Improved R syntax rules

runtime/syntax/r.yaml

@@ -4,9 +4,29 @@ detect:
     filename: "\\.(r|R)$"
 
 rules:
-    - statement: "\\b(break|else|for|function|if|in|next|repeat|return|while)\\b"
+
-    - constant: "\\b(TRUE|FALSE|NULL|Inf|NaN|NA|NA_integer_|NA_real_|NA_complex_|NA_character_)\\b"
+    - statement: "\\b(library|require|break|else|for|function|if|ifelse|in|next|names|switch|repeat|print|try|tryCatch|isTRUE|return|while)\\b"
+    - constant: "\\b(T|TRUE|F|FALSE|NULL|Inf|NaN|NA|NA_integer_|NA_real_|NA_complex_|NA_character_)\\b"
+    - constant.number: "(\\b[0-9]+\\b|\\b0x[0-9A-Fa-f]+\\b)"
+    - symbol.operator: "([.:;,+*|=!\\%]|<|>|/|-|&|\\^|\\$)" 
+
     - comment:
         start: "#"
         end: "$"
-        rules: []
+        rules:
+            - todo: "(TODO|XXX|FIXME):?"
+
+    - constant.string:
+        start: "\""
+        end: "\""
+        skip: "\\\\."
+        rules:
+            - constant.specialChar: "\\\\."
+
+    - constant.string:
+        start: "'"
+        end: "'"
+        skip: "\\\\."
+        rules:
+            - constant.specialChar: "\\\\."
+