Support parsing of empty files

kolen · Feb 17, 2024 · 15daba0 · 15daba0
1 parent 73f2c13
commit 15daba0
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Showing 4 changed files with 33 additions and 5 deletions.
diff --git a/grammar.js b/grammar.js
@@ -46,7 +46,7 @@ module.exports = grammar({
   ],
 
   rules: {
-    source_file: $ => $._block,
+    source_file: $ => optional($._block),
 
     _block: $ => seq(
       $._block_start,

diff --git a/src/grammar.json b/src/grammar.json
@@ -2,8 +2,16 @@
   "name": "slim",
   "rules": {
     "source_file": {
-      "type": "SYMBOL",
-      "name": "_block"
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "_block"
+        },
+        {
+          "type": "BLANK"
+        }
+      ]
     },
     "_block": {
       "type": "SEQ",

diff --git a/src/scanner.cc b/src/scanner.cc
@@ -126,8 +126,13 @@ class Scanner {
       if (indents.empty()) {
         // Found initial indentation level
         indents.push_back(indent_length);
-        lexer->result_symbol = BLOCK_START;
-        return true;
+
+        if (valid_symbols[BLOCK_START] && !lexer->eof(lexer)) {
+          lexer->result_symbol = BLOCK_START;
+          return true;
+        } else {
+          return false;
+        }
       }
 
       int last_indent_length = (int)indents.back();

diff --git a/test/corpus/nesting.txt b/test/corpus/nesting.txt
@@ -52,3 +52,18 @@ p
     (nested
       (element
         (tag_name)))))
+
+==========
+Empty file
+==========
+---
+
+(source_file)
+
+==============================
+Empty file with one empty line
+==============================
+
+---
+
+(source_file)