Support for replace with regexp

core/src/main/java/com/schibsted/spt/data/jslt/impl/BuiltinFunctions.java

@@ -104,6 +104,7 @@ public class BuiltinFunctions {
     functions.put("from-json", new BuiltinFunctions.FromJson());
     functions.put("to-json", new BuiltinFunctions.ToJson());
     functions.put("replace", new BuiltinFunctions.Replace());
+    functions.put("replace-regexp", new BuiltinFunctions.ReplaceRegexp());
     functions.put("trim", new BuiltinFunctions.Trim());
     functions.put("uuid", new BuiltinFunctions.Uuid());
 
@@ -961,6 +962,32 @@ else if (pos < string.length())
     }
   }
 
+  // ===== REPLACE-REGEXP
+
+  public static class ReplaceRegexp extends AbstractRegexpFunction {
+
+    public ReplaceRegexp() {
+      super("replace-regexp", 3, 3);
+    }
+
+    public JsonNode call(JsonNode input, JsonNode[] arguments) {
+      int args = null == arguments ? 0 : arguments.length;
+      if (args != 3) {
+        throw new JsltException("ReplaceRegexp requires 3 arguments, only " + args + " provided!");
+      }
+
+      String string = NodeUtils.toString(arguments[0], true);
+      if (string == null)
+        return NullNode.instance;
+
+      String regexp = NodeUtils.toString(arguments[1], false);
+      String replacement = NodeUtils.toString(arguments[2], false);
+      String result = !string.matches(regexp) ? string : string.replaceAll(regexp, replacement);
+
+      return new TextNode(result);
+    }
+  }
+
   // ===== TRIM
 
   public static class Trim extends AbstractFunction {

core/src/main/java/com/schibsted/spt/data/jslt/parser/ParserImpl.java

@@ -503,7 +503,13 @@ private static String makeString(ParseContext ctx, Token literal) {
         result[pos++] = ch;
       else {
         ch = string.charAt(++ix);
-
+        // special Regexp characters, s. https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html,
+        // "Predefined character classes".
+        if ("dDhHsSvVwW".contains(String.valueOf(ch))) {
+          result[pos++] = '\\';
+          result[pos++] = ch;
+          continue;
+        }
         switch (ch) {
         case '\\': result[pos++] = ch; break;
         case '"': result[pos++] = ch; break;

core/src/test/resources/function-tests.json

@@ -1127,6 +1127,21 @@
       "input" : "\"some text\"",
       "output": "\"\""
    },
+   {
+      "query": "replace-regexp(., \"(\\d{4})-(\\d{2})-(\\d{2})\", \"$2/$3/$1\")",
+      "input" : "\"2019-12-31\"",
+      "output": "\"12/31/2019\""
+   },
+   {
+      "query": "replace-regexp(., \"(?<year>\\d{4})-(?<month>\\d{2})-(?<day>\\d{2})\", \"${day}.${month}.${year}\")",
+      "input" : "\"2019-12-31\"",
+      "output": "\"31.12.2019\""
+   },
+   {
+      "query": "replace-regexp(., \"([a-z]+)\", \"$1\")",
+      "input" : "\"2019-12-31\"",
+      "output" : "\"2019-12-31\""
+   },
    {
       "query": "trim(.)",
       "input" : "\"some text\"",

core/src/test/resources/json-parse-error-tests.json

@@ -1,7 +1,6 @@
 {
     "description" : "Tests that should cause the JSLT parser to declare JSON syntax error.",
     "tests" : [
-        "\" \\d \"",
         "\"\\u\"",
         "\"\\u0\"",
         "\"\\u00\"",

functions.md

@@ -510,6 +510,27 @@ replace("abc def ghi", "[a-z]", "x")  => "xxx xxx xxx"
 replace("abc def ghi", "[a-z]+", "x") => "x x x"
 ```
 
+### _replace-regexp(value, regexp, out) -> string_
+
+Replaces the string in `value` that matches `regexp` with `out`. 
+If `value` is not a string, it's converted to a string, except
+if it is `null`. `regexp` and `out` must be strings.
+
+It is an error for `regexp` ever to match an empty string.
+
+If the `regexp` does not match the input,`out` corresponds to `value`.
+
+Examples:
+
+```
+replace-regexp("2019-12-31", "(\\d{4})-(\\d{2})-(\\d{2})", "$2/$3/$1")
+   => "12/31/2019"
+replace-regexp("2019-12-31", "(?<year>\\d{4})-(?<month>\\d{2})-(?<day>\\d{2})", "${day}.${month}.${year}")
+   => "31.12.2019"
+replace-regexp("2019-12-31", "([a-z]+)", "$1")
+   => "2019-12-31"
+```
+
 ### _trim(string) -> string_
 
 Removes leading and trailing whitespace in the input string. If the