+ result_valid = false;
+}
+
+void ProgramCompiler::ExpressionEvaluator::visit(BinaryExpression &binary)
+{
+ result_valid = false;
+ binary.left->visit(*this);
+ if(!result_valid)
+ return;
+
+ float left_result = result;
+ result_valid = false;
+ binary.right->visit(*this);
+ if(!result_valid)
+ return;
+
+ if(binary.oper=="<")
+ result = (left_result<result);
+ else if(binary.oper=="<=")
+ result = (left_result<=result);
+ else if(binary.oper==">")
+ result = (left_result>result);
+ else if(binary.oper==">=")
+ result = (left_result>=result);
+ else if(binary.oper=="==")
+ result = (left_result==result);
+ else if(binary.oper=="!=")
+ result = (left_result!=result);
+ else if(binary.oper=="&&")
+ result = (left_result && result);
+ else if(binary.oper=="||")
+ result = (left_result || result);
+ else
+ result_valid = false;
+}
+
+
+ProgramCompiler::ConstantConditionEliminator::ConstantConditionEliminator():
+ scope_level(0)
+{ }
+
+void ProgramCompiler::ConstantConditionEliminator::visit(Block &block)
+{
+ SetForScope<unsigned> set(scope_level, scope_level+1);
+ BlockModifier::visit(block);
+
+ for(map<string, VariableDeclaration *>::const_iterator i=block.variables.begin(); i!=block.variables.end(); ++i)
+ variable_values.erase(i->second);
+}