Use __slots__ for fast attribute access during parsing

lib/spack/spack/parse.py

@@ -17,6 +17,8 @@
 class Token(object):
     """Represents tokens; generated from input by lexer and fed to parse()."""
 
+    __slots__ = 'type', 'value', 'start', 'end'
+
     def __init__(self, type, value="", start=0, end=0):
         self.type = type
         self.value = value
@@ -39,6 +41,8 @@ def __eq__(self, other):
 class Lexer(object):
     """Base class for Lexers that keep track of line numbers."""
 
+    __slots__ = 'scanner0', 'scanner1', 'mode', 'mode_switches_01', 'mode_switches_10'
+
     def __init__(self, lexicon0, mode_switches_01=[], lexicon1=[], mode_switches_10=[]):
         self.scanner0 = re.Scanner(lexicon0)
         self.mode_switches_01 = mode_switches_01
@@ -89,6 +93,8 @@ def lex(self, text):
 class Parser(object):
     """Base class for simple recursive descent parsers."""
 
+    __slots__ = 'tokens', 'token', 'next', 'lexer', 'text'
+
     def __init__(self, lexer):
         self.tokens = iter([])  # iterators over tokens, handled in order.
         self.token = Token(None)  # last accepted token

lib/spack/spack/spec.py

@@ -4983,6 +4983,8 @@ def __init__(self):
 class SpecParser(spack.parse.Parser):
     """Parses specs."""
 
+    __slots__ = 'previous', '_initial'
+
     def __init__(self, initial_spec=None):
         """Construct a new SpecParser.