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|
# the scanner/lexer
require 'strscan'
require 'puppet'
module Puppet
class LexError < RuntimeError; end
end
module Puppet::Parser; end
class Puppet::Parser::Lexer
attr_reader :last, :file, :lexing_context, :token_queue
attr_accessor :line, :indefine
def lex_error msg
raise Puppet::LexError.new(msg)
end
class Token
attr_accessor :regex, :name, :string, :skip, :incr_line, :skip_text, :accumulate
def initialize(regex, name)
if regex.is_a?(String)
@name, @string = name, regex
@regex = Regexp.new(Regexp.escape(@string))
else
@name, @regex = name, regex
end
end
# MQR: Why not just alias?
%w{skip accumulate}.each do |method|
define_method(method+"?") do
self.send(method)
end
end
def to_s
if self.string
@string
else
@name.to_s
end
end
def acceptable?(context={})
# By default tokens are aceeptable in any context
true
end
end
# Maintain a list of tokens.
class TokenList
attr_reader :regex_tokens, :string_tokens
def [](name)
@tokens[name]
end
# Create a new token.
def add_token(name, regex, options = {}, &block)
token = Token.new(regex, name)
raise(ArgumentError, "Token #{name} already exists") if @tokens.include?(name)
@tokens[token.name] = token
if token.string
@string_tokens << token
@tokens_by_string[token.string] = token
else
@regex_tokens << token
end
options.each do |name, option|
token.send(name.to_s + "=", option)
end
token.meta_def(:convert, &block) if block_given?
token
end
def initialize
@tokens = {}
@regex_tokens = []
@string_tokens = []
@tokens_by_string = {}
end
# Look up a token by its value, rather than name.
def lookup(string)
@tokens_by_string[string]
end
# Define more tokens.
def add_tokens(hash)
hash.each do |regex, name|
add_token(name, regex)
end
end
# Sort our tokens by length, so we know once we match, we're done.
# This helps us avoid the O(n^2) nature of token matching.
def sort_tokens
@string_tokens.sort! { |a, b| b.string.length <=> a.string.length }
end
end
TOKENS = TokenList.new
TOKENS.add_tokens(
'[' => :LBRACK,
']' => :RBRACK,
'{' => :LBRACE,
'}' => :RBRACE,
'(' => :LPAREN,
')' => :RPAREN,
'=' => :EQUALS,
'+=' => :APPENDS,
'==' => :ISEQUAL,
'>=' => :GREATEREQUAL,
'>' => :GREATERTHAN,
'<' => :LESSTHAN,
'<=' => :LESSEQUAL,
'!=' => :NOTEQUAL,
'!' => :NOT,
',' => :COMMA,
'.' => :DOT,
':' => :COLON,
'@' => :AT,
'<<|' => :LLCOLLECT,
'->' => :IN_EDGE,
'<-' => :OUT_EDGE,
'~>' => :IN_EDGE_SUB,
'<~' => :OUT_EDGE_SUB,
'|>>' => :RRCOLLECT,
'<|' => :LCOLLECT,
'|>' => :RCOLLECT,
';' => :SEMIC,
'?' => :QMARK,
'\\' => :BACKSLASH,
'=>' => :FARROW,
'+>' => :PARROW,
'+' => :PLUS,
'-' => :MINUS,
'/' => :DIV,
'*' => :TIMES,
'<<' => :LSHIFT,
'>>' => :RSHIFT,
'=~' => :MATCH,
'!~' => :NOMATCH,
%r{([a-z][-\w]*)?(::[a-z][-\w]*)+} => :CLASSNAME, # Require '::' in the class name, else we'd compete with NAME
%r{((::){0,1}[A-Z][-\w]*)+} => :CLASSREF,
"<string>" => :STRING,
"<dqstring up to first interpolation>" => :DQPRE,
"<dqstring between two interpolations>" => :DQMID,
"<dqstring after final interpolation>" => :DQPOST,
"<boolean>" => :BOOLEAN
)
TOKENS.add_token :NUMBER, %r{\b(?:0[xX][0-9A-Fa-f]+|0?\d+(?:\.\d+)?(?:[eE]-?\d+)?)\b} do |lexer, value|
[TOKENS[:NAME], value]
end
#:stopdoc: # Issue #4161
def (TOKENS[:NUMBER]).acceptable?(context={})
![:DQPRE,:DQMID].include? context[:after]
end
#:startdoc:
TOKENS.add_token :NAME, %r{[a-z0-9][-\w]*} do |lexer, value|
string_token = self
# we're looking for keywords here
if tmp = KEYWORDS.lookup(value)
string_token = tmp
if [:TRUE, :FALSE].include?(string_token.name)
value = eval(value)
string_token = TOKENS[:BOOLEAN]
end
end
[string_token, value]
end
[:NAME,:CLASSNAME,:CLASSREF].each { |name_token|
#:stopdoc: # Issue #4161
def (TOKENS[name_token]).acceptable?(context={})
![:DQPRE,:DQMID].include? context[:after]
end
#:startdoc:
}
TOKENS.add_token :COMMENT, %r{#.*}, :accumulate => true, :skip => true do |lexer,value|
value.sub!(/# ?/,'')
[self, value]
end
TOKENS.add_token :MLCOMMENT, %r{/\*(.*?)\*/}m, :accumulate => true, :skip => true do |lexer, value|
lexer.line += value.count("\n")
value.sub!(/^\/\* ?/,'')
value.sub!(/ ?\*\/$/,'')
[self,value]
end
TOKENS.add_token :REGEX, %r{/[^/\n]*/} do |lexer, value|
# Make sure we haven't matched an escaped /
while value[-2..-2] == '\\'
other = lexer.scan_until(%r{/})
value += other
end
regex = value.sub(%r{\A/}, "").sub(%r{/\Z}, '').gsub("\\/", "/")
[self, Regexp.new(regex)]
end
#:stopdoc: # Issue #4161
def (TOKENS[:REGEX]).acceptable?(context={})
[:NODE,:LBRACE,:RBRACE,:MATCH,:NOMATCH,:COMMA].include? context[:after]
end
#:startdoc:
TOKENS.add_token :RETURN, "\n", :skip => true, :incr_line => true, :skip_text => true
TOKENS.add_token :SQUOTE, "'" do |lexer, value|
[TOKENS[:STRING], lexer.slurpstring(value).first ]
end
DQ_initial_token_types = {'$' => :DQPRE,'"' => :STRING}
DQ_continuation_token_types = {'$' => :DQMID,'"' => :DQPOST}
TOKENS.add_token :DQUOTE, /"/ do |lexer, value|
lexer.tokenize_interpolated_string(DQ_initial_token_types)
end
TOKENS.add_token :DQCONT, /\}/ do |lexer, value|
lexer.tokenize_interpolated_string(DQ_continuation_token_types)
end
#:stopdoc: # Issue #4161
def (TOKENS[:DQCONT]).acceptable?(context={})
context[:string_interpolation_depth] > 0
end
#:startdoc:
TOKENS.add_token :DOLLAR_VAR, %r{\$(\w*::)*\w+} do |lexer, value|
[TOKENS[:VARIABLE],value[1..-1]]
end
TOKENS.add_token :VARIABLE, %r{(\w*::)*\w+}
#:stopdoc: # Issue #4161
def (TOKENS[:VARIABLE]).acceptable?(context={})
[:DQPRE,:DQMID].include? context[:after]
end
#:startdoc:
TOKENS.sort_tokens
@@pairs = {
"{" => "}",
"(" => ")",
"[" => "]",
"<|" => "|>",
"<<|" => "|>>"
}
KEYWORDS = TokenList.new
KEYWORDS.add_tokens(
"case" => :CASE,
"class" => :CLASS,
"default" => :DEFAULT,
"define" => :DEFINE,
"import" => :IMPORT,
"if" => :IF,
"elsif" => :ELSIF,
"else" => :ELSE,
"inherits" => :INHERITS,
"node" => :NODE,
"and" => :AND,
"or" => :OR,
"undef" => :UNDEF,
"false" => :FALSE,
"true" => :TRUE,
"in" => :IN
)
def clear
initvars
end
def expected
return nil if @expected.empty?
name = @expected[-1]
TOKENS.lookup(name) or lex_error "Could not find expected token #{name}"
end
# scan the whole file
# basically just used for testing
def fullscan
array = []
self.scan { |token, str|
# Ignore any definition nesting problems
@indefine = false
array.push([token,str])
}
array
end
def file=(file)
@file = file
@line = 1
@scanner = StringScanner.new(File.read(file))
end
def shift_token
@token_queue.shift
end
def find_string_token
# We know our longest string token is three chars, so try each size in turn
# until we either match or run out of chars. This way our worst-case is three
# tries, where it is otherwise the number of string token we have. Also,
# the lookups are optimized hash lookups, instead of regex scans.
#
s = @scanner.peek(3)
token = TOKENS.lookup(s[0,3]) || TOKENS.lookup(s[0,2]) || TOKENS.lookup(s[0,1])
[ token, token && @scanner.scan(token.regex) ]
end
# Find the next token that matches a regex. We look for these first.
def find_regex_token
@regex += 1
best_token = nil
best_length = 0
# I tried optimizing based on the first char, but it had
# a slightly negative affect and was a good bit more complicated.
TOKENS.regex_tokens.each do |token|
if length = @scanner.match?(token.regex) and token.acceptable?(lexing_context)
# We've found a longer match
if length > best_length
best_length = length
best_token = token
end
end
end
return best_token, @scanner.scan(best_token.regex) if best_token
end
# Find the next token, returning the string and the token.
def find_token
@find += 1
shift_token || find_regex_token || find_string_token
end
def indefine?
if defined?(@indefine)
@indefine
else
false
end
end
def initialize
@find = 0
@regex = 0
initvars
end
def initvars
@line = 1
@previous_token = nil
@scanner = nil
@file = nil
# AAARRGGGG! okay, regexes in ruby are bloody annoying
# no one else has "\n" =~ /\s/
@skip = %r{[ \t\r]+}
@namestack = []
@token_queue = []
@indefine = false
@expected = []
@commentstack = [ ['', @line] ]
@lexing_context = {
:after => nil,
:start_of_line => true,
:string_interpolation_depth => 0
}
end
# Make any necessary changes to the token and/or value.
def munge_token(token, value)
@line += 1 if token.incr_line
skip if token.skip_text
return if token.skip and not token.accumulate?
token, value = token.convert(self, value) if token.respond_to?(:convert)
return unless token
if token.accumulate?
comment = @commentstack.pop
comment[0] << value + "\n"
@commentstack.push(comment)
end
return if token.skip
return token, { :value => value, :line => @line }
end
# Go up one in the namespace.
def namepop
@namestack.pop
end
# Collect the current namespace.
def namespace
@namestack.join("::")
end
# This value might have :: in it, but we don't care -- it'll be
# handled normally when joining, and when popping we want to pop
# this full value, however long the namespace is.
def namestack(value)
@namestack << value
end
def rest
@scanner.rest
end
# this is the heart of the lexer
def scan
#Puppet.debug("entering scan")
lex_error "Invalid or empty string" unless @scanner
# Skip any initial whitespace.
skip
until token_queue.empty? and @scanner.eos? do
yielded = false
matched_token, value = find_token
# error out if we didn't match anything at all
lex_error "Could not match #{@scanner.rest[/^(\S+|\s+|.*)/]}" unless matched_token
newline = matched_token.name == :RETURN
# this matches a blank line; eat the previously accumulated comments
getcomment if lexing_context[:start_of_line] and newline
lexing_context[:start_of_line] = newline
final_token, token_value = munge_token(matched_token, value)
unless final_token
skip
next
end
lexing_context[:after] = final_token.name unless newline
lexing_context[:string_interpolation_depth] += 1 if final_token.name == :DQPRE
lexing_context[:string_interpolation_depth] -= 1 if final_token.name == :DQPOST
value = token_value[:value]
if match = @@pairs[value] and final_token.name != :DQUOTE and final_token.name != :SQUOTE
@expected << match
elsif exp = @expected[-1] and exp == value and final_token.name != :DQUOTE and final_token.name != :SQUOTE
@expected.pop
end
if final_token.name == :LBRACE
commentpush
end
yield [final_token.name, token_value]
if @previous_token
namestack(value) if @previous_token.name == :CLASS
if @previous_token.name == :DEFINE
if indefine?
msg = "Cannot nest definition #{value} inside #{@indefine}"
self.indefine = false
raise Puppet::ParseError, msg
end
@indefine = value
end
end
@previous_token = final_token
skip
end
@scanner = nil
# This indicates that we're done parsing.
yield [false,false]
end
# Skip any skipchars in our remaining string.
def skip
@scanner.skip(@skip)
end
# Provide some limited access to the scanner, for those
# tokens that need it.
def scan_until(regex)
@scanner.scan_until(regex)
end
# we've encountered the start of a string...
# slurp in the rest of the string and return it
Valid_escapes_in_strings = %w{ \\ $ ' " n t s }+["\n"]
def slurpstring(terminators)
# we search for the next quote that isn't preceded by a
# backslash; the caret is there to match empty strings
str = @scanner.scan_until(/([^\\]|^)[#{terminators}]/) or lex_error "Unclosed quote after '#{last}' in '#{rest}'"
@line += str.count("\n") # literal carriage returns add to the line count.
str.gsub!(/\\(.)/) {
case ch=$1
when 'n'; "\n"
when 't'; "\t"
when 's'; " "
else
if Valid_escapes_in_strings.include? ch and not (ch == '"' and terminators == "'")
ch
else
Puppet.warning "Unrecognised escape sequence '\\#{ch}'#{file && " in file #{file}"}#{line && " at line #{line}"}"
"\\#{ch}"
end
end
}
[ str[0..-2],str[-1,1] ]
end
def tokenize_interpolated_string(token_type)
value,terminator = slurpstring('"$')
token_queue << [TOKENS[token_type[terminator]],value]
while terminator == '$' and not @scanner.scan(/\{/)
token_queue << [TOKENS[:VARIABLE],@scanner.scan(%r{(\w*::)*\w+|[0-9]})]
value,terminator = slurpstring('"$')
token_queue << [TOKENS[DQ_continuation_token_types[terminator]],value]
end
token_queue.shift
end
# just parse a string, not a whole file
def string=(string)
@scanner = StringScanner.new(string)
end
# returns the content of the currently accumulated content cache
def commentpop
@commentstack.pop[0]
end
def getcomment(line = nil)
comment = @commentstack.last
if line.nil? or comment[1] <= line
@commentstack.pop
@commentstack.push(['', @line])
return comment[0]
end
''
end
def commentpush
@commentstack.push(['', @line])
end
end
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