From e043ee06a51a8d8c68f8cb0984d4f7bd8915bea8 Mon Sep 17 00:00:00 2001
From: Carlo Zancanaro <carlo@carlo-laptop>
Date: Tue, 29 May 2012 22:42:25 +1000
Subject: First attempt a range parser - likely not correct.

---
 impl/main.cpp | 106 +++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 79 insertions(+), 27 deletions(-)

(limited to 'impl/main.cpp')

diff --git a/impl/main.cpp b/impl/main.cpp
index 530556f..21be64b 100644
--- a/impl/main.cpp
+++ b/impl/main.cpp
@@ -19,53 +19,96 @@ extern "C" {
 using namespace std;
 
 template<typename T>
-Expression<T>* treeToExpression(pANTLR3_BASE_TREE node, EquationSystem<T>& system) {
+std::pair<Expression<T>*, Expression<T>*> treeToExpression(pANTLR3_BASE_TREE node, EquationSystem<T>& system, bool negative=false) {
   ANTLR3_UINT32 num = node->getChildCount(node);
 
   string name = (char*) node->getText(node)->chars;
 
-  // leaf node - constant or variable
+  // leaf node - variable
   if (num == 0) {
-    if (name == "inf") {
-      return system.newExpression(new Constant<T>(infinity<T>()));
-    } else {
-      stringstream stream(name);
-      T output;
-      if (stream >> output) {
-        return system.newExpression(new Constant<T>(output));
-      } else {
-        return system.newExpression(system.newVariable(name));
-      }
+    return std::pair<Expression<T>*, Expression<T>*>(
+        system.newExpression(system.newVariable(name + "_l")),
+        system.newExpression(system.newVariable(name + "_u")));
+  }
+
+  // a range itself
+  if (name == "RANGE") {
+    pANTLR3_BASE_TREE childNode;
+    string childName;
+    T firstValue, secondValue;
+
+    childNode = (pANTLR3_BASE_TREE) node->getChild(node, 0);
+    childName = (char*) childNode->getText(childNode)->chars;
+    stringstream firstStream(childName);
+    if (!(firstStream >> firstValue)) {
+      throw "Invalid number.";
+    }
+    if (negative) firstValue = -firstValue;
+
+    childNode = (pANTLR3_BASE_TREE) node->getChild(node, 1);
+    childName = (char*) childNode->getText(childNode)->chars;
+    stringstream secondStream(childName);
+    if (!(secondStream >> secondValue)) {
+      throw "Invalid number.";
     }
+    if (negative) secondValue = -secondValue;
+
+    return std::pair<Expression<T>*, Expression<T>*>(
+        system.newExpression(new Constant<T>(firstValue)),
+        system.newExpression(new Constant<T>(secondValue)));
   }
 
-  // other operators
-  std::vector<Expression<T>*> args;
+  if (name == "-") {
+    negative = true;
+  }
+
+  // subexpressions
+  std::vector<Expression<T>*> firstArgs;
+  std::vector<Expression<T>*> secondArgs;
   pANTLR3_BASE_TREE childNode;
   for (unsigned int i = 0; i < num; ++i) {
     childNode = (pANTLR3_BASE_TREE) node->getChild(node, i);
-    args.push_back(treeToExpression(childNode, system));
+    std::pair<Expression<T>*, Expression<T>*> expr = treeToExpression(childNode, system, negative);
+    firstArgs.push_back(expr.first);
+    secondArgs.push_back(expr.second);
+  }
+
+  // other operators
+  if (name == "-") {
+    //if (firstArgs.size() == 1) { // secondArgs.size() == firstArgs.size()
+    return std::pair<Expression<T>*, Expression<T>*>(
+        secondArgs[0],
+        firstArgs[0]);
   }
 
   if (name == "max") {
-    return system.newMaxExpression(args);
+    return std::pair<Expression<T>*, Expression<T>*>(
+        system.newMaxExpression(firstArgs),
+        system.newMaxExpression(secondArgs));
   } else {
-    Operator<T>* op = NULL;
+    // we need two because expressions delete their operator
+    // bit of a silly design by me
+    Operator<T>* firstOp = NULL;
+    Operator<T>* secondOp = NULL;
     if (name == "min") {
-      op = new Minimum<T>();
+      firstOp = new Minimum<T>();
+      secondOp = new Minimum<T>();
     } else if (name == "+") {
-      op = new Addition<T>();
-    } else if (name == "-") {
-      op = new Subtraction<T>();
+      firstOp = new Addition<T>();
+      secondOp = new Addition<T>();
     } else if (name == ";") {
-      op = new Comma<T>();
+      firstOp = new Comma<T>();
+      secondOp = new Comma<T>();
     } else if (name == "GUARD") {
-      op = new Guard<T>();
+      firstOp = new Guard<T>();
+      secondOp = new Guard<T>();
     } else {
       std::cerr << "Unknown leaf node type: " << name << std::endl;
       throw "Unknown leaf node type";
     }
-    return system.newExpression(op, args);
+    return std::pair<Expression<T>*, Expression<T>*>(
+        system.newExpression(firstOp, firstArgs),
+        system.newExpression(secondOp, secondArgs));
   }
 }
 
@@ -82,12 +125,21 @@ void treeToSystem(pANTLR3_BASE_TREE node, EquationSystem<T>& system) {
     varNode = (pANTLR3_BASE_TREE) node->getChild(node, i);
     exprNode = (pANTLR3_BASE_TREE) node->getChild(node, i+1);
 
+    Variable<T>* var;
+    vector<Expression<T>*> args;
+
     string varName = (char*) varNode->getText(varNode)->chars;
-    Variable<T>* var = system.newVariable(varName);
+    std::pair<Expression<T>*, Expression<T>*> exprs = treeToExpression(exprNode, system);
 
-    vector<Expression<T>*> args;
+    var = system.newVariable(varName + "_l");
+    args.push_back(system.newExpression(new Constant<T>(-infinity<T>())));
+    args.push_back(exprs.first);
+    system[*var] = system.newMaxExpression(args);
+
+    args.clear();
+    var = system.newVariable(varName + "_u");
     args.push_back(system.newExpression(new Constant<T>(-infinity<T>())));
-    args.push_back(treeToExpression(exprNode, system));
+    args.push_back(exprs.second);
     system[*var] = system.newMaxExpression(args);
   }
 }
-- 
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