From 61f90f14af8796bbed074538882e76f1e1bf3333 Mon Sep 17 00:00:00 2001
From: Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au>
Date: Fri, 25 May 2012 13:24:37 +1000
Subject: Try to make some more modular Fixpoint algorithms.

---
 impl/Operator.hpp | 56 ++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 45 insertions(+), 11 deletions(-)

(limited to 'impl/Operator.hpp')

diff --git a/impl/Operator.hpp b/impl/Operator.hpp
index c9b4a06..dee7f47 100644
--- a/impl/Operator.hpp
+++ b/impl/Operator.hpp
@@ -9,6 +9,12 @@ float infinity() {
 }
 
 #include <vector>
+#include "IdSet.hpp"
+
+template<typename T>
+struct Variable;
+template<typename T>
+struct VariableSet : public IdSet<const Variable<T> > {};
 
 template<typename T>
 struct VariableAssignment;
@@ -17,16 +23,20 @@ struct Expression;
 
 template<typename T>
 struct Operator {
-  virtual T operator() (const std::vector< Expression<T>* >&, const VariableAssignment<T>&) const = 0;
+  virtual ~Operator() { }
+  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& rho) const {
+    return (*this)(args, rho, (VariableSet<T>*) NULL);
+  }
+  virtual T operator() (const std::vector< Expression<T>* >&, const VariableAssignment<T>&, VariableSet<T>*) const = 0;
 };
 template<typename T>
 struct Maximum : public Operator<T> {
-  virtual T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& assignment) const {
+  virtual T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& assignment, VariableSet<T>* visited) const {
     T value = -infinity<T>();
     for (typename std::vector< Expression<T>* >::const_iterator it = args.begin();
          it != args.end();
          ++it) {
-      T temporary = (**it)(assignment);
+      T temporary = (**it)(assignment, visited);
       value = (temporary < value ? value : temporary);
     }
     return value;
@@ -34,13 +44,13 @@ struct Maximum : public Operator<T> {
 };
 template<typename T>
 struct Minimum : public Operator<T> {
-  virtual T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& assignment) const {
+  virtual T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& assignment, VariableSet<T>* visited) const {
     T value = infinity<T>();
     for (typename std::vector< Expression<T>* >::const_iterator it = args.begin();
          it != args.end();
          ++it) {
-      T temporary = (**it)(assignment);
-      value = (temporary > value ? value : temporary);
+      T temporary = (**it)(assignment, visited);
+      value = (temporary < value ? temporary : value);
     }
     return value;
   }
@@ -50,7 +60,7 @@ template<typename T>
 struct Constant : public Operator<T> {
   Constant(const T& val)
     : _value(val) { }
-  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass) const {
+  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass, VariableSet<T>*) const {
     return _value;
   }
   private:
@@ -59,10 +69,10 @@ struct Constant : public Operator<T> {
 
 template<typename T>
 struct Addition: public Operator<T> {
-  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass) const {
+  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass, VariableSet<T>* visited) const {
     T sum = (*args[0])(ass);
     for (unsigned int i = 1, size = args.size(); i < size; ++i) {
-      sum += (*args[i])(ass);
+      sum += (*args[i])(ass, visited);
     }
     return sum;
   }
@@ -70,15 +80,39 @@ struct Addition: public Operator<T> {
 
 template<typename T>
 struct Subtraction: public Operator<T> {
-  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass) const {
+  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass, VariableSet<T>* visited) const {
     T sum = (*args[0])(ass);
     for (unsigned int i = 1, size = args.size(); i < size; ++i) {
-      sum -= (*args[i])(ass);
+      sum -= (*args[i])(ass, visited);
     }
     return sum;
   }
 };
 
+template<typename T>
+struct Comma: public Operator<T> {
+  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass, VariableSet<T>* visited) const {
+    if ((*args[0])(ass, visited) == -infinity<T>()) {
+      std::cout << "Comma - neg inf" << std::endl;
+      return -infinity<T>();
+    } else {
+      std::cout << "Comma - finite" << std::endl;
+      return (*args[1])(ass, visited);
+    }
+  }
+};
+
+template<typename T>
+struct Guard: public Operator<T> {
+  T operator() (const std::vector< Expression<T>* >& args, const VariableAssignment<T>& ass, VariableSet<T>* visited) const {
+    if ((*args[0])(ass, visited) < (*args[1])(ass, visited)) {
+      return -infinity<T>();
+    } else {
+      return (*args[2])(ass, visited);
+    }
+  }
+};
+
 #include "VariableAssignment.hpp"
 #include "Expression.hpp"
 
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