From 1e4f8b9469bbfb58eb320b29a1a56cbb1055746d Mon Sep 17 00:00:00 2001
From: Amarin Phaosawasdi <amchiclet@users.noreply.github.com>
Date: Tue, 30 Jan 2024 05:56:31 -0800
Subject: [PATCH] elixir: support metavariable atoms

---
 .../src/semgrep-elixir/grammar.js                 | 15 ++++++++++++---
 .../src/semgrep-elixir/test/corpus/semgrep.txt    | 11 +++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/lang/semgrep-grammars/src/semgrep-elixir/grammar.js b/lang/semgrep-grammars/src/semgrep-elixir/grammar.js
index 3c1a9cc4..c5326353 100644
--- a/lang/semgrep-grammars/src/semgrep-elixir/grammar.js
+++ b/lang/semgrep-grammars/src/semgrep-elixir/grammar.js
@@ -29,14 +29,23 @@ module.exports = grammar(base_grammar, {
     },
 
     _keyword: ($, previous) => {
-	return choice(
-	    ...previous.members,
-	    $.metavariable_keyword
+      return choice(
+        ...previous.members,
+        $.metavariable_keyword
       );
     },
 
     metavariable_keyword: $ => seq($._semgrep_metavariable, /:\s/),
 
+    _atom: ($, previous) => {
+      return choice(
+        ...previous.members,
+        $.metavariable_atom
+      );
+    },
+
+    metavariable_atom: $ => seq(":", $._semgrep_metavariable),
+
     _semgrep_metavariable: $ => token(/\$[A-Z_][A-Z_0-9]*/),
 
     // Ellipsis
diff --git a/lang/semgrep-grammars/src/semgrep-elixir/test/corpus/semgrep.txt b/lang/semgrep-grammars/src/semgrep-elixir/test/corpus/semgrep.txt
index ef12d544..ef9c008f 100644
--- a/lang/semgrep-grammars/src/semgrep-elixir/test/corpus/semgrep.txt
+++ b/lang/semgrep-grammars/src/semgrep-elixir/test/corpus/semgrep.txt
@@ -29,6 +29,17 @@ Metavariables as key value pairs
           (metavariable_keyword)
           (identifier))))))
 
+=====================================
+Metavariables as atoms
+=====================================
+
+:$FOO
+
+---
+
+(source
+  (metavariable_atom))
+
 =====================================
 Ellipsis in calls
 =====================================