
+Add support for the experimental MiniZinc black-box propagator interface. A
+FlatZinc model can request propagation using an external function, implemented
+either as a shared library or as a subprocess, through two generic propagators:
+gecode_blackbox (value propagation, scheduled once all inputs are fixed) and
+gecode_blackbox_bounds (bounds propagation, scheduled on bound changes).The
+blackbox_exec and blackbox_dll annotations select the execution mode and pass
+through extra arguments.
+
 [ENTRY]
 Module: minimodel
 What:   bug

cmake/GecodeSources.cmake

@@ -232,6 +232,7 @@ set(GECODE_GIST_SOURCES
 )
 
 set(GECODE_FLATZINC_SOURCES
+  gecode/flatzinc/blackbox.cpp
   gecode/flatzinc/branch.cpp
   gecode/flatzinc/flatzinc.cpp
   gecode/flatzinc/lexer.yy.cpp