added $match(..) operator

Author: gorenje

README.md

@@ -47,6 +47,7 @@ At the time of writing, this library supports a minimum set of functionality of
 | $keys | Supported |
 | $length | Supported |
 | $map | Supported |
+| $match | Supported |
 | $millis | Supported - including the requirement that multiple calls produce the same value |
 | $now | Supported - including passing value, e.g., `$now($millis())` |
 | $pad | Supported |

src/erlang_red_jsonata.erl

@@ -273,6 +273,58 @@ handle_local_function(
     [Str, Start, Len]
 ) when is_binary(Str), is_integer(Start), is_integer(Len) ->
     handle_local_function(jsonata_substring, [binary_to_list(Str), Start, Len]);
+%% ---> $match(...)
+handle_local_function(
+    jsonata_match,
+    [Str, RegExp]
+) ->
+    {ok, R} = re:compile(
+        any_to_list(RegExp),
+        [dotall, dollar_endonly, caseless]
+    ),
+    Args = [global],
+    case re:run(any_to_list(Str), R, [{capture, all, binary} | Args]) of
+        nomatch ->
+            undefined;
+        {match, CaptureBinary} ->
+            {match, CaptureIdx} =
+                re:run(any_to_list(Str), R, [{capture, all, index} | Args]),
+            match_capture_objects(CaptureBinary, CaptureIdx, [])
+    end;
+handle_local_function(
+    jsonata_match,
+    [Str, RegExp, MatchLimit]
+) when is_integer(MatchLimit) =:= false ->
+    handle_local_function(
+        jsonata_match,
+        [
+            Str,
+            RegExp,
+            list_to_integer(any_to_list(MatchLimit))
+        ]
+    );
+handle_local_function(
+    jsonata_match,
+    [_Str, _RegExp, MatchLimit] = Args
+) when is_integer(MatchLimit), MatchLimit < 0 ->
+    erlang:error(
+        "Invalid JSONata expression: Third argument of match function must evaluate to a positive number",
+        [{"$match", Args}]
+    );
+handle_local_function(
+    jsonata_match,
+    [_Str, _RegExp, MatchLimit]
+) when is_integer(MatchLimit), MatchLimit =:= 0 ->
+    undefined;
+handle_local_function(
+    jsonata_match,
+    [Str, RegExp, MatchLimit]
+) when is_integer(MatchLimit), MatchLimit > 0 ->
+    match_capture_limit(
+        handle_local_function(jsonata_match, [Str, RegExp]),
+        MatchLimit,
+        []
+    );
 %% -------> fall through to unsupported
 handle_local_function(FunctionName, Args) ->
     erlang:error(jsonata_unsupported, [{FunctionName, Args}]).
@@ -347,3 +399,33 @@ iso_8601_datestamp(Timestamp) ->
             [Year, Month, Day, Hour, Min, Sec]
         )
     ).
+
+%%
+%% See test id : #d206746f9f2594a6 for more format details
+%% --> https://flows.red-erik.org/f/d206746f9f2594a6
+%%
+match_capture_objects([], [], [Hd | []] = _Acc) ->
+    Hd;
+match_capture_objects([], [], Acc) ->
+    lists:reverse(Acc);
+match_capture_objects(
+    [[Matched | RestMatched] | RestBinary],
+    [[{MatchedIdx, _} | _RestMatched] | RestIndicies],
+    Acc
+) ->
+    CapHsh = #{
+        <<"match">> => Matched,
+        <<"index">> => MatchedIdx,
+        <<"groups">> => RestMatched
+    },
+    match_capture_objects(RestBinary, RestIndicies, [CapHsh | Acc]).
+%%
+%%
+match_capture_limit(undefined, _, _) ->
+    undefined;
+match_capture_limit(_Result, 0, [Hd | []] = _Acc) ->
+    Hd;
+match_capture_limit(_Result, 0, Acc) ->
+    lists:reverse(Acc);
+match_capture_limit([HD | Rest], MatchLimit, Acc) ->
+    match_capture_limit(Rest, MatchLimit - 1, [HD | Acc]).

src/erlang_red_jsonata_parser.erl

@@ -209,6 +209,8 @@ args_to_string([{string, _LineNo, String}|T], Acc) ->
     args_to_string(T, io_lib:format("~s, ~s", [Acc, String]));
 args_to_string([{name, _LineNo, String}|T], Acc) ->
     args_to_string(T, io_lib:format("~s, ~s", [Acc, String]));
+args_to_string([{regexp, _LineNo, String}|T], Acc) ->
+    args_to_string(T, io_lib:format("~s, ~s", [Acc, String]));
 args_to_string([H|T], Acc) ->
     args_to_string(T, io_lib:format("~s, ~s", [Acc, H])).
 
@@ -265,6 +267,9 @@ convert_funct({funct,_LineNo,FunctName}, Expr) ->
         substring ->
             list_to_binary(io_lib:format("jsonata_substring(~s)",
                                          [args_to_string(Expr)]));
+        match ->
+            list_to_binary(io_lib:format("jsonata_match(~s)",
+                                         [args_to_string(Expr)]));
         sum ->
             list_to_binary(io_lib:format("lists:sum(~s)",
                                          [args_to_string(Expr)]));
@@ -602,7 +607,7 @@ yecctoken2string1(Other) ->
 
 
 
--file("/code/src/erlang_red_jsonata_parser.erl", 605).
+-file("/code/src/erlang_red_jsonata_parser.erl", 610).
 
 -dialyzer({nowarn_function, yeccpars2/7}).
 -compile({nowarn_unused_function,  yeccpars2/7}).
@@ -4324,4 +4329,4 @@ yeccpars2_148_(__Stack0) ->
   end | __Stack].
 
 
--file("/code/src/erlang_red_jsonata_parser.yrl", 637).
+-file("/code/src/erlang_red_jsonata_parser.yrl", 642).

src/erlang_red_jsonata_parser.yrl

@@ -430,6 +430,8 @@ args_to_string([{string, _LineNo, String}|T], Acc) ->
     args_to_string(T, io_lib:format("~s, ~s", [Acc, String]));
 args_to_string([{name, _LineNo, String}|T], Acc) ->
     args_to_string(T, io_lib:format("~s, ~s", [Acc, String]));
+args_to_string([{regexp, _LineNo, String}|T], Acc) ->
+    args_to_string(T, io_lib:format("~s, ~s", [Acc, String]));
 args_to_string([H|T], Acc) ->
     args_to_string(T, io_lib:format("~s, ~s", [Acc, H])).
 
@@ -486,6 +488,9 @@ convert_funct({funct,_LineNo,FunctName}, Expr) ->
         substring ->
             list_to_binary(io_lib:format("jsonata_substring(~s)",
                                          [args_to_string(Expr)]));
+        match ->
+            list_to_binary(io_lib:format("jsonata_match(~s)",
+                                         [args_to_string(Expr)]));
         sum ->
             list_to_binary(io_lib:format("lists:sum(~s)",
                                          [args_to_string(Expr)]));