Add if_clause

so we can visit the first line of the `block_if_statement` in a single
node.

Author: inaki-amatria

grammar.js

@@ -1338,19 +1338,27 @@ module.exports = grammar({
     )),
 
     block_if_statement: $ => seq(
-      optional($.block_label_start_expression),
-      caseInsensitive('if'),
-      $._parenthesized_expression,
-      caseInsensitive('then'),
-      optional($._block_label),
-      $.end_of_statement,
+      $._if_clause,
       repeat($._statement),
       repeat($.elseif_clause),
       optional($.else_clause),
       optional($.statement_label),
       $.end_if_statement
     ),
 
+    _if_clause: $ => seq(
+      $.if_clause,
+      $.end_of_statement,
+    ),
+
+    if_clause: $ => seq(
+      optional($.block_label_start_expression),
+      caseInsensitive('if'),
+      $._parenthesized_expression,
+      caseInsensitive('then'),
+      optional($._block_label),
+    ),
+
     end_if_statement: $ => seq(
       whiteSpacedKeyword('end', 'if'),
       optional($._block_label)

src/grammar.json

@@ -14663,46 +14663,42 @@
     "block_if_statement": {
       "type": "SEQ",
       "members": [
+        {
+          "type": "SYMBOL",
+          "name": "_if_clause"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_statement"
+          }
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "elseif_clause"
+          }
+        },
         {
           "type": "CHOICE",
           "members": [
             {
               "type": "SYMBOL",
-              "name": "block_label_start_expression"
+              "name": "else_clause"
             },
             {
               "type": "BLANK"
             }
           ]
         },
-        {
-          "type": "ALIAS",
-          "content": {
-            "type": "PATTERN",
-            "value": "[iI][fF]"
-          },
-          "named": false,
-          "value": "if"
-        },
-        {
-          "type": "SYMBOL",
-          "name": "_parenthesized_expression"
-        },
-        {
-          "type": "ALIAS",
-          "content": {
-            "type": "PATTERN",
-            "value": "[tT][hH][eE][nN]"
-          },
-          "named": false,
-          "value": "then"
-        },
         {
           "type": "CHOICE",
           "members": [
             {
               "type": "SYMBOL",
-              "name": "_block_label"
+              "name": "statement_label"
             },
             {
               "type": "BLANK"
@@ -14711,49 +14707,71 @@
         },
         {
           "type": "SYMBOL",
-          "name": "end_of_statement"
-        },
+          "name": "end_if_statement"
+        }
+      ]
+    },
+    "_if_clause": {
+      "type": "SEQ",
+      "members": [
         {
-          "type": "REPEAT",
-          "content": {
-            "type": "SYMBOL",
-            "name": "_statement"
-          }
+          "type": "SYMBOL",
+          "name": "if_clause"
         },
         {
-          "type": "REPEAT",
-          "content": {
-            "type": "SYMBOL",
-            "name": "elseif_clause"
-          }
-        },
+          "type": "SYMBOL",
+          "name": "end_of_statement"
+        }
+      ]
+    },
+    "if_clause": {
+      "type": "SEQ",
+      "members": [
         {
           "type": "CHOICE",
           "members": [
             {
               "type": "SYMBOL",
-              "name": "else_clause"
+              "name": "block_label_start_expression"
             },
             {
               "type": "BLANK"
             }
           ]
         },
+        {
+          "type": "ALIAS",
+          "content": {
+            "type": "PATTERN",
+            "value": "[iI][fF]"
+          },
+          "named": false,
+          "value": "if"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_parenthesized_expression"
+        },
+        {
+          "type": "ALIAS",
+          "content": {
+            "type": "PATTERN",
+            "value": "[tT][hH][eE][nN]"
+          },
+          "named": false,
+          "value": "then"
+        },
         {
           "type": "CHOICE",
           "members": [
             {
               "type": "SYMBOL",
-              "name": "statement_label"
+              "name": "_block_label"
             },
             {
               "type": "BLANK"
             }
           ]
-        },
-        {
-          "type": "SYMBOL",
-          "name": "end_if_statement"
         }
       ]
     },