Polysat: refactor constraints (#5372)

* Refactor: remove sign and dep from constraint

* fix some bugs

* improve log messages

* Add missing premises to lemma

* Rename getter in an attempt to fix linux build

src/math/polysat/clause_builder.h

@@ -0,0 +1,49 @@
+/*++
+Copyright (c) 2021 Microsoft Corporation
+
+Module Name:
+
+    polysat clause builder
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-03-19
+    Jakob Rath 2021-04-6
+
+--*/
+#pragma once
+#include "math/polysat/constraint.h"
+#include "math/polysat/types.h"
+
+namespace polysat {
+
+    /// Builds a clause from literals and constraints.
+    /// Takes care to
+    /// - resolve with unit clauses and accumulate their dependencies,
+    /// - skip trivial new constraints such as "4 <= 1".
+    class clause_builder {
+        solver& m_solver;
+        sat::literal_vector m_literals;
+        constraint_ref_vector m_new_constraints;
+        p_dependency_ref m_dep;
+        unsigned m_level = 0;
+
+    public:
+        clause_builder(solver& s);
+
+        bool empty() const { return m_literals.empty() && m_new_constraints.empty() && m_dep == nullptr && m_level == 0; }
+        void reset();
+
+        /// Build the clause. This will reset the clause builder so it can be reused.
+        clause_ref build();
+
+        void add_dependency(p_dependency* d);
+
+        /// Add a literal to the clause.
+        /// Intended to be used for literals representing a constraint that already exists.
+        void push_literal(sat::literal lit);
+        /// Add a constraint to the clause that does not yet exist in the solver so far.
+        void push_new_constraint(constraint_literal c);
+    };
+
+}