Split and replace in wren.

src/vm/wren_core.wren

@@ -132,6 +132,57 @@ class String is Sequence {
   bytes { StringByteSequence.new(this) }
   codePoints { StringCodePointSequence.new(this) }
 
+  split(delim) {
+    if (!(delim is String) || delim.isEmpty) {
+      Fiber.abort("Argument must be a non-empty string.")
+    }
+
+    var result = []
+
+    var last = 0
+    var index = 0
+
+    var delimSize = delim.byteCount_
+    var size = byteCount_
+
+    while (last < size && (index = indexOf(delim, last)) != -1) {
+      result.add(this[last...index])
+      last = index + delimSize
+    }
+
+    if (last < size) {
+      result.add(this[last..-1])
+    } else {
+      result.add("")
+    }
+    return result
+  }
+
+  replace(from, to) {
+    if (!(from is String) || from.isEmpty) {
+      Fiber.abort("From must be a non-empty string.")
+    } else if (!(to is String)) {
+      Fiber.abort("To must be a string.")
+    }
+
+    var result = ""
+
+    var last = 0
+    var index = 0
+
+    var fromSize = from.byteCount_
+    var size = byteCount_
+
+    while (last < size && (index = indexOf(from, last)) != -1) {
+      result = result + this[last...index] + to
+      last = index + fromSize
+    }
+
+    if (last < size) result = result + this[last..-1]
+
+    return result
+  }
+
   *(count) {
     if (!(count is Num) || !count.isInteger || count < 0) {
       Fiber.abort("Count must be a non-negative integer.")

src/vm/wren_core.wren.inc

@@ -134,6 +134,57 @@ static const char* coreModuleSource =
 "  bytes { StringByteSequence.new(this) }\n"
 "  codePoints { StringCodePointSequence.new(this) }\n"
 "\n"
+"  split(delim) {\n"
+"    if (!(delim is String) || delim.isEmpty) {\n"
+"      Fiber.abort(\"Argument must be a non-empty string.\")\n"
+"    }\n"
+"\n"
+"    var result = []\n"
+"\n"
+"    var last = 0\n"
+"    var index = 0\n"
+"\n"
+"    var delimSize = delim.byteCount_\n"
+"    var size = byteCount_\n"
+"\n"
+"    while (last < size && (index = indexOf(delim, last)) != -1) {\n"
+"      result.add(this[last...index])\n"
+"      last = index + delimSize\n"
+"    }\n"
+"\n"
+"    if (last < size) {\n"
+"      result.add(this[last..-1])\n"
+"    } else {\n"
+"      result.add(\"\")\n"
+"    }\n"
+"    return result\n"
+"  }\n"
+"\n"
+"  replace(from, to) {\n"
+"    if (!(from is String) || from.isEmpty) {\n"
+"      Fiber.abort(\"From must be a non-empty string.\")\n"
+"    } else if (!(to is String)) {\n"
+"      Fiber.abort(\"To must be a string.\")\n"
+"    }\n"
+"\n"
+"    var result = \"\"\n"
+"\n"
+"    var last = 0\n"
+"    var index = 0\n"
+"\n"
+"    var fromSize = from.byteCount_\n"
+"    var size = byteCount_\n"
+"\n"
+"    while (last < size && (index = indexOf(from, last)) != -1) {\n"
+"      result = result + this[last...index] + to\n"
+"      last = index + fromSize\n"
+"    }\n"
+"\n"
+"    if (last < size) result = result + this[last..-1]\n"
+"\n"
+"    return result\n"
+"  }\n"
+"\n"
 "  *(count) {\n"
 "    if (!(count is Num) || !count.isInteger || count < 0) {\n"
 "      Fiber.abort(\"Count must be a non-negative integer.\")\n"