From fcecd0e7dc0bf103986c02e2f29fb518cd5571c5 Mon Sep 17 00:00:00 2001
From: Carlo Zancanaro <carlo@carlo-laptop>
Date: Thu, 3 May 2012 15:35:39 +1000
Subject: Add a parser for linear equations

(Also add the antlr jar and C runtime)
---
 impl/main.cpp | 138 ++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 87 insertions(+), 51 deletions(-)

(limited to 'impl/main.cpp')

diff --git a/impl/main.cpp b/impl/main.cpp
index a0c6bea..c5a0be6 100644
--- a/impl/main.cpp
+++ b/impl/main.cpp
@@ -1,5 +1,8 @@
 #include <iostream>
 #include <vector>
+#include <map>
+#include <string>
+#include <sstream>
 #include <math.h>
 
 #include "Operator.hpp"
@@ -7,6 +10,11 @@
 #include "MaxStrategy.hpp"
 #include "EquationSystem.hpp"
 
+extern "C" {
+#include "EquationSystemParser.h"
+#include "EquationSystemLexer.h"
+}
+
 using namespace std;
 
 typedef std::vector<Expression<float>*> Args;
@@ -15,66 +23,94 @@ typedef Constant<float> C;
 typedef Addition<float> A;
 typedef Minimum<float> Min;
 
-std::vector< Expression<float>* > empty;
-int main () {
-  {
-  EquationSystem<float> sys;
-  Variable<float>* x = sys.newVariable("x");
-  Variable<float>* y = sys.newVariable("y");
-  Variable<float>* z = sys.newVariable("z");
-
-  Args xPlusArgs;
-  xPlusArgs.push_back(sys.newExpression(x, empty));
-
-  Args xMinArgs;
-  xMinArgs.push_back(sys.newExpression(new A(-1), xPlusArgs));
-  xMinArgs.push_back(sys.newExpression(y, empty));
-
-  Args xMaxArgs;
-  xMaxArgs.push_back(sys.newExpression(new C(0), empty));
-  xMaxArgs.push_back(sys.newExpression(new Min(), xMinArgs));
-
-  sys[*x] = sys.newMaxExpression(xMaxArgs);
-  // x = max(0, min(x-1, y))
-
-
-  Args yPlusArgs;
-  yPlusArgs.push_back(sys.newExpression(x, empty));
-
-  Args yMaxArgs;
-  yMaxArgs.push_back(sys.newExpression(new C(0), empty));
-  yMaxArgs.push_back(sys.newExpression(new A(5), yPlusArgs));
-  yMaxArgs.push_back(sys.newExpression(x, empty));
-
-  sys[*y] = sys.newMaxExpression(yMaxArgs);
-  // y = max(0, x+5, x)
+template<typename T>
+Expression<T>* treeToExpression(pANTLR3_BASE_TREE node, EquationSystem<T>& system) {
+  ANTLR3_UINT32 num = node->getChildCount(node);
+
+  string name = (char*) node->getText(node)->chars;
+
+  // leaf node - constant or variable
+  if (num == 0) {
+    stringstream stream(name);
+    T output;
+    if (stream >> output) {
+      return system.newExpression(new Constant<T>(output), vector<Expression<T>*>());
+    } else {
+      return system.newExpression(system.newVariable(name), vector<Expression<T>*>());
+    }
+  }
 
+  // other operators
+  std::vector<Expression<T>*> args;
+  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));
+  }
 
-  Args zPlusArgs1;
-  zPlusArgs1.push_back(sys.newExpression(z, empty));
+  if (name == "max") {
+    return system.newMaxExpression(args);
+  } else {
+    Operator<T>* op = NULL;
+    if (name == "min") {
+      op = new Minimum<T>();
+    } else if (name == "+") {
+      op = new Addition<T>();
+    } else if (name == "-") {
+      op = new Subtraction<T>();
+    }
+    return system.newExpression(op, args);
+  }
+}
 
-  Args zPlusArgs2;
-  zPlusArgs2.push_back(sys.newExpression(x, empty));
+template<typename T>
+void treeToSystem(pANTLR3_BASE_TREE node, EquationSystem<T>& system) {
+  ANTLR3_UINT32 num = node->getChildCount(node);
 
-  Args zMaxArgs;
-  zMaxArgs.push_back(sys.newExpression(new C(0), empty));
-  zMaxArgs.push_back(sys.newExpression(new A(1), zPlusArgs1));
-  zMaxArgs.push_back(sys.newExpression(new A(0), zPlusArgs2));
+  if (num % 2 == 1)
+    throw "Big problem here.";
 
-  sys[*z] = sys.newMaxExpression(zMaxArgs);
-  // z = max(0, z+1, x)
+  pANTLR3_BASE_TREE varNode;
+  pANTLR3_BASE_TREE exprNode;
+  for (unsigned int i = 0; i < num; i += 2) {
+    varNode = (pANTLR3_BASE_TREE) node->getChild(node, i);
+    exprNode = (pANTLR3_BASE_TREE) node->getChild(node, i+1);
 
+    string varName = (char*) varNode->getText(varNode)->chars;
+    Variable<T>* var = system.newVariable(varName);
 
+    system[*var] = treeToExpression(exprNode, system);
+  }
+}
 
-  // x = max(0, min(x-1, y))
-  // y = max(0, x+5, x)
-  // z = max(0, z+1, x)
-  // => x: 0, y: 5, z: inf
-  VariableAssignment<float> fixpoint = sys.minFixpoint();
-  cout << "x = " << fixpoint[*x] << endl;
-  cout << "y = " << fixpoint[*y] << endl;
-  cout << "z = " << fixpoint[*z] << endl;
+std::vector< Expression<float>* > empty;
+int main (int argc, char* argv[]) {
+  pANTLR3_INPUT_STREAM input;
+  pEquationSystemLexer lex;
+  pANTLR3_COMMON_TOKEN_STREAM tokens;
+  pEquationSystemParser parser;
+
+  input = antlr3FileStreamNew((pANTLR3_UINT8)argv[1], ANTLR3_ENC_8BIT);
+  lex = EquationSystemLexerNew(input);
+  tokens = antlr3CommonTokenStreamSourceNew(ANTLR3_SIZE_HINT, TOKENSOURCE(lex));
+  parser = EquationSystemParserNew(tokens);
+
+  EquationSystemParser_equation_system_return ret = parser -> equation_system(parser);
+
+  EquationSystem<float> system;
+  treeToSystem<float>(ret.tree, system);
+  // DO MORE HERE
+
+  VariableAssignment<float> rho = system.minFixpoint();
+  const std::vector<Variable<float>*> vars = system.vars();
+  for (unsigned int i = 0, size = vars.size(); i < size; ++i) {
+    cout << vars[i]->name() << " = " << rho[*vars[i]] << endl;
   }
 
+  parser -> free(parser);
+  tokens -> free(tokens);
+  lex -> free(lex);
+  input -> close(input);
+
   return 0;
 }
-- 
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