Fix luis converter to enable escaping specific chars

packages/lu/src/parser/lufile/visitor.js

@@ -12,7 +12,7 @@ class Visitor {
         let utterance = '';
         let entities = [];
         let errorMsgs = [];
-        for (const node of ctx.children) {
+        for (const [index, node] of ctx.children.entries()) {
             const innerNode = node;
             switch (innerNode.symbol.type) {
                 case lp.DASH: break;
@@ -23,7 +23,7 @@ class Visitor {
                 }
                 case lp.ESCAPE_CHARACTER: {
                     let escapeCharacters = innerNode.getText();
-                    let escapedUtterace = escapeCharacters.length > 1 && EscapeCharsInUtterance.includes(escapeCharacters[1]) ? escapeCharacters.slice(1) : escapeCharacters;
+                    let escapedUtterace = escapeCharacters.length > 1 && (EscapeCharsInUtterance.includes(escapeCharacters[1]) || (escapeCharacters[1] === '\\' && index + 1 < ctx.children.length && ctx.children[index + 1].symbol.type === lp.EXPRESSION)) ? escapeCharacters.slice(1) : escapeCharacters;
                     utterance = utterance.concat(escapedUtterace);
                     break;
                 }
@@ -98,7 +98,8 @@ class Visitor {
         let expChars = exp.split('');
         let escapeChar = false;
         expChars.forEach(function (char, index) {
-            if (char === '\\' && expChars.length > index + 1 && EscapeCharsInUtterance.includes(expChars[index + 1])) {
+            if (char === '\\' && !escapeChar && expChars.length > index + 1
+                && (EscapeCharsInUtterance.includes(expChars[index + 1]) || expChars[index + 1] === '\\')) {
                 escapeChar = true;
             } else if (char === '{' && !escapeChar) {
                 let newEntity = {entityName : '', role : '', entityValue : undefined, parent : curEntity};

packages/lu/src/parser/luis/luConverter.js

@@ -1,6 +1,8 @@
 const NEWLINE = require('os').EOL;
 const helperClasses = require('./../lufile/classes/hclasses')
 const EntityTypeEnum = require('./../utils/enums/luisEntityTypes');
+const EscapeCharsInUtterance = require('./../utils/enums/escapechars').EscapeCharsInUtterance;
+const helpers = require('./../utils/helpers');
 
 /**
  * Parses a Luis object into Lu Content
@@ -89,7 +91,7 @@ const parseUtterancesToLu = function(utterances, luisJSON){
         if(luisJSON.test === true && utterance.predictedResult !== undefined){
             fileContent += parsePredictedResultToLu(utterance, luisJSON)
         }
-        if(utterance.entities.length >= 0) {
+        if(utterance.entities.length > 0) {
             // update utterance for each entity
             let text = utterance.text;
             // flatten entities
@@ -99,10 +101,25 @@ const parseUtterancesToLu = function(utterances, luisJSON){
             // remove all children
             sortedEntitiesList.forEach(entity => delete entity.children);
             let tokenizedText = text.split('');
+            tokenizedText.forEach(function (token, index) {
+                tokenizedText[index] = EscapeCharsInUtterance.includes(token) ? `\\${token}` : token; 
+            });
             // handle cases where we have both child as well as cases where more than one entity can have the same start position
             // if there are multiple entities in the same start position, then order them by composite, nDepth, regular entity
             getEntitiesByPositionList(sortedEntitiesList, tokenizedText);
             updatedText = tokenizedText.join('');
+        } else {
+            // will not add escape char for pattern utterances since brackets are strictly used in pattern
+            // so there are no exceptions that need to be handled in pattern
+            if (helpers.isUtterancePattern(utterance)) {
+                updatedText = utterance.text;
+            } else {
+                let tokenizedText = utterance.text.split('');
+                tokenizedText.forEach(function (token, index) {
+                    tokenizedText[index] = EscapeCharsInUtterance.includes(token) ? `\\${token}` : token;
+                });
+                updatedText = tokenizedText.join('');
+            }
         }
 
         // remove duplicated whitespaces between words inside utterance to make sure they are aligned with the luis portal
@@ -138,7 +155,16 @@ const updateTokenizedTextByEntity = function(tokenizedText, entity) {
     } else {
         tokenizedText[parseInt(entity.startPos)] = `{@${entity.entity}=${tokenizedText[parseInt(entity.startPos)]}`;    
     }
-    tokenizedText[parseInt(entity.endPos)] = tokenizedText[parseInt(entity.endPos)] + '}';
+
+    // check blackslash before entity definition
+    // blackslash before { or } will be reconized to escape { or }
+    // to avoid such escape, add another blackslash before blackslash
+    if (parseInt(entity.startPos) > 0 && tokenizedText[parseInt(entity.startPos) - 1] === '\\') {
+        tokenizedText[parseInt(entity.startPos) - 1] += '\\'
+    }
+
+    tokenizedText[parseInt(entity.endPos)] = tokenizedText[parseInt(entity.endPos)] === '\\' ? 
+        tokenizedText[parseInt(entity.endPos)] + '\\}' : tokenizedText[parseInt(entity.endPos)] + '}';
 }
 
 const parsePredictedResultToLu =  function(utterance, luisJSON){

packages/lu/src/parser/utils/enums/escapechars.js

@@ -4,5 +4,5 @@
  */
  // Escape chars in utterance
 module.exports = {
-    EscapeCharsInUtterance: ['{', '}', '\\']
+    EscapeCharsInUtterance: ['{', '}']
 };

packages/lu/test/commands/luis/convert.test.js

@@ -62,6 +62,14 @@ describe('luis:convert', () => {
         await assertToLu('./../../fixtures/verified/nDepthEntityInUtterance.json', './../../fixtures/verified/nDepthEntityInUtterance.lu')
     })
 
+    it('luis:convert successfully reconstructs a markdown file from a LUIS input file (with escape characters in utterances)', async () => {
+        await assertToLu('./../../fixtures/verified/escapeCharactersInUtterances.json', './../../fixtures/verified/escapeCharactersInUtterances.lu')
+    })
+
+    it('luis:convert Utterances with escape characters correctly', async () => {
+        await assertToJSON('./../../fixtures/verified/escapeCharactersInUtterances.lu', './../../fixtures/verified/escapeCharactersInUtterances.json')
+    })
+
     it('luis:convert Simple intent and utterances are parsed correctly', async () => {
         await assertToJSON('./../../fixtures/examples/1.lu', './../../fixtures/verified/1.json', '1')
     })