maintenance/cssjanus/csslex.py

   1 #!/usr/bin/python
   2 #
   3 # Copyright 2007 Google Inc. All Rights Reserved.
   4
   5 """CSS Lexical Grammar rules.
   6
   7 CSS lexical grammar from http://www.w3.org/TR/CSS21/grammar.html
   8 """
   9
  10 __author__ = ['elsigh@google.com (Lindsey Simon)',
  11               'msamuel@google.com (Mike Samuel)']
  12
  13 # public symbols
  14 __all__ = [ "NEWLINE", "HEX", "NON_ASCII", "UNICODE", "ESCAPE", "NMSTART", "NMCHAR", "STRING1", "STRING2", "IDENT", "NAME", "HASH", "NUM", "STRING", "URL", "SPACE", "WHITESPACE", "COMMENT", "QUANTITY", "PUNC" ]
  15
  16 # The comments below are mostly copied verbatim from the grammar.
  17
  18 # "@import"               {return IMPORT_SYM;}
  19 # "@page"                 {return PAGE_SYM;}
  20 # "@media"                {return MEDIA_SYM;}
  21 # "@charset"              {return CHARSET_SYM;}
  22 KEYWORD = r'(?:\@(?:import|page|media|charset))'
  23
  24 # nl                      \n|\r\n|\r|\f ; a newline
  25 NEWLINE = r'\n|\r\n|\r|\f'
  26
  27 # h                       [0-9a-f]      ; a hexadecimal digit
  28 HEX = r'[0-9a-f]'
  29
  30 # nonascii                [\200-\377]
  31 NON_ASCII = r'[\200-\377]'
  32
  33 # unicode                 \\{h}{1,6}(\r\n|[ \t\r\n\f])?
  34 UNICODE = r'(?:(?:\\' + HEX + r'{1,6})(?:\r\n|[ \t\r\n\f])?)'
  35
  36 # escape                  {unicode}|\\[^\r\n\f0-9a-f]
  37 ESCAPE = r'(?:' + UNICODE + r'|\\[^\r\n\f0-9a-f])'
  38
  39 # nmstart                 [_a-z]|{nonascii}|{escape}
  40 NMSTART = r'(?:[_a-z]|' + NON_ASCII + r'|' + ESCAPE + r')'
  41
  42 # nmchar                  [_a-z0-9-]|{nonascii}|{escape}
  43 NMCHAR = r'(?:[_a-z0-9-]|' + NON_ASCII + r'|' + ESCAPE + r')'
  44
  45 # ident                   -?{nmstart}{nmchar}*
  46 IDENT = r'-?' + NMSTART + NMCHAR + '*'
  47
  48 # name                    {nmchar}+
  49 NAME = NMCHAR + r'+'
  50
  51 # hash
  52 HASH = r'#' + NAME
  53
  54 # string1                 \"([^\n\r\f\\"]|\\{nl}|{escape})*\"  ; "string"
  55 STRING1 = r'"(?:[^\"\\]|\\.)*"'
  56
  57 # string2                 \'([^\n\r\f\\']|\\{nl}|{escape})*\'  ; 'string'
  58 STRING2 = r"'(?:[^\'\\]|\\.)*'"
  59
  60 # string                  {string1}|{string2}
  61 STRING = '(?:' + STRING1 + r'|' + STRING2 + ')'
  62
  63 # num                     [0-9]+|[0-9]*"."[0-9]+
  64 NUM = r'(?:[0-9]*\.[0-9]+|[0-9]+)'
  65
  66 # s                       [ \t\r\n\f]
  67 SPACE = r'[ \t\r\n\f]'
  68
  69 # w                       {s}*
  70 WHITESPACE = '(?:' + SPACE + r'*)'
  71
  72 # url special chars
  73 URL_SPECIAL_CHARS = r'[!#$%&*-~]'
  74
  75 # url chars               ({url_special_chars}|{nonascii}|{escape})*
  76 URL_CHARS = r'(?:%s|%s|%s)*' % (URL_SPECIAL_CHARS, NON_ASCII, ESCAPE)
  77
  78 # url
  79 URL = r'url\(%s(%s|%s)%s\)' % (WHITESPACE, STRING, URL_CHARS, WHITESPACE)
  80
  81 # comments
  82 # see http://www.w3.org/TR/CSS21/grammar.html
  83 COMMENT = r'/\*[^*]*\*+([^/*][^*]*\*+)*/'
  84
  85 # {E}{M}             {return EMS;}
  86 # {E}{X}             {return EXS;}
  87 # {P}{X}             {return LENGTH;}
  88 # {C}{M}             {return LENGTH;}
  89 # {M}{M}             {return LENGTH;}
  90 # {I}{N}             {return LENGTH;}
  91 # {P}{T}             {return LENGTH;}
  92 # {P}{C}             {return LENGTH;}
  93 # {D}{E}{G}          {return ANGLE;}
  94 # {R}{A}{D}          {return ANGLE;}
  95 # {G}{R}{A}{D}       {return ANGLE;}
  96 # {M}{S}             {return TIME;}
  97 # {S}                {return TIME;}
  98 # {H}{Z}             {return FREQ;}
  99 # {K}{H}{Z}          {return FREQ;}
 100 # %                  {return PERCENTAGE;}
 101 UNIT = r'(?:em|ex|px|cm|mm|in|pt|pc|deg|rad|grad|ms|s|hz|khz|%)'
 102
 103 # {num}{UNIT|IDENT}                   {return NUMBER;}
 104 QUANTITY = '%s(?:%s%s|%s)?' % (NUM, WHITESPACE, UNIT, IDENT)
 105
 106 # "<!--"                  {return CDO;}
 107 # "-->"                   {return CDC;}
 108 # "~="                    {return INCLUDES;}
 109 # "|="                    {return DASHMATCH;}
 110 # {w}"{"                  {return LBRACE;}
 111 # {w}"+"                  {return PLUS;}
 112 # {w}">"                  {return GREATER;}
 113 # {w}","                  {return COMMA;}
 114 PUNC =  r'<!--|-->|~=|\|=|[\{\+>,:;]'