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# frozen_string_literal: true
module Liquid
class Lexer
CLOSE_ROUND = [:close_round, ")"].freeze
CLOSE_SQUARE = [:close_square, "]"].freeze
COLON = [:colon, ":"].freeze
COMMA = [:comma, ","].freeze
COMPARISION_NOT_EQUAL = [:comparison, "!="].freeze
COMPARISON_CONTAINS = [:comparison, "contains"].freeze
COMPARISON_EQUAL = [:comparison, "=="].freeze
COMPARISON_GREATER_THAN = [:comparison, ">"].freeze
COMPARISON_GREATER_THAN_OR_EQUAL = [:comparison, ">="].freeze
COMPARISON_LESS_THAN = [:comparison, "<"].freeze
COMPARISON_LESS_THAN_OR_EQUAL = [:comparison, "<="].freeze
COMPARISON_NOT_EQUAL_ALT = [:comparison, "<>"].freeze
DASH = [:dash, "-"].freeze
DOT = [:dot, "."].freeze
DOTDOT = [:dotdot, ".."].freeze
DOT_ORD = ".".ord
DOUBLE_STRING_LITERAL = /"[^\"]*"/
EOS = [:end_of_string].freeze
IDENTIFIER = /[a-zA-Z_][\w-]*\??/
NUMBER_LITERAL = /-?\d+(\.\d+)?/
OPEN_ROUND = [:open_round, "("].freeze
OPEN_SQUARE = [:open_square, "["].freeze
PIPE = [:pipe, "|"].freeze
QUESTION = [:question, "?"].freeze
RUBY_WHITESPACE = [" ", "\t", "\r", "\n", "\f"].freeze
SINGLE_STRING_LITERAL = /'[^\']*'/
WHITESPACE_OR_NOTHING = /\s*/
SINGLE_COMPARISON_TOKENS = [].tap do |table|
table["<".ord] = COMPARISON_LESS_THAN
table[">".ord] = COMPARISON_GREATER_THAN
table.freeze
end
TWO_CHARS_COMPARISON_JUMP_TABLE = [].tap do |table|
table["=".ord] = [].tap do |sub_table|
sub_table["=".ord] = COMPARISON_EQUAL
sub_table.freeze
end
table["!".ord] = [].tap do |sub_table|
sub_table["=".ord] = COMPARISION_NOT_EQUAL
sub_table.freeze
end
table.freeze
end
COMPARISON_JUMP_TABLE = [].tap do |table|
table["<".ord] = [].tap do |sub_table|
sub_table["=".ord] = COMPARISON_LESS_THAN_OR_EQUAL
sub_table[">".ord] = COMPARISON_NOT_EQUAL_ALT
sub_table.freeze
end
table[">".ord] = [].tap do |sub_table|
sub_table["=".ord] = COMPARISON_GREATER_THAN_OR_EQUAL
sub_table.freeze
end
table.freeze
end
NEXT_MATCHER_JUMP_TABLE = [].tap do |table|
"a".upto("z") do |c|
table[c.ord] = [:id, IDENTIFIER].freeze
table[c.upcase.ord] = [:id, IDENTIFIER].freeze
end
table["_".ord] = [:id, IDENTIFIER].freeze
"0".upto("9") do |c|
table[c.ord] = [:number, NUMBER_LITERAL].freeze
end
table["-".ord] = [:number, NUMBER_LITERAL].freeze
table["'".ord] = [:string, SINGLE_STRING_LITERAL].freeze
table["\"".ord] = [:string, DOUBLE_STRING_LITERAL].freeze
table.freeze
end
SPECIAL_TABLE = [].tap do |table|
table["|".ord] = PIPE
table[".".ord] = DOT
table[":".ord] = COLON
table[",".ord] = COMMA
table["[".ord] = OPEN_SQUARE
table["]".ord] = CLOSE_SQUARE
table["(".ord] = OPEN_ROUND
table[")".ord] = CLOSE_ROUND
table["?".ord] = QUESTION
table["-".ord] = DASH
end
NUMBER_TABLE = [].tap do |table|
"0".upto("9") do |c|
table[c.ord] = true
end
table.freeze
end
# rubocop:disable Metrics/BlockNesting
class << self
def tokenize(ss)
output = []
until ss.eos?
ss.skip(WHITESPACE_OR_NOTHING)
break if ss.eos?
start_pos = ss.pos
peeked = ss.peek_byte
if (special = SPECIAL_TABLE[peeked])
ss.scan_byte
# Special case for ".."
if special == DOT && ss.peek_byte == DOT_ORD
ss.scan_byte
output << DOTDOT
elsif special == DASH
# Special case for negative numbers
if (peeked_byte = ss.peek_byte) && NUMBER_TABLE[peeked_byte]
ss.pos -= 1
output << [:number, ss.scan(NUMBER_LITERAL)]
else
output << special
end
else
output << special
end
elsif (sub_table = TWO_CHARS_COMPARISON_JUMP_TABLE[peeked])
ss.scan_byte
if (peeked_byte = ss.peek_byte) && (found = sub_table[peeked_byte])
output << found
ss.scan_byte
else
raise_syntax_error(start_pos, ss)
end
elsif (sub_table = COMPARISON_JUMP_TABLE[peeked])
ss.scan_byte
if (peeked_byte = ss.peek_byte) && (found = sub_table[peeked_byte])
output << found
ss.scan_byte
else
output << SINGLE_COMPARISON_TOKENS[peeked]
end
else
type, pattern = NEXT_MATCHER_JUMP_TABLE[peeked]
if type && (t = ss.scan(pattern))
# Special case for "contains"
output << if type == :id && t == "contains" && output.last&.first != :dot
COMPARISON_CONTAINS
else
[type, t]
end
else
raise_syntax_error(start_pos, ss)
end
end
end
# rubocop:enable Metrics/BlockNesting
output << EOS
rescue ::ArgumentError => e
if e.message == "invalid byte sequence in #{ss.string.encoding}"
raise SyntaxError, "Invalid byte sequence in #{ss.string.encoding}"
else
raise
end
end
def raise_syntax_error(start_pos, ss)
ss.pos = start_pos
# the character could be a UTF-8 character, use getch to get all the bytes
raise SyntaxError, "Unexpected character #{ss.getch}"
end
end
end
end
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