Merged array_tokens into recursive-parsing

This commit is contained in:
Tristan Hume
2013-07-29 10:38:52 -04:00
4 changed files with 40 additions and 72 deletions
+20 -45
View File
@@ -1,28 +1,5 @@
require "strscan"
module Liquid
class Token
attr_accessor :type, :contents
def initialize(type, contents = nil)
@type = type
@contents = contents
end
def inspect
out = "<#{@type}"
out << ": \'#{@contents}\'" if contents
out << '>'
end
def to_s
self.inspect
end
def ==(other)
return unless other && other.respond_to?(:type) && other.respond_to?(:contents)
@type == other.type && @contents == other.contents
end
end
class Lexer
SPECIALS = {
'|' => :pipe,
@@ -47,31 +24,33 @@ module Liquid
@output = []
loop do
tok = next_token
@ss.skip(/\s*/)
tok = case
when @ss.eos? then nil
when t = @ss.scan(COMPARISON_OPERATOR) then [:comparison, t]
when t = @ss.scan(SINGLE_STRING_LITERAL) then [:string, t]
when t = @ss.scan(DOUBLE_STRING_LITERAL) then [:string, t]
when t = @ss.scan(FLOAT_LITERAL) then [:float, t]
when t = @ss.scan(INTEGER_LITERAL) then [:integer, t]
when t = @ss.scan(IDENTIFIER) then [:id, t]
else
c = @ss.getch
if s = SPECIALS[c]
[s,c]
else
raise SyntaxError, "Unexpected character #{c}."
end
end
unless tok
@output << Token.new(:end_of_string)
@output << [:end_of_string]
return @output
end
@output << tok
end
end
def next_token
consume_whitespace
return if @ss.eos?
case
when t = @ss.scan(COMPARISON_OPERATOR) then Token.new(:comparison, t)
when t = @ss.scan(SINGLE_STRING_LITERAL) then Token.new(:string, t)
when t = @ss.scan(DOUBLE_STRING_LITERAL) then Token.new(:string, t)
when t = @ss.scan(FLOAT_LITERAL) then Token.new(:float, t)
when t = @ss.scan(INTEGER_LITERAL) then Token.new(:integer, t)
when t = @ss.scan(IDENTIFIER) then Token.new(:id, t)
else
lex_specials
end
end
protected
def lex_specials
c = @ss.getch
@@ -81,9 +60,5 @@ module Liquid
raise SyntaxError, "Unexpected character #{c}."
end
def consume_whitespace
@ss.skip(/\s*/)
end
end
end
+11 -11
View File
@@ -14,11 +14,11 @@ module Liquid
def consume(type = nil)
token = @tokens[@p]
if type && token.type != type
if type && token[0] != type
raise SyntaxError, "Expected #{type} but found #{@tokens[@p]}"
end
@p += 1
token.contents
token[1]
end
# Only consumes the token if it matches the type
@@ -26,35 +26,35 @@ module Liquid
# or false otherwise.
def consume?(type)
token = @tokens[@p]
return false unless token && token.type == type
return false unless token && token[0] == type
@p += 1
token.contents
token[1]
end
# Like consume? Except for an :id token of a certain name
def id?(str)
token = @tokens[@p]
return false unless token && token.type == :id
return false unless token.contents == str
return false unless token && token[0] == :id
return false unless token[1] == str
@p += 1
token.contents
token[1]
end
def look(type, ahead = 0)
tok = @tokens[@p + ahead]
return false unless tok
tok.type == type
tok[0] == type
end
# === General Liquid parsing functions ===
def expression
token = @tokens[@p]
if token.type == :id
if token[0] == :id
variable_signature
elsif [:string, :integer, :float].include? token.type
elsif [:string, :integer, :float].include? token[0]
consume
token.contents
token[1]
else
raise SyntaxError, "#{token} is not a valid expression."
end