Add basic update_statement (#23)

examples/update.surql

@@ -0,0 +1,99 @@
+-- Create a Schemaless person table with a random id
+CREATE person CONTENT {
+    name: 'John',
+    company: 'Surrealist',
+    skills: ['JavaScript', 'Go' , 'SurrealQL']
+};
+
+-- Create another person with a specific id
+CREATE person:tobie CONTENT {
+    name: 'Tobie',
+    company: 'SurrealDB',
+    skills: ['JavaScript', 'Go' , 'SurrealQL']
+};
+
+-- Update all records in a table
+-- The `enjoys` field will also be an array.
+-- The += operator alone is enough to infer the type
+UPDATE person SET
+	dollars = 50,
+	skills += 'breathing',
+	enjoys += 'reading',
+	full_name = name + ' Mc' + name + 'erson';
+
+-- Update a record with a specific string id to add a new skill: 'Rust'
+UPDATE person:tobie SET skills += 'Rust';
+
+-- The -= operator can be used to remove an item from an array or reduce a numeric value by a certain value.
+
+UPDATE person:tobie SET
+	skills -= 'Go',
+	dollars -= 1;
+
+-- Remove the company field by setting it to NONE or using the UNSET keyword
+UPDATE person:tobie SET company = NONE;
+
+UPDATE person:tobie UNSET company;
+
+-- Update all records which match the condition that `company` is not equal to "SurrealDB"
+UPDATE person SET skills += "System design" WHERE company != "SurrealDB";
+
+-- Update all records with the same content
+UPDATE person CONTENT {
+	name: 'John',
+	company: 'SurrealDB',
+	skills: ['Rust', 'Go', 'JavaScript']
+};
+
+-- Oops, now they are both named John.
+-- Update a specific record with some content
+UPDATE person:tobie CONTENT {
+	name: 'Tobie',
+	company: 'SurrealDB',
+	skills: ['Rust', 'Go', 'JavaScript']
+};
+
+-- Update certain fields on all records
+UPDATE person MERGE {
+	settings: {
+		marketing: true
+	}
+};
+
+-- Update certain fields on a specific record
+UPDATE person:tobie MERGE {
+	settings: {
+		marketing: true
+	}
+};
+
+-- Patch the JSON response
+UPDATE person:tobie PATCH [
+	{
+		"op": "add",
+		"path": "Engineering",
+		"value": "true"
+	}
+]
+
+-- Don't return any result
+UPDATE person SET skills += 'reading' RETURN NONE;
+
+-- Return the changeset diff
+UPDATE person SET skills += 'reading' RETURN DIFF;
+
+-- Return the record before changes were applied
+UPDATE person SET skills += 'reading' RETURN BEFORE;
+
+-- Return the record after changes were applied (the default)
+UPDATE person SET skills += 'reading' RETURN AFTER;
+
+-- Return the value of the 'skills' field without the field name
+UPDATE person SET skills += 'reading' RETURN VALUE skills;
+
+-- Using a timeout
+UPDATE person
+	SET important = true
+	WHERE ->knows->person->(knows WHERE influencer = true)
+	TIMEOUT 5s;
+

grammar.js

@@ -174,8 +174,8 @@ module.exports = grammar({
     keyword_password_hash: _ => token("PASSHASH"),
     keyword_on_duplicate_key_update: _ => token("ON DUPLICATE KEY UPDATE"),
     keyword_count: _ => token("COUNT"),
-    keyword_set: _ => token("SET"),
     keyword_unset: _ => token("UNSET"),
+    keyword_set: _ => token("SET"),
 
     // Expressions
     expressions: $ =>
@@ -533,6 +533,7 @@ module.exports = grammar({
                 $.merge_clause,
                 $.patch_clause,
                 $.set_clause,
+                $.unset_clause,
               ),
             ),
             optional($.where_clause),
@@ -887,6 +888,8 @@ module.exports = grammar({
 
     set_clause: $ => seq($.keyword_set, commaSeparated($.field_assignment)),
 
+    unset_clause: $ => seq($.keyword_unset, commaSeparated($.identifier)),
+
     return_clause: $ =>
       seq(
         $.keyword_return,

queries/highlights.scm

@@ -152,6 +152,7 @@
   (keyword_return)
   (keyword_overwrite)
   (keyword_throw)
+  (keyword_unset)
 ] @keyword
 
 ; Operators