grammar: add unique column constraint

grammar.js

@@ -55,7 +55,13 @@ module.exports = grammar({
         choice(
           $._not_null,
           $.keyword_null,
-          seq($.keyword_default, $._expression)
+          seq($.keyword_default, $._expression),
+          seq(
+            $.keyword_unique,
+            optional(
+              seq($.keyword_nulls, optional($.keyword_not), $.keyword_distinct)
+            )
+          )
           // TODO: CHECK
           // TODO: GENERATED
           // TODO: UNIQUE
@@ -102,6 +108,9 @@ module.exports = grammar({
     keyword_default: (_) => mkKeyword("default"),
     keyword_true: (_) => mkKeyword("true"),
     keyword_false: (_) => mkKeyword("false"),
+    keyword_nulls: (_) => mkKeyword("nulls"),
+    keyword_distinct: (_) => mkKeyword("distinct"),
+    keyword_unique: (_) => mkKeyword("unique"),
 
     // References: https://www.postgresql.org/docs/15/datatype.html
     _type: ($) =>

src/grammar.json

@@ -242,6 +242,48 @@
                   "name": "_expression"
                 }
               ]
+            },
+            {
+              "type": "SEQ",
+              "members": [
+                {
+                  "type": "SYMBOL",
+                  "name": "keyword_unique"
+                },
+                {
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "SEQ",
+                      "members": [
+                        {
+                          "type": "SYMBOL",
+                          "name": "keyword_nulls"
+                        },
+                        {
+                          "type": "CHOICE",
+                          "members": [
+                            {
+                              "type": "SYMBOL",
+                              "name": "keyword_not"
+                            },
+                            {
+                              "type": "BLANK"
+                            }
+                          ]
+                        },
+                        {
+                          "type": "SYMBOL",
+                          "name": "keyword_distinct"
+                        }
+                      ]
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
+                }
+              ]
             }
           ]
         }
@@ -406,6 +448,18 @@
       "type": "PATTERN",
       "value": "false|FALSE"
     },
+    "keyword_nulls": {
+      "type": "PATTERN",
+      "value": "nulls|NULLS"
+    },
+    "keyword_distinct": {
+      "type": "PATTERN",
+      "value": "distinct|DISTINCT"
+    },
+    "keyword_unique": {
+      "type": "PATTERN",
+      "value": "unique|UNIQUE"
+    },
     "_type": {
       "type": "CHOICE",
       "members": [

src/node-types.json

@@ -57,6 +57,10 @@
           "type": "keyword_default",
           "named": true
         },
+        {
+          "type": "keyword_distinct",
+          "named": true
+        },
         {
           "type": "keyword_not",
           "named": true
@@ -65,6 +69,14 @@
           "type": "keyword_null",
           "named": true
         },
+        {
+          "type": "keyword_nulls",
+          "named": true
+        },
+        {
+          "type": "keyword_unique",
+          "named": true
+        },
         {
           "type": "literal",
           "named": true
@@ -560,6 +572,10 @@
     "type": "keyword_default",
     "named": true
   },
+  {
+    "type": "keyword_distinct",
+    "named": true
+  },
   {
     "type": "keyword_exists",
     "named": true
@@ -596,6 +612,10 @@
     "type": "keyword_null",
     "named": true
   },
+  {
+    "type": "keyword_nulls",
+    "named": true
+  },
   {
     "type": "keyword_numeric",
     "named": true
@@ -628,6 +648,10 @@
     "type": "keyword_true",
     "named": true
   },
+  {
+    "type": "keyword_unique",
+    "named": true
+  },
   {
     "type": "keyword_unlogged",
     "named": true

test/corpus/create/table.txt

@@ -174,7 +174,7 @@ Create a table with column constraints
 create table foo (
   c1  text  not null,
   c2  text  null,
-  c2  text  not null default 'hello'
+  c3  text  not null default 'hello'
 );
 --------------------------------------------------------------------------------
 
@@ -225,7 +225,8 @@ Create a table with named column constraints
 create table foo (
   c1  text  constraint strong_c1 not null,
   c2  text  constraint weak_c2 null,
-  c3  text  constraint "c3 with power" not null constraint "c2 set default hello" default 'hello'
+  c3  text  constraint "c3 with power" not null constraint "c2 set default hello" default 'hello',
+  c4  text  constraint "c4 unique" unique nulls not distinct
 );
 --------------------------------------------------------------------------------
 
@@ -273,6 +274,18 @@ create table foo (
             (literal)
           )
         )
+        (column_definition
+          name: (identifier)
+          datatype: (keyword_text)
+          (column_constraint
+            (keyword_constraint)
+            name: (identifier)
+            (keyword_unique)
+            (keyword_nulls)
+            (keyword_not)
+            (keyword_distinct)
+          )
+        )
       )
     )
   )