feat(stdlib): Add addCharFromCodePoint to Buffer module (#1883)

Co-authored-by: Oscar Spencer <oscar.spen@gmail.com>

Author: spotandjake

compiler/test/stdlib/buffer.test.gr

@@ -5,6 +5,7 @@ include "string"
 include "buffer"
 include "bytes"
 include "int32"
+include "char"
 
 // it should have 0 length when buffer is created
 assert Buffer.length(Buffer.make(0)) == 0
@@ -320,6 +321,24 @@ let buf = Buffer.make(0)
 Buffer.addChar(char, buf)
 assert Buffer.toString(buf) == "🍞"
 
+// addCharFromCodePoint
+let char = Char.code('a') // 1 byte
+let buf = Buffer.make(0)
+Buffer.addCharFromCodePoint(char, buf)
+assert Buffer.toString(buf) == "a"
+let char = Char.code('©') // 2 bytes
+let buf = Buffer.make(0)
+Buffer.addCharFromCodePoint(char, buf)
+assert Buffer.toString(buf) == "©"
+let char = Char.code('✨') // 3 bytes
+let buf = Buffer.make(0)
+Buffer.addCharFromCodePoint(char, buf)
+assert Buffer.toString(buf) == "✨"
+let char = Char.code('🍞') // 4 bytes
+let buf = Buffer.make(0)
+Buffer.addCharFromCodePoint(char, buf)
+assert Buffer.toString(buf) == "🍞"
+
 // addBuffer
 let buf0 = Buffer.make(0)
 Buffer.addString("✨", buf0)

stdlib/buffer.gr

@@ -322,6 +322,18 @@ provide let addChar = (char, buffer) => {
   addString(Char.toString(char), buffer)
 }
 
+/**
+ * Appends a character represented by a code point to a buffer.
+ *
+ * @param codePoint: The code point to append to the buffer
+ * @param buffer: The buffer to mutate
+ *
+ * @since v0.6.0
+ */
+provide let addCharFromCodePoint = (codePoint: Number, buffer) => {
+  addChar(Char.fromCode(codePoint), buffer)
+}
+
 /**
  * Appends the bytes of a subset of a string to a buffer.
  *

stdlib/buffer.md

@@ -331,6 +331,26 @@ Parameters:
 |`char`|`Char`|The character to append to the buffer|
 |`buffer`|`Buffer`|The buffer to mutate|
 
+### Buffer.**addCharFromCodePoint**
+
+<details disabled>
+<summary tabindex="-1">Added in <code>next</code></summary>
+No other changes yet.
+</details>
+
+```grain
+addCharFromCodePoint : (codePoint: Number, buffer: Buffer) => Void
+```
+
+Appends a character represented by a code point to a buffer.
+
+Parameters:
+
+|param|type|description|
+|-----|----|-----------|
+|`codePoint`|`Number`|The code point to append to the buffer|
+|`buffer`|`Buffer`|The buffer to mutate|
+
 ### Buffer.**addStringSlice**
 
 <details>