[string] Migrate String.prototype.{split,replace} to TF

src/js/string.js

Index: src/js/string.js
diff --git a/src/js/string.js b/src/js/string.js
index c0587350cd6d4730183398c094c1db517c3c5e3e..1da5c5f766b979353a5e053518f31f41cf7fe635 100644
--- a/src/js/string.js
+++ b/src/js/string.js
@@ -9,21 +9,9 @@
 // -------------------------------------------------------------------
 // Imports
 
-var ArrayJoin;
-var GlobalRegExp = global.RegExp;
 var GlobalString = global.String;
-var MaxSimple;
-var MinSimple;
 var matchSymbol = utils.ImportNow("match_symbol");
-var replaceSymbol = utils.ImportNow("replace_symbol");
 var searchSymbol = utils.ImportNow("search_symbol");
-var splitSymbol = utils.ImportNow("split_symbol");
-
-utils.Import(function(from) {
-  ArrayJoin = from.ArrayJoin;
-  MaxSimple = from.MaxSimple;
-  MinSimple = from.MinSimple;
-});
 
 //-------------------------------------------------------------------
 
@@ -58,154 +46,6 @@ function StringMatchJS(pattern) {
   return regexp[matchSymbol](subject);
 }
 
-// ES#sec-getsubstitution
-// GetSubstitution(matched, str, position, captures, replacement)
-// Expand the $-expressions in the string and return a new string with
-// the result.
-function GetSubstitution(matched, string, position, captures, replacement) {
-  var matchLength = matched.length;
-  var stringLength = string.length;
-  var capturesLength = captures.length;
-  var tailPos = position + matchLength;
-  var result = "";
-  var pos, expansion, peek, next, scaledIndex, advance, newScaledIndex;
-
-  var next = %StringIndexOf(replacement, '$', 0);
-  if (next < 0) {
-    result += replacement;
-    return result;
-  }
-
-  if (next > 0) result += %_SubString(replacement, 0, next);
-
-  while (true) {
-    expansion = '$';
-    pos = next + 1;
-    if (pos < replacement.length) {
-      peek = %_StringCharCodeAt(replacement, pos);
-      if (peek == 36) {         // $$
-        ++pos;
-        result += '$';
-      } else if (peek == 38) {  // $& - match
-        ++pos;
-        result += matched;
-      } else if (peek == 96) {  // $` - prefix
-        ++pos;
-        result += %_SubString(string, 0, position);
-      } else if (peek == 39) {  // $' - suffix
-        ++pos;
-        result += %_SubString(string, tailPos, stringLength);
-      } else if (peek >= 48 && peek <= 57) {
-        // Valid indices are $1 .. $9, $01 .. $09 and $10 .. $99
-        scaledIndex = (peek - 48);
-        advance = 1;
-        if (pos + 1 < replacement.length) {
-          next = %_StringCharCodeAt(replacement, pos + 1);
-          if (next >= 48 && next <= 57) {
-            newScaledIndex = scaledIndex * 10 + ((next - 48));
-            if (newScaledIndex < capturesLength) {
-              scaledIndex = newScaledIndex;
-              advance = 2;
-            }
-          }
-        }
-        if (scaledIndex != 0 && scaledIndex < capturesLength) {
-          var capture = captures.at(scaledIndex);
-          if (!IS_UNDEFINED(capture)) result += capture;
-          pos += advance;
-        } else {
-          result += '$';
-        }
-      } else {
-        result += '$';
-      }
-    } else {
-      result += '$';
-    }
-
-    // Go the the next $ in the replacement.
-    next = %StringIndexOf(replacement, '$', pos);
-
-    // Return if there are no more $ characters in the replacement. If we
-    // haven't reached the end, we need to append the suffix.
-    if (next < 0) {
-      if (pos < replacement.length) {
-        result += %_SubString(replacement, pos, replacement.length);
-      }
-      return result;
-    }
-
-    // Append substring between the previous and the next $ character.
-    if (next > pos) {
-      result += %_SubString(replacement, pos, next);
-    }
-  }
-  return result;
-}
-
-// ES6, section 21.1.3.14
-function StringReplace(search, replace) {
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.replace");
-
-  // Decision tree for dispatch
-  // .. regexp search (in src/js/regexp.js, RegExpReplace)
-  // .... string replace
-  // ...... non-global search
-  // ........ empty string replace
-  // ........ non-empty string replace (with $-expansion)
-  // ...... global search
-  // ........ no need to circumvent last match info override
-  // ........ need to circument last match info override
-  // .... function replace
-  // ...... global search
-  // ...... non-global search
-  // .. string search
-  // .... special case that replaces with one single character
-  // ...... function replace
-  // ...... string replace (with $-expansion)
-
-  if (!IS_NULL_OR_UNDEFINED(search)) {
-    var replacer = search[replaceSymbol];
-    if (!IS_UNDEFINED(replacer)) {
-      return %_Call(replacer, search, this, replace);
-    }
-  }
-
-  var subject = TO_STRING(this);
-
-  search = TO_STRING(search);
-
-  if (search.length == 1 &&
-      subject.length > 0xFF &&
-      IS_STRING(replace) &&
-      %StringIndexOf(replace, '$', 0) < 0) {
-    // Searching by traversing a cons string tree and replace with cons of
-    // slices works only when the replaced string is a single character, being
-    // replaced by a simple string and only pays off for long strings.
-    return %StringReplaceOneCharWithString(subject, search, replace);
-  }
-  var start = %StringIndexOf(subject, search, 0);
-  if (start < 0) return subject;
-  var end = start + search.length;
-
-  var result = %_SubString(subject, 0, start);
-
-  // Compute the string to replace with.
-  if (IS_CALLABLE(replace)) {
-    result += replace(search, start, subject);
-  } else {
-    // In this case, we don't have any capture groups and can get away with
-    // faking the captures object by simply setting its length to 1.
-    const captures = { length: 1 };
-    const matched = %_SubString(subject, start, end);
-    result += GetSubstitution(matched, subject, start, captures,
-                              TO_STRING(replace));
-  }
-
-  return result + %_SubString(subject, end, subject.length);
-}
-
-
 // ES6 21.1.3.15.
 function StringSearch(pattern) {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.search");
@@ -266,39 +106,6 @@ function StringSlice(start, end) {
   return %_SubString(s, start_i, end_i);
 }
 
-
-// ES6 21.1.3.17.
-function StringSplitJS(separator, limit) {
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.split");
-
-  if (!IS_NULL_OR_UNDEFINED(separator)) {
-    var splitter = separator[splitSymbol];
-    if (!IS_UNDEFINED(splitter)) {
-      return %_Call(splitter, separator, this, limit);
-    }
-  }
-
-  var subject = TO_STRING(this);
-  limit = (IS_UNDEFINED(limit)) ? kMaxUint32 : TO_UINT32(limit);
-
-  var length = subject.length;
-  var separator_string = TO_STRING(separator);
-
-  if (limit === 0) return [];
-
-  // ECMA-262 says that if separator is undefined, the result should
-  // be an array of size 1 containing the entire string.
-  if (IS_UNDEFINED(separator)) return [subject];
-
-  var separator_length = separator_string.length;
-
-  // If the separator string is empty then return the elements in the subject.
-  if (separator_length === 0) return %StringToArray(subject, limit);
-
-  return %StringSplit(subject, separator_string, limit);
-}
-
-
 // ECMA-262, 15.5.4.16
 function StringToLowerCaseJS() {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.toLowerCase");
@@ -515,10 +322,8 @@ utils.InstallFunctions(GlobalString.prototype, DONT_ENUM, [
   "concat", StringConcat,
   "match", StringMatchJS,
   "repeat", StringRepeat,
-  "replace", StringReplace,
   "search", StringSearch,
   "slice", StringSlice,
-  "split", StringSplitJS,
   "toLowerCase", StringToLowerCaseJS,
   "toLocaleLowerCase", StringToLocaleLowerCase,
   "toUpperCase", StringToUpperCaseJS,
@@ -539,14 +344,4 @@ utils.InstallFunctions(GlobalString.prototype, DONT_ENUM, [
   "sup", StringSup
 ]);
 
-// -------------------------------------------------------------------
-// Exports
-
-utils.Export(function(to) {
-  to.StringMatch = StringMatchJS;
-  to.StringReplace = StringReplace;
-  to.StringSlice = StringSlice;
-  to.StringSplit = StringSplitJS;
-});
-
 })