Make solve methods return solution/fail (reference) objects

This replaces the current functionality that forces the user to use a
callback to query the solution or find which assumptions contributed
to failure. The usage of (reference) objects generally makes the system
easier to use and the user doesn't have to care as much about moving
objects.

This also changes the IPASIR-UP implementation to exists through
separate objects. This solves the problem with dynamic typing.

crates/pindakaas-build-macros/src/lib.rs

@@ -102,20 +102,20 @@ macro_rules! ipasir_up_definitions {
 			#[allow(clippy::too_many_arguments)]
 			pub unsafe fn ipasir_connect_external_propagator(
 				slv: *mut std::ffi::c_void,
-					propagator_data: *mut std::ffi::c_void,
-					prop_notify_assignments: unsafe extern "C" fn(*mut std::ffi::c_void, *const i32, usize),
-					prop_notify_new_decision_level: unsafe extern "C" fn(*mut std::ffi::c_void),
-					prop_notify_backtrack: unsafe extern "C" fn(*mut std::ffi::c_void, usize, bool),
-					prop_cb_check_found_model: unsafe extern "C" fn(*mut std::ffi::c_void, *const i32, usize) -> bool,
-					prop_cb_has_external_clause: unsafe extern "C" fn(*mut std::ffi::c_void, *mut bool) -> bool,
-					prop_cb_add_external_clause_lit: unsafe extern "C" fn(*mut std::ffi::c_void) -> i32,
-					is_lazy: bool,
-					forgettable_reasons: bool,
-					notify_fixed: bool,
-					prop_cb_decide: unsafe extern "C" fn(*mut std::ffi::c_void) -> i32,
-					prop_cb_propagate: unsafe extern "C" fn(*mut std::ffi::c_void) -> i32,
-					prop_cb_add_reason_clause_lit: unsafe extern "C" fn(*mut std::ffi::c_void, i32) -> i32,
-					prop_notify_fixed_assignment: unsafe extern "C" fn(*mut std::ffi::c_void, i32),
+				propagator_data: *mut std::ffi::c_void,
+				prop_notify_assignments: unsafe extern "C" fn(*mut std::ffi::c_void, *const i32, usize),
+				prop_notify_new_decision_level: unsafe extern "C" fn(*mut std::ffi::c_void),
+				prop_notify_backtrack: unsafe extern "C" fn(*mut std::ffi::c_void, usize, bool),
+				prop_cb_check_found_model: unsafe extern "C" fn(*mut std::ffi::c_void, *const i32, usize) -> bool,
+				prop_cb_has_external_clause: unsafe extern "C" fn(*mut std::ffi::c_void, *mut bool) -> bool,
+				prop_cb_add_external_clause_lit: unsafe extern "C" fn(*mut std::ffi::c_void) -> i32,
+				is_lazy: bool,
+				forgettable_reasons: bool,
+				notify_fixed: bool,
+				prop_cb_decide: unsafe extern "C" fn(*mut std::ffi::c_void) -> i32,
+				prop_cb_propagate: unsafe extern "C" fn(*mut std::ffi::c_void) -> i32,
+				prop_cb_add_reason_clause_lit: unsafe extern "C" fn(*mut std::ffi::c_void, i32) -> i32,
+				prop_notify_fixed_assignment: unsafe extern "C" fn(*mut std::ffi::c_void, i32),
 			){
 				[<$prefix _connect_external_propagator>](slv, propagator_data, prop_notify_assignments, prop_notify_new_decision_level, prop_notify_backtrack, prop_cb_check_found_model, prop_cb_has_external_clause, prop_cb_add_external_clause_lit, is_lazy, forgettable_reasons, notify_fixed, prop_cb_decide, prop_cb_propagate, prop_cb_add_reason_clause_lit, prop_notify_fixed_assignment)
 			}