diff --git a/grammar.js b/grammar.js
index 4db095e..bf04d47 100644
--- a/grammar.js
+++ b/grammar.js
@@ -2,6 +2,24 @@ module.exports = grammar({
   name: 'CMake',
 
   rules: {
-    source_file: $ => 'hello'
+    source_file: $ => repeat($.command_invocation),
+
+    line_ending: $ => $.newline,
+    space: $ => /[ \t]+/,
+    newline: $ => /\n/,
+    identifier: $ => /[A-Za-z_][A-Za-z0-9_]*/,
+    argument: $ => /[^ ()#\"\\]+/,
+
+    command_invocation: $ => seq(
+      repeat($.space),
+      $.identifier,
+      repeat($.space),
+      $.parameter_list,
+    ),
+    parameter_list: $ => seq(
+      '(',
+      repeat($.argument),
+      ')'
+    )
   }
 })