diff --git a/SPEC.md b/SPEC.md
index 96cad16..e4d4d75 100644
--- a/SPEC.md
+++ b/SPEC.md
@@ -427,7 +427,10 @@ node-space := ws* escline ws* | ws+
 node-terminator := single-line-comment | newline | ';' | eof
 
 identifier := string | bare-identifier
-bare-identifier := ((identifier-char - digit - sign) identifier-char* | sign ((identifier-char - digit) identifier-char*)?) - keyword
+bare-identifier := (unambiguous-ident | numberish-ident | stringish-ident) - keyword
+unambiguous-ident := (identifier-char - digit - sign - "r") identifier-char*
+numberish-ident := sign ((identifier-char - digit) identifier-char*)?
+stringish-ident := "r" ((identifier-char - [#"]) identifier-char*)?
 identifier-char := unicode - linespace - [\/(){}<>;[]=,"]
 keyword := boolean | 'null'
 prop := identifier '=' value