document the empty set literal

Author: divarvel

SPECIFICATIONS.md

@@ -121,9 +121,9 @@ We will represent the various types as follows:
 - date in RFC 3339 format: `1985-04-12T23:20:50.52Z`
 - boolean: `true` or `false`
 - null: `null`, supported since v3.3
-- set: `{ "a", "b", "c"}`
+- set: `{"a", "b", "c"}` (the empty set is `{,}`)
 - array: `[ "a", true, null]`, supported since v3.3
-- map: `{ "a": true, 12: "a" }`, supported since v3.3
+- map: `{ "a": true, 12: "a" }` (the empty map is `{}`), supported since v3.3
 
 As an example, assuming we have the following facts: `parent("a", "b")`,
 `parent("b", "c")`, `parent("c", "d")`. If we apply the rule
@@ -205,7 +205,7 @@ The logic language is described by the following EBNF grammar:
 <boolean> ::= "true" | "false"
 <null> ::= "null"
 <date> ::= [0-9]* "-" [0-9] [0-9] "-" [0-9] [0-9] "T" [0-9] [0-9] ":" [0-9] [0-9] ":" [0-9] [0-9] ( "Z" | ( ("+" | "-") [0-9] [0-9] ":" [0-9] [0-9] ))
-<set> ::= "{" <sp>? ( <set_term> ( <sp>? "," <sp>? <set_term>)* <sp>? )? "}"
+<set> ::= "{"  "," | (<sp>? ( <set_term> ( <sp>? "," <sp>? <set_term>)* <sp>? ) )"}"
 <array> ::= "[" <sp>? ( <term> ( <sp>? "," <sp>? <term>)* <sp>? )? "]"
 <map_entry> ::= (<string> | <number>) <sp>? ":" <sp>? <term>
 <map> ::= "{" <sp>? ( <map_entry> ( <sp>? "," <sp>? <map_entry>)* <sp>? )? "}"

samples/current/README.md

@@ -1321,6 +1321,7 @@ check if {1, 2}.intersection({2, 3}) === {2};
 check if {1, 2}.union({2, 3}) === {1, 2, 3};
 check if {1, 2, 3}.intersection({1, 2}).contains(1);
 check if {1, 2, 3}.intersection({1, 2}).length() === 2;
+check if {,}.length() === 0;
 ```
 
 ### validation
@@ -1331,7 +1332,7 @@ allow if true;
 ```
 
 revocation ids:
-- `d0420227266e3583a42dfaa0e38550d99f681d150dd18856f3af9a697bc9c5c8bf06b4b0fe5b9df0377d1b963574e2fd210a0a76a8b0756a65f640c602bebd07`
+- `fa358e4e3bea896415b1859e6cd347e64e1918fb86e31ae3fe208628321576a47f7a269760357e291c827ec9cbe322074f6860a546207a64e133c83a214bb505`
 
 authorizer world:
 ```
@@ -1372,6 +1373,7 @@ World {
             "check if true",
             "check if true === true",
             "check if {\"abc\", \"def\"}.contains(\"abc\")",
+            "check if {,}.length() === 0",
             "check if {1, 2, 3}.intersection({1, 2}).contains(1)",
             "check if {1, 2, 3}.intersection({1, 2}).length() === 2",
             "check if {1, 2} === {1, 2}",

samples/current/samples.json

@@ -1276,7 +1276,7 @@
           ],
           "public_keys": [],
           "external_key": null,
-          "code": "check if true;\ncheck if !false;\ncheck if true === true;\ncheck if false === false;\ncheck if 1 < 2;\ncheck if 2 > 1;\ncheck if 1 <= 2;\ncheck if 1 <= 1;\ncheck if 2 >= 1;\ncheck if 2 >= 2;\ncheck if 3 === 3;\ncheck if 1 + 2 * 3 - 4 / 2 === 5;\ncheck if \"hello world\".starts_with(\"hello\"), \"hello world\".ends_with(\"world\");\ncheck if \"aaabde\".matches(\"a*c?.e\");\ncheck if \"aaabde\".contains(\"abd\");\ncheck if \"aaabde\" === \"aaa\" + \"b\" + \"de\";\ncheck if \"abcD12\" === \"abcD12\";\ncheck if \"abcD12\".length() === 6;\ncheck if \"é\".length() === 2;\ncheck if 2019-12-04T09:46:41Z < 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z > 2019-12-04T09:46:41Z;\ncheck if 2019-12-04T09:46:41Z <= 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z >= 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z >= 2019-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z >= 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z === 2020-12-04T09:46:41Z;\ncheck if hex:12ab === hex:12ab;\ncheck if {1, 2}.contains(2);\ncheck if {2019-12-04T09:46:41Z, 2020-12-04T09:46:41Z}.contains(2020-12-04T09:46:41Z);\ncheck if {false, true}.contains(true);\ncheck if {\"abc\", \"def\"}.contains(\"abc\");\ncheck if {hex:12ab, hex:34de}.contains(hex:34de);\ncheck if {1, 2}.contains({2});\ncheck if {1, 2} === {1, 2};\ncheck if {1, 2}.intersection({2, 3}) === {2};\ncheck if {1, 2}.union({2, 3}) === {1, 2, 3};\ncheck if {1, 2, 3}.intersection({1, 2}).contains(1);\ncheck if {1, 2, 3}.intersection({1, 2}).length() === 2;\n",
+          "code": "check if true;\ncheck if !false;\ncheck if true === true;\ncheck if false === false;\ncheck if 1 < 2;\ncheck if 2 > 1;\ncheck if 1 <= 2;\ncheck if 1 <= 1;\ncheck if 2 >= 1;\ncheck if 2 >= 2;\ncheck if 3 === 3;\ncheck if 1 + 2 * 3 - 4 / 2 === 5;\ncheck if \"hello world\".starts_with(\"hello\"), \"hello world\".ends_with(\"world\");\ncheck if \"aaabde\".matches(\"a*c?.e\");\ncheck if \"aaabde\".contains(\"abd\");\ncheck if \"aaabde\" === \"aaa\" + \"b\" + \"de\";\ncheck if \"abcD12\" === \"abcD12\";\ncheck if \"abcD12\".length() === 6;\ncheck if \"é\".length() === 2;\ncheck if 2019-12-04T09:46:41Z < 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z > 2019-12-04T09:46:41Z;\ncheck if 2019-12-04T09:46:41Z <= 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z >= 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z >= 2019-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z >= 2020-12-04T09:46:41Z;\ncheck if 2020-12-04T09:46:41Z === 2020-12-04T09:46:41Z;\ncheck if hex:12ab === hex:12ab;\ncheck if {1, 2}.contains(2);\ncheck if {2019-12-04T09:46:41Z, 2020-12-04T09:46:41Z}.contains(2020-12-04T09:46:41Z);\ncheck if {false, true}.contains(true);\ncheck if {\"abc\", \"def\"}.contains(\"abc\");\ncheck if {hex:12ab, hex:34de}.contains(hex:34de);\ncheck if {1, 2}.contains({2});\ncheck if {1, 2} === {1, 2};\ncheck if {1, 2}.intersection({2, 3}) === {2};\ncheck if {1, 2}.union({2, 3}) === {1, 2, 3};\ncheck if {1, 2, 3}.intersection({1, 2}).contains(1);\ncheck if {1, 2, 3}.intersection({1, 2}).length() === 2;\ncheck if {,}.length() === 0;\n",
           "version": 3
         }
       ],
@@ -1317,6 +1317,7 @@
                   "check if true",
                   "check if true === true",
                   "check if {\"abc\", \"def\"}.contains(\"abc\")",
+                  "check if {,}.length() === 0",
                   "check if {1, 2, 3}.intersection({1, 2}).contains(1)",
                   "check if {1, 2, 3}.intersection({1, 2}).length() === 2",
                   "check if {1, 2} === {1, 2}",
@@ -1339,7 +1340,7 @@
           },
           "authorizer_code": "allow if true;\n",
           "revocation_ids": [
-            "d0420227266e3583a42dfaa0e38550d99f681d150dd18856f3af9a697bc9c5c8bf06b4b0fe5b9df0377d1b963574e2fd210a0a76a8b0756a65f640c602bebd07"
+            "fa358e4e3bea896415b1859e6cd347e64e1918fb86e31ae3fe208628321576a47f7a269760357e291c827ec9cbe322074f6860a546207a64e133c83a214bb505"
           ]
         }
       }