feat(stdlib): Add charCodeAt function to String module (#1376)

Author: spotandjake

compiler/test/stdlib/string.test.gr

@@ -81,6 +81,12 @@ assert String.lastIndexOf(emoji, emojis) == None
 assert String.lastIndexOf("aa", "aaa") == Some(1)
 assert String.lastIndexOf("world", "Hello world world") == Some(12)
 
+// charCodeAt tests
+assert String.charCodeAt(0, emojis) == 119
+assert String.charCodeAt(15, emojis) == 128640
+assert String.charCodeAt(16, emojis) == 32
+assert String.charCodeAt(17, emojis) == 116
+
 // charAt tests
 assert String.charAt(0, emojis) == 'w'
 assert String.charAt(15, emojis) == '🚀'

stdlib/string.gr

@@ -281,19 +281,9 @@ let getCodePoint = (ptr: WasmI32) => {
   }
   result
 }
-/**
- * Get the character at the position in the input string.
- *
- * @param position: The position to check
- * @param string: The string to search
- * @returns The character at the provided position
- *
- * @example String.charAt(5, "Hello world") == ' '
- *
- * @since v0.4.0
- */
+
 @unsafe
-export let charAt = (position, string: String) => {
+let charAtHelp = (position, string: String) => {
   if (length(string) <= position || position < 0) {
     fail "Invalid offset: " ++ toString(position)
   }
@@ -309,10 +299,10 @@ export let charAt = (position, string: String) => {
   let mut ptr = string + 8n
   let end = ptr + size
   let mut counter = 0n
-  let mut result = WasmI32.toGrain(0n): Char
+  let mut result = 0n
   while (ptr < end) {
     if (counter == position) {
-      result = tagChar(getCodePoint(ptr))
+      result = getCodePoint(ptr)
       break
     }
     let byte = WasmI32.load8U(ptr, 0n)
@@ -334,6 +324,38 @@ export let charAt = (position, string: String) => {
   result
 }
 
+/**
+ * Get the Unicode code point at the position in the input string.
+ *
+ * @param position: The position to check
+ * @param string: The string to search
+ * @returns The character code at the provided position
+ *
+ * @example String.charCodeAt(5, "Hello world") == 32
+ *
+ * @since v0.5.3
+ */
+@unsafe
+export let charCodeAt = (position, string: String) => {
+  tagSimpleNumber(charAtHelp(position, string))
+}
+
+/**
+ * Get the character at the position in the input string.
+ *
+ * @param position: The position to check
+ * @param string: The string to search
+ * @returns The character at the provided position
+ *
+ * @example String.charAt(5, "Hello world") == ' '
+ *
+ * @since v0.4.0
+ */
+@unsafe
+export let charAt = (position, string: String) => {
+  tagChar(charAtHelp(position, string))
+}
+
 @unsafe
 let explodeHelp = (s: String, chars) => {
   let (>>>) = WasmI32.shrU

stdlib/string.md

@@ -201,6 +201,38 @@ Examples:
 String.lastIndexOf("world", "Hello world world") == Some(12)
 ```
 
+### String.**charCodeAt**
+
+<details disabled>
+<summary tabindex="-1">Added in <code>next</code></summary>
+No other changes yet.
+</details>
+
+```grain
+charCodeAt : (Number, String) -> Number
+```
+
+Get the Unicode code point at the position in the input string.
+
+Parameters:
+
+|param|type|description|
+|-----|----|-----------|
+|`position`|`Number`|The position to check|
+|`string`|`String`|The string to search|
+
+Returns:
+
+|type|description|
+|----|-----------|
+|`Number`|The character code at the provided position|
+
+Examples:
+
+```grain
+String.charCodeAt(5, "Hello world") == 32
+```
+
 ### String.**charAt**
 
 <details disabled>