Merge pull request #5819 from heshanpadmasiri/feat/backtick-template

Improve the explanation about backtick templates

examples/index.json

@@ -455,7 +455,7 @@
     "title": "Equality",
     "column": 0,
     "category": "Language concepts",
-    "samples": [ 
+    "samples": [
       {
         "name": "Expression equality",
         "url": "expression-equality",
@@ -1099,15 +1099,13 @@
       {
         "name": "Raw templates",
         "url": "raw-templates",
-        "verifyBuild": false,
-        "verifyOutput": false,
-        "disableVerificationReason": "Includes ballerinax components",
-        "disablePlayground": true,
+        "verifyBuild": true,
+        "verifyOutput": true,
         "isLearnByExample": true
       },
       {
-        "name": "Backtick templates",
-        "url": "backtick-templates",
+        "name": "String templates",
+        "url": "string-templates",
         "verifyBuild": true,
         "verifyOutput": true,
         "isLearnByExample": true

examples/raw-templates/raw_templates.md

@@ -11,6 +11,7 @@ An important use case of custom raw templates is SQL parameterized queries.
 ::: out raw_templates.out :::
 
 ## Related links
-- [Backtick templates](https://ballerina.io/learn/by-example/backtick-templates/)
+- [String templates](https://ballerina.io/learn/by-example/string-templates/)
+- [RegExp type](https://ballerina.io/learn/by-example/regexp-type/)
 - [Object type inclusion](https://ballerina.io/learn/by-example/object-type-inclusion/)
 - [Database Access - Simple query](https://ballerina.io/learn/by-example/mysql-query-operation/)

examples/string-templates/string_templates.bal

@@ -0,0 +1,30 @@
+import ballerina/io;
+
+public function main() {
+    string word = "world";
+    string s0 = string `Hello, ${word}!`;
+    io:println(s0);
+
+    // Use interpolations to use escape characters.
+    // Note how the first `\n` is treated as is.
+    string s1 = string `line one \n rest of line 1 ${"\n"} second line`;
+    io:println(s1);
+
+    // Use interpolations to add the ` and  $ characters.
+    string s2 = string `Backtick: ${"`"} Dollar: ${"$"}`;
+    io:println(s2);
+
+    // A string template expression can be written on multiple lines by breaking at interpolations.
+    string s3 = string `T_1 is ${
+                1}, T_2 is ${1 +
+                2} and T_3 is ${1 + 2 + 3
+                }`;
+    io:println(s3);
+
+    // If there are no interpolations to break at a required point, you can introduce an interpolation with an empty
+    // string.
+    string s4 = string `prefix ${
+                ""}middle ${""
+                }suffix`;
+    io:println(s4);
+}

examples/string-templates/string_templates.md

@@ -0,0 +1,3 @@
+# String templates
+
+A string template is a template expression that can be used to create a string literal. It consists of the `string` tag and a sequence of characters interleaved with interpolations (in the form `${expression}`). Each interpolation must be a subtype of `boolean|int|float|decimal|string`. Every character not a part of the interpolation is interpreted as is to form a sequence of string literals broken at interpolations. This means if you want to add any escape characters you must add them as interpolations (for example `${"\n"}`). Every interpolation is converted to a string using the `toString` lang lib function and concatenated with the other string literals to form a single string literal.

examples/string-templates/string_templates.metatags

@@ -0,0 +1,2 @@
+description: This BBE demonstrates string templates in Ballerina.
+keywords: ballerina, ballerina by example, bbe, string templates

examples/string-templates/string_templates.out

@@ -0,0 +1,7 @@
+$ bal run string_templates.bal
+Hello, world!
+line one \n rest of line 1 
+ second line
+Backtick: ` Dollar: $
+T_1 is 1, T_2 is 3 and T_3 is 6
+prefix middle suffix