Add basic if-statement

examples/if_else.surql

@@ -0,0 +1,77 @@
+-- The smallest possible IF THEN statement simply does something when a condition is true, and nothing otherwise.
+IF 9 = 9 { RETURN 'Nine is indeed nine' };
+
+-- As the last line of a scope is its return value, the RETURN keyword can also be placed before the entire IF THEN
+-- statement. This is particularly convenient in long IF ELSE chains to avoid using the RETURN keyword at the end
+-- of every check for a condition.
+
+LET $num = 100;
+
+RETURN IF $num < 0 {
+    "Negative"
+} ELSE IF $num = 0 {
+    "Zero"
+} ELSE IF $num = 13 {
+    "Thirteen"
+} ELSE {
+    "Positive uninteresting number"
+};
+
+-- The THROW keyword inside {} braces can be used to break out of an IF LET statement early.
+LET $badly_formatted_datetime = "2024-04TT08:08:08Z";
+
+IF !type::is::datetime($badly_formatted_datetime) {
+    THROW "Whoops, that isn't a real datetime"
+};
+
+-- ELSE IF branches and a final ELSE can be added into an IF ELSE statement:
+RETURN
+    IF $access = "admin" { (SELECT * FROM account) }
+    ELSE IF $access = "user"  { (SELECT * FROM $auth.account) }
+    ELSE { THROW "Access method hasn't been defined!" };
+
+-- The output of an IF ELSE statement can be assigned to a parameter:
+LET $num = 9;
+LET $odd_even =
+    IF $num % 2 = 0 { "even" } 
+    ELSE { "odd" };
+
+-- If-else statements can also be used as subqueries within other statements.
+UPDATE person SET railcard =
+    IF age <= 10 { 'junior' }
+    ELSE IF age <= 21 { 'student' }
+    ELSE IF age >= 65 { 'senior' }
+    ELSE { NULL };
+
+-- More nested
+IF $access = 'admin'
+{
+    CREATE admin_user_event SET 
+        time = time::now(),
+             info = "Admin user activity registered";
+    SELECT * FROM admin_data WHERE access_level = 'full';
+}
+ELSE IF $access = 'user'
+{
+    IF $auth.role = 'premium'
+    {
+        CREATE premium_user_event SET 
+            time = time::now(),
+                 info = "Premium user activity registered";
+
+        IF $auth.subscription_status = 'active'
+            { SELECT * FROM premium_user_data WHERE active = 1 }
+        ELSE IF $auth.subscription_status = 'trial'
+            { SELECT * FROM trial_user_data }
+        ELSE
+            { SELECT * FROM basic_user_data }
+    }
+    ELSE IF $auth.role = 'standard'
+        { SELECT * FROM standard_user_data WHERE region = 'US' }
+    ELSE IF $auth.role = 'standard' AND $auth.subscription_status = 'active'
+        { SELECT * FROM standard_user_data WHERE region = 'EU' }
+    ELSE
+        { SELECT * FROM unauthorized_user_data }
+}
+ELSE
+    { SELECT * FROM unknown_access_data }

grammar.js

@@ -21,14 +21,14 @@ module.exports = grammar({
     semi_colon: _ => token(";"),
     keyword_info: _ => token("INFO"),
     keyword_if: _ => token("IF"),
+    keyword_throw: _ => token("THROW"),
     keyword_exists: _ => token("EXISTS"),
     keyword_tokenizers: _ => token("TOKENIZERS"),
     keyword_overwrite: _ => token("OVERWRITE"),
     keyword_on: _ => token("ON"),
     keyword_let: _ => token("LET"),
     keyword_return: _ => token("RETURN"),
     keyword_else: _ => token("ELSE"),
-    keyword_end: _ => token("END"),
     keyword_select: _ => token("SELECT"),
     keyword_from: _ => token("FROM"),
     keyword_only: _ => token("ONLY"),
@@ -40,7 +40,6 @@ module.exports = grammar({
     keyword_parallel: _ => token("PARALLEL"),
     keyword_timeout: _ => token("TIMEOUT"),
     keyword_fetch: _ => token("FETCH"),
-    keyword_start_at: _ => token("START AT"),
     keyword_limit: _ => token("LIMIT"),
     keyword_by: _ => token("BY"),
     keyword_rand: _ => token("RAND"),
@@ -56,7 +55,6 @@ module.exports = grammar({
     keyword_split: _ => token("SPLIT"),
     keyword_at: _ => token("AT"),
     keyword_group: _ => token("GROUP"),
-    keyword_all: _ => token("ALL"),
     keyword_true: _ => token("TRUE"),
     keyword_false: _ => token("FALSE"),
     keyword_begin: _ => token("BEGIN"),
@@ -178,10 +176,6 @@ module.exports = grammar({
     keyword_count: _ => token("COUNT"),
     keyword_set: _ => token("SET"),
     keyword_unset: _ => token("UNSET"),
-    keyword_return: _ => token("RETURN"),
-    keyword_dimension: _ => token("DIMENSION"),
-    keyword_mtree: _ => token("MTREE"),
-    keyword_dist: _ => token("DIST"),
 
     // Expressions
     expressions: $ =>
@@ -222,9 +216,39 @@ module.exports = grammar({
         $.use_statement,
         $.info_statement,
         $.let_statement,
+        $.if_statement,
+        $.throw_statement,
+        $.return_statement,
       ),
 
-    let_statement: $ => seq($.keyword_let, $.variable_name, "=", $.value),
+    return_statement: $ => $.return_clause,
+
+    throw_statement: $ => seq(
+      $.keyword_throw,
+      $.value
+    ),
+
+    if_statement: $ => seq(
+      $.keyword_if,
+      $.value,
+      $.block,
+      repeat($.else_if_clause),
+      optional($.else_clause),
+    ),
+
+    else_if_clause: $ => seq(
+      $.keyword_else,
+      $.keyword_if,
+      $.value,
+      $.block
+    ),
+
+    else_clause: $ => seq(
+      $.keyword_else,
+      $.block
+    ),
+
+    let_statement: $ => seq($.keyword_let, $.variable_name, "=", choice($.value, $.if_statement)),
 
     info_statement: $ => seq($.keyword_info, $.keyword_for, $.info_target),
 
@@ -672,7 +696,6 @@ module.exports = grammar({
       ),
 
     limit_clause: $ => seq($.keyword_limit, $.number),
-    start_clause: $ => seq($.keyword_start_at, $.number),
     fetch_clause: $ => seq($.keyword_fetch, commaSeparated($.identifier)),
     timeout_clause: $ => seq($.keyword_timeout, $.duration),
     parallel_clause: $ => $.keyword_parallel,
@@ -876,6 +899,7 @@ module.exports = grammar({
           $.keyword_after,
           $.keyword_diff,
           commaSeparated($.value),
+          $.if_statement
         ),
       ),
 
@@ -896,13 +920,13 @@ module.exports = grammar({
 
     // Value-related rules
     value: $ =>
-      choice($.base_value, $.binary_expression, $.path, $.function_call),
+      choice($.base_value, $.binary_expression, $.path, $.function_call, $.negated_expression),
 
     function_call: $ =>
       choice(
         seq($.keyword_count, $.argument_list_count),
         seq(
-          choice($.function_name, $.custom_function_name, $.keyword_rand),
+          choice($.function_name, $.custom_function_name, $.keyword_rand, seq($.identifier, repeat1(seq('::', $.identifier)))),
           optional($.version),
           $.argument_list,
         ),
@@ -929,6 +953,11 @@ module.exports = grammar({
 
     binary_expression: $ => prec.left(seq($.value, $.operator, $.value)),
 
+    negated_expression: $ => seq(
+      '!',
+      $.function_call,
+    ),
+
     path: $ =>
       choice(
         seq($.base_value, repeat1($.path_element)),
@@ -1035,6 +1064,7 @@ module.exports = grammar({
         "=",
         ">",
         "<",
+        "%",
         $.keyword_and,
         $.keyword_or,
         $.keyword_is,

package.json

@@ -49,16 +49,6 @@
       "optional": true
     }
   },
-  "tree-sitter": [
-    {
-      "file-types": [
-        "surql"
-      ],
-      "highlights": [
-        "queries/highlights.scm"
-      ]
-    }
-  ],
   "devDependencies": {
     "prettier": "3.1.0",
     "tree-sitter-cli": "^0.22.5",

queries/highlights.scm

@@ -4,7 +4,6 @@
   (keyword_from)
   (keyword_let)
   (keyword_else)
-  (keyword_end)
   (keyword_only)
   (keyword_value)
   (keyword_as)
@@ -14,7 +13,6 @@
   (keyword_parallel)
   (keyword_timeout)
   (keyword_fetch)
-  (keyword_start_at)
   (keyword_limit)
   (keyword_by)
   (keyword_rand)
@@ -30,7 +28,6 @@
   (keyword_split)
   (keyword_at)
   (keyword_group)
-  (keyword_all)
   (keyword_begin)
   (keyword_cancel)
   (keyword_commit)
@@ -154,10 +151,8 @@
   (keyword_set)
   (keyword_unset)
   (keyword_return)
-  (keyword_dimension)
-  (keyword_mtree)
-  (keyword_dist)
   (keyword_overwrite)
+  (keyword_throw)
 ] @keyword
 
 ; Operators
@@ -222,3 +217,4 @@
 (graph_path) @operator
 
 ; Errors
+(ERROR) @error