Create a top-level "third_party" directory

This directory now contains third_party software that is vendored into
the Servo source tree. The idea is that it would eventually hold
webrender and other crates from mozilla-central as well with a standard
patch management approach for each.

third_party/ply/example/yply/ylex.py

@@ -0,0 +1,119 @@
+# lexer for yacc-grammars
+#
+# Author: David Beazley (dave@dabeaz.com)
+# Date  : October 2, 2006
+
+import sys
+sys.path.append("../..")
+
+from ply import *
+
+tokens = (
+    'LITERAL', 'SECTION', 'TOKEN', 'LEFT', 'RIGHT', 'PREC', 'START', 'TYPE', 'NONASSOC', 'UNION', 'CODE',
+    'ID', 'QLITERAL', 'NUMBER',
+)
+
+states = (('code', 'exclusive'),)
+
+literals = [';', ',', '<', '>', '|', ':']
+t_ignore = ' \t'
+
+t_TOKEN = r'%token'
+t_LEFT = r'%left'
+t_RIGHT = r'%right'
+t_NONASSOC = r'%nonassoc'
+t_PREC = r'%prec'
+t_START = r'%start'
+t_TYPE = r'%type'
+t_UNION = r'%union'
+t_ID = r'[a-zA-Z_][a-zA-Z_0-9]*'
+t_QLITERAL  = r'''(?P<quote>['"]).*?(?P=quote)'''
+t_NUMBER = r'\d+'
+
+
+def t_SECTION(t):
+    r'%%'
+    if getattr(t.lexer, "lastsection", 0):
+        t.value = t.lexer.lexdata[t.lexpos + 2:]
+        t.lexer.lexpos = len(t.lexer.lexdata)
+    else:
+        t.lexer.lastsection = 0
+    return t
+
+# Comments
+
+
+def t_ccomment(t):
+    r'/\*(.|\n)*?\*/'
+    t.lexer.lineno += t.value.count('\n')
+
+t_ignore_cppcomment = r'//.*'
+
+
+def t_LITERAL(t):
+    r'%\{(.|\n)*?%\}'
+    t.lexer.lineno += t.value.count("\n")
+    return t
+
+
+def t_NEWLINE(t):
+    r'\n'
+    t.lexer.lineno += 1
+
+
+def t_code(t):
+    r'\{'
+    t.lexer.codestart = t.lexpos
+    t.lexer.level = 1
+    t.lexer.begin('code')
+
+
+def t_code_ignore_string(t):
+    r'\"([^\\\n]|(\\.))*?\"'
+
+
+def t_code_ignore_char(t):
+    r'\'([^\\\n]|(\\.))*?\''
+
+
+def t_code_ignore_comment(t):
+    r'/\*(.|\n)*?\*/'
+
+
+def t_code_ignore_cppcom(t):
+    r'//.*'
+
+
+def t_code_lbrace(t):
+    r'\{'
+    t.lexer.level += 1
+
+
+def t_code_rbrace(t):
+    r'\}'
+    t.lexer.level -= 1
+    if t.lexer.level == 0:
+        t.type = 'CODE'
+        t.value = t.lexer.lexdata[t.lexer.codestart:t.lexpos + 1]
+        t.lexer.begin('INITIAL')
+        t.lexer.lineno += t.value.count('\n')
+        return t
+
+t_code_ignore_nonspace = r'[^\s\}\'\"\{]+'
+t_code_ignore_whitespace = r'\s+'
+t_code_ignore = ""
+
+
+def t_code_error(t):
+    raise RuntimeError
+
+
+def t_error(t):
+    print("%d: Illegal character '%s'" % (t.lexer.lineno, t.value[0]))
+    print(t.value)
+    t.lexer.skip(1)
+
+lex.lex()
+
+if __name__ == '__main__':
+    lex.runmain()