1 files changed, 19 insertions, 13 deletions
diff --git a/pygments/lexers/math.py b/pygments/lexers/math.py
index a6d7a5c5..ead579e3 100644
--- a/pygments/lexers/math.py
+++ b/pygments/lexers/math.py
@@ -1010,34 +1010,40 @@ class SLexer(RegexLexer):
         ],
         'valid_name': [
             (r'[a-zA-Z][0-9a-zA-Z\._]+', Text),
-            (r'`.+`', String.Backtick),
+            # can begin with ., but not if that is followed by a digit
+            (r'\.[a-zA-Z_][0-9a-zA-Z\._]+', Text),
         ],
         'punctuation': [
-            (r'\[|\]|\[\[|\]\]|\$|\(|\)|@|:::?|;|,', Punctuation),
+            (r'\[{1,2}|\]{1,2}|\(|\)|;|,', Punctuation),
         ],
         'keywords': [
-            (r'for(?=\s*\()|while(?=\s*\()|if(?=\s*\()|(?<=\s)else|'
-             r'(?<=\s)break(?=;|$)|return(?=\s*\()|function(?=\s*\()',
+            (r'(if|else|for|while|repeat|in|next|break|return|switch|function)'
+             r'(?![0-9a-zA-Z\._])',
              Keyword.Reserved)
         ],
         'operators': [
-            (r'<-|-|==|<=|>=|<|>|&&|&|!=|\|\|?', Operator),
-            (r'\*|\+|\^|/|%%|%/%|=', Operator),
-            (r'%in%|%*%', Operator)
+            (r'<<?-|->>?|-|==|<=|>=|<|>|&&?|!=|\|\|?|\?', Operator),
+            (r'\*|\+|\^|/|!|%[^%]*%|=|~|\$|@|:{1,3}', Operator)
         ],
         'builtin_symbols': [
-            (r'(NULL|NA|TRUE|FALSE|NaN)\b', Keyword.Constant),
+            (r'(NULL|NA(_(integer|real|complex|character)_)?|'
+             r'Inf|TRUE|FALSE|NaN|\.\.(\.|[0-9]+))'
+             r'(?![0-9a-zA-Z\._])',
+             Keyword.Constant),
             (r'(T|F)\b', Keyword.Variable),
         ],
         'numbers': [
-            (r'(?<![0-9a-zA-Z\)\}\]`\"])(?=\s*)[-\+]?[0-9]+'
-             r'(\.[0-9]*)?(E[0-9][-\+]?(\.[0-9]*)?)?', Number),
-            (r'\.[0-9]*(E[0-9][-\+]?(\.[0-9]*)?)?', Number),
+            # hex number
+            (r'0[xX][a-fA-F0-9]+([pP][0-9]+)?[Li]?', Number.Hex),
+            # decimal number
+            (r'[+-]?([0-9]+(\.[0-9]+)?|\.[0-9]+)([eE][+-]?[0-9]+)?[Li]?',
+             Number),
         ],
         'statements': [
             include('comments'),
             # whitespaces
             (r'\s+', Text),
+            (r'`.*?`', String.Backtick),
             (r'\'', String, 'string_squote'),
             (r'\"', String, 'string_dquote'),
             include('builtin_symbols'),
@@ -1060,10 +1066,10 @@ class SLexer(RegexLexer):
         #    ('\}', Punctuation, '#pop')
         #],
         'string_squote': [
-            (r'[^\']*\'', String, '#pop'),
+            (r'([^\'\\]|\\.)*\'', String, '#pop'),
         ],
         'string_dquote': [
-            (r'[^\"]*\"', String, '#pop'),
+            (r'([^"\\]|\\.)*"', String, '#pop'),
         ],
     }