add simple algorithm flawed example for bracketing,

Example: https://www.diffchecker.com/OWtBlP0x
add blockWrap function

lib/preprocessor.js

@@ -1,6 +1,16 @@
 const SolExplore = require('sol-explore');
 const SolidityParser = require('solidity-parser-sc');
 
+/**
+ * Splices enclosing brackets into `contract` around `expression`;
+ * @param  {String} contract   solidity source
+ * @param  {Object} expression AST node to bracket
+ * @return {String}            contract
+ */
+function blockWrap(contract, expression) {
+  return contract.slice(0, expression.start) + '{' + contract.slice(expression.start, expression.end) + '}' + contract.slice(expression.end);
+}
+
 /**
  * Parses the AST tree to remove pure, constant and view modifiers
  * @param  {Object} ast      AST tree
@@ -34,6 +44,7 @@ function removeViewPureConst(ast, contract) {
  */
 function bracketUnbStatements(ast, contract) {
   const brkList = [];
+  let offset = 0;
   SolExplore.traverse(ast, {
     enter(node, parent) { // eslint-disable-line no-loop-func
       // If consequents
@@ -83,6 +94,11 @@ function bracketUnbStatements(ast, contract) {
       check = brkList[i].end <= brkList[i - 1].end;
     }
     brkList[i].nested = check;
+    const elem = Object.assign(brkList[i]);
+    elem.start += offset;
+    elem.end += offset;
+    contract = blockWrap(contract, elem);
+    offset += 2;
   }
   return contract;
 }