Add string manipulation functions: .uppercase, .lowercase, `.capita…

…lize`

stdlib/src/main/kotlin/eu/iamgio/quarkdown/stdlib/Stdlib.kt

@@ -24,6 +24,7 @@ object Stdlib : LibraryExporter {
                     Text +
                     Math +
                     Logical +
+                    String +
                     Logger +
                     Flow +
                     Data +

stdlib/src/main/kotlin/eu/iamgio/quarkdown/stdlib/String.kt

@@ -0,0 +1,38 @@
+package eu.iamgio.quarkdown.stdlib
+
+import eu.iamgio.quarkdown.function.value.wrappedAsValue
+
+/**
+ * `String` stdlib module exporter.
+ * This module handles string manipulation.
+ */
+val String: Module =
+    setOf(
+        ::uppercase,
+        ::lowercase,
+        ::capitalize,
+    )
+
+/**
+ * Converts a string to uppercase.
+ * Example: `Hello, World!` -> `HELLO, WORLD!
+ * @param string string to convert
+ * @return a new uppercase string
+ */
+fun uppercase(string: String) = string.uppercase().wrappedAsValue()
+
+/**
+ * Converts a string to lowercase.
+ * Example: `Hello, World!` -> `hello, world!`
+ * @param string string to convert
+ * @return a new lowercase string
+ */
+fun lowercase(string: String) = string.lowercase().wrappedAsValue()
+
+/**
+ * Capitalizes the first character of a string.
+ * Example: `hello, world!` -> `Hello, world!`
+ * @param string string to capitalize
+ * @return a new string with the first character capitalized
+ */
+fun capitalize(string: String) = string.replaceFirstChar(Char::titlecase).wrappedAsValue()

stdlib/src/main/kotlin/eu/iamgio/quarkdown/stdlib/Text.kt

@@ -13,7 +13,7 @@ import eu.iamgio.quarkdown.misc.color.Color
 
 /**
  * `Text` stdlib module exporter.
- * This module handles text formatting and manipulation.
+ * This module handles text formatting.
  */
 val Text: Module =
     setOf(

test/src/test/kotlin/eu/iamgio/quarkdown/test/FullPipelineTest.kt

@@ -193,6 +193,13 @@ class FullPipelineTest {
             assertEquals("<p>A <div style=\"width: 1.0cm; height: 3.0mm;\"></div> B</p>", it)
         }
 
+        execute("Hello, World! .uppercase {Hello, World!} .lowercase {Hello, World!} .capitalize {hello, world!}") {
+            assertEquals(
+                "<p>Hello, World! HELLO, WORLD! hello, world! Hello, world!</p>",
+                it,
+            )
+        }
+
         execute(
             """
             .doclang {Italian}