support multiple region selection in code snippet

Documentation/spec/docfx_flavored_markdown.md

@@ -84,13 +84,13 @@ Block file inclusion must be in a single line and with no prefix characters befo
 User may need to define section. Mostly used for code table.
 Give an example below.
 
-    > [!div class="tabbedCodeSnippets" data-resources="OutlookServices.Calendar"]
-    > ```cs
-    > <cs code text>
-    > ```
-    > ```javascript
-    > <js code text>
-    > ```
+    [!div class="tabbedCodeSnippets" data-resources="OutlookServices.Calendar"]
+    ```cs
+    <cs code text>
+    ```
+    ```javascript
+    <js code text>
+    ```
 
 The above blockquote Markdown text will transform to section html as in the following:
 ```
@@ -110,8 +110,12 @@ Allows you to insert code with code language specified. The content of specified
 * __`<language>`__ can be made up of any number of character and '-'. However, the recommended value should follow [Highlight.js language names and aliases](http://highlightjs.readthedocs.org/en/latest/css-classes-reference.html#language-names-and-aliases).
 * __`<codepath>`__ is the relative path in file system which indicates the code snippet file that you want to expand.
 * __`<queryoption>`__ and __`<queryoptionvalue>`__ are used together to retrieve part of the code snippet file in the line range or tag name way. We have 2 query string options to represent these two ways:
-    * __`#`__: _`#L{startlinenumber}-L{endlinenumber}`_ (line range) or _`#L{tagname}`_ (tag name)
-    * __`?`__: _`?start={startlinenumber}&end={endlinenumber}`_ (line range) or _`?{name}={tagname}`_ (tag name)
+
+|                          | query string using `#`                 | query string using `?`
+|--------------------------|----------------------------------------|-------------
+| 1. line range            | `#L{startlinenumber}-L{endlinenumber}` | `?start={startlinenumber}&end={endlinenumber}`
+| 2. tagname               | `#{tagname}`                           | `?name={tagname}`
+| 3. multiple region range | _Unsupported_                          | `?range={rangequerystring}`
 * __`<title>`__ can be omitted.
 
 #### Code Snippet Sample
@@ -123,6 +127,7 @@ Allows you to insert code with code language specified. The content of specified
 
 [!code[Main](index.xml?start=5&end=9)]
 [!code-javascript[Main](../jquery.js?name=testsnippet)]
+[!code[Main](index.xml?range=2,5-7,9-) "This includes the lines 2, 5, 6, 7 and lines 9 to the last line"]
 ```
 
 #### Tag Name Representation in Code Snippet Source File

src/Microsoft.DocAsCode.Dfm/CodeSnippetExtractor/CodeSnippet.cs

@@ -3,16 +3,6 @@
 
 namespace Microsoft.DocAsCode.Dfm
 {
-    using System;
-    using System.Collections.Generic;
-
-    public class CodeSnippet
-    {
-        public string Name { get; set; }
-
-        public List<Tuple<int, int>> LinePair { get; set; } 
-    }
-
     public class CodeSnippetTag
     {
         public CodeSnippetTag(string name, int line, CodeSnippetTagType type)

src/Microsoft.DocAsCode.Dfm/CodeSnippetExtractor/CodeSnippetRegexExtractor.cs

@@ -48,7 +48,6 @@ from tag in tagGroup
                         tagResolveResult.StartLine = startLine + 1;
                         tagResolveResult.EndLine = endLine - 1;
                         tagResolveResult.ExcludesLines = excludedLines;
-                        tagResolveResult.IndentLength = DfmCodeExtractorHelper.GetIndentLength(lines[startLine - 1]);
                     }
                     else
                     {

src/Microsoft.DocAsCode.Dfm/CodeSnippetExtractor/DfmTagNameResolveResult.cs

@@ -11,8 +11,6 @@ public class DfmTagNameResolveResult
 
         public int EndLine { get; set; }
 
-        public int IndentLength { get; set; }
-
         public HashSet<int> ExcludesLines { get; set; }
 
         public bool IsSuccessful { get; set; }

src/Microsoft.DocAsCode.Dfm/DfmFencesBlockPathQueryOptions/DfmFencesBlockPathQueryOption.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.DocAsCode.Dfm
+{
+    using System.Collections.Generic;
+
+    public abstract class DfmFencesBlockPathQueryOption : IDfmFencesBlockPathQueryOption
+    {
+        public string ErrorMessage { get; protected set; }
+
+        public abstract bool ValidateAndPrepare(string[] lines, DfmFencesBlockToken token);
+
+        public abstract IEnumerable<string> GetQueryLines(string[] lines);
+
+        protected bool CheckLineRange(int totalLines, int? startLine, int? endLine)
+        {
+            if (startLine == null && endLine == null)
+            {
+                ErrorMessage = "Neither start line nor end line is specified correctly";
+                return false;
+            }
+
+            if (startLine <= 0 || endLine <= 0)
+            {
+                ErrorMessage = "Start/End line should be larger than zero";
+                return false;
+            }
+
+            if (startLine > endLine)
+            {
+                ErrorMessage = $"Start line {startLine} shouldn't be larger than end line {endLine}";
+                return false;
+            }
+
+            if (startLine > totalLines)
+            {
+                ErrorMessage = $"Start line '{startLine}' execeeds total file lines '{totalLines}'";
+                return false;
+            }
+
+            return true;
+        }
+
+    }
+}

src/Microsoft.DocAsCode.Dfm/DfmFencesBlockPathQueryOptions/IDfmFencesBlockPathQueryOption.cs

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.DocAsCode.Dfm
+{
+    using System.Collections.Generic;
+
+    public interface IDfmFencesBlockPathQueryOption
+    {
+        string ErrorMessage { get; }
+
+        bool ValidateAndPrepare(string[] lines, DfmFencesBlockToken token);
+
+        IEnumerable<string> GetQueryLines(string[] lines);
+    }
+}

src/Microsoft.DocAsCode.Dfm/DfmFencesBlockPathQueryOptions/LineRangeBlockPathQueryOption.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.DocAsCode.Dfm
+{
+    using System;
+    using System.Collections.Generic;
+
+    class LineRangeBlockPathQueryOption : DfmFencesBlockPathQueryOption
+    {
+        public int? StartLine { get; set; }
+
+        public int? EndLine { get; set; }
+
+        public override bool ValidateAndPrepare(string[] lines, DfmFencesBlockToken token)
+        {
+            if (!CheckLineRange(lines.Length, StartLine, EndLine))
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        public override IEnumerable<string> GetQueryLines(string[] lines)
+        {
+            int startLine = StartLine ?? 1;
+            int endLine = EndLine ?? lines.Length;
+
+            for (int i = startLine; i <= Math.Min(endLine, lines.Length); i++)
+            {
+                yield return lines[i - 1];
+            }
+        }
+    }
+}

src/Microsoft.DocAsCode.Dfm/DfmFencesBlockPathQueryOptions/MultipleLineRangeBlockPathQueryOption.cs

@@ -0,0 +1,40 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.DocAsCode.Dfm
+{
+    using System;
+    using System.Collections.Generic;
+
+    class MultipleLineRangeBlockPathQueryOption : DfmFencesBlockPathQueryOption
+    {
+        public List<Tuple<int?, int?>> LinePairs { get; set; } = new List<Tuple<int?, int?>>();
+
+        public override bool ValidateAndPrepare(string[] lines, DfmFencesBlockToken token)
+        {
+            foreach (var pair in LinePairs)
+            {
+                if (!CheckLineRange(lines.Length, pair.Item1, pair.Item2))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        public override IEnumerable<string> GetQueryLines(string[] lines)
+        {
+            foreach (var pair in LinePairs)
+            {
+                int startLine = pair.Item1 ?? 1;
+                int endLine = pair.Item2 ?? lines.Length;
+
+                for (int i = startLine; i <= Math.Min(endLine, lines.Length); i++)
+                {
+                    yield return lines[i - 1];
+                }
+            }
+        }
+    }
+}