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lexer.rb
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lexer.rb
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# frozen_string_literal: true
module Prism
module Translation
class Parser
# Accepts a list of prism tokens and converts them into the expected
# format for the parser gem.
class Lexer
# The direct translating of types between the two lexers.
TYPES = {
# These tokens should never appear in the output of the lexer.
EOF: nil,
MISSING: nil,
NOT_PROVIDED: nil,
IGNORED_NEWLINE: nil,
EMBDOC_END: nil,
EMBDOC_LINE: nil,
__END__: nil,
# These tokens have more or less direct mappings.
AMPERSAND: :tAMPER2,
AMPERSAND_AMPERSAND: :tANDOP,
AMPERSAND_AMPERSAND_EQUAL: :tOP_ASGN,
AMPERSAND_DOT: :tANDDOT,
AMPERSAND_EQUAL: :tOP_ASGN,
BACK_REFERENCE: :tBACK_REF,
BACKTICK: :tXSTRING_BEG,
BANG: :tBANG,
BANG_EQUAL: :tNEQ,
BANG_TILDE: :tNMATCH,
BRACE_LEFT: :tLCURLY,
BRACE_RIGHT: :tRCURLY,
BRACKET_LEFT: :tLBRACK2,
BRACKET_LEFT_ARRAY: :tLBRACK,
BRACKET_LEFT_RIGHT: :tAREF,
BRACKET_LEFT_RIGHT_EQUAL: :tASET,
BRACKET_RIGHT: :tRBRACK,
CARET: :tCARET,
CARET_EQUAL: :tOP_ASGN,
CHARACTER_LITERAL: :tCHARACTER,
CLASS_VARIABLE: :tCVAR,
COLON: :tCOLON,
COLON_COLON: :tCOLON2,
COMMA: :tCOMMA,
COMMENT: :tCOMMENT,
CONSTANT: :tCONSTANT,
DOT: :tDOT,
DOT_DOT: :tDOT2,
DOT_DOT_DOT: :tDOT3,
EMBDOC_BEGIN: :tCOMMENT,
EMBEXPR_BEGIN: :tSTRING_DBEG,
EMBEXPR_END: :tSTRING_DEND,
EMBVAR: :tSTRING_DVAR,
EQUAL: :tEQL,
EQUAL_EQUAL: :tEQ,
EQUAL_EQUAL_EQUAL: :tEQQ,
EQUAL_GREATER: :tASSOC,
EQUAL_TILDE: :tMATCH,
FLOAT: :tFLOAT,
FLOAT_IMAGINARY: :tIMAGINARY,
FLOAT_RATIONAL: :tRATIONAL,
FLOAT_RATIONAL_IMAGINARY: :tIMAGINARY,
GLOBAL_VARIABLE: :tGVAR,
GREATER: :tGT,
GREATER_EQUAL: :tGEQ,
GREATER_GREATER: :tRSHFT,
GREATER_GREATER_EQUAL: :tOP_ASGN,
HEREDOC_START: :tSTRING_BEG,
HEREDOC_END: :tSTRING_END,
IDENTIFIER: :tIDENTIFIER,
INSTANCE_VARIABLE: :tIVAR,
INTEGER: :tINTEGER,
INTEGER_IMAGINARY: :tIMAGINARY,
INTEGER_RATIONAL: :tRATIONAL,
INTEGER_RATIONAL_IMAGINARY: :tIMAGINARY,
KEYWORD_ALIAS: :kALIAS,
KEYWORD_AND: :kAND,
KEYWORD_BEGIN: :kBEGIN,
KEYWORD_BEGIN_UPCASE: :klBEGIN,
KEYWORD_BREAK: :kBREAK,
KEYWORD_CASE: :kCASE,
KEYWORD_CLASS: :kCLASS,
KEYWORD_DEF: :kDEF,
KEYWORD_DEFINED: :kDEFINED,
KEYWORD_DO: :kDO,
KEYWORD_DO_LOOP: :kDO_COND,
KEYWORD_END: :kEND,
KEYWORD_END_UPCASE: :klEND,
KEYWORD_ENSURE: :kENSURE,
KEYWORD_ELSE: :kELSE,
KEYWORD_ELSIF: :kELSIF,
KEYWORD_FALSE: :kFALSE,
KEYWORD_FOR: :kFOR,
KEYWORD_IF: :kIF,
KEYWORD_IF_MODIFIER: :kIF_MOD,
KEYWORD_IN: :kIN,
KEYWORD_MODULE: :kMODULE,
KEYWORD_NEXT: :kNEXT,
KEYWORD_NIL: :kNIL,
KEYWORD_NOT: :kNOT,
KEYWORD_OR: :kOR,
KEYWORD_REDO: :kREDO,
KEYWORD_RESCUE: :kRESCUE,
KEYWORD_RESCUE_MODIFIER: :kRESCUE_MOD,
KEYWORD_RETRY: :kRETRY,
KEYWORD_RETURN: :kRETURN,
KEYWORD_SELF: :kSELF,
KEYWORD_SUPER: :kSUPER,
KEYWORD_THEN: :kTHEN,
KEYWORD_TRUE: :kTRUE,
KEYWORD_UNDEF: :kUNDEF,
KEYWORD_UNLESS: :kUNLESS,
KEYWORD_UNLESS_MODIFIER: :kUNLESS_MOD,
KEYWORD_UNTIL: :kUNTIL,
KEYWORD_UNTIL_MODIFIER: :kUNTIL_MOD,
KEYWORD_WHEN: :kWHEN,
KEYWORD_WHILE: :kWHILE,
KEYWORD_WHILE_MODIFIER: :kWHILE_MOD,
KEYWORD_YIELD: :kYIELD,
KEYWORD___ENCODING__: :k__ENCODING__,
KEYWORD___FILE__: :k__FILE__,
KEYWORD___LINE__: :k__LINE__,
LABEL: :tLABEL,
LABEL_END: :tLABEL_END,
LAMBDA_BEGIN: :tLAMBEG,
LESS: :tLT,
LESS_EQUAL: :tLEQ,
LESS_EQUAL_GREATER: :tCMP,
LESS_LESS: :tLSHFT,
LESS_LESS_EQUAL: :tOP_ASGN,
METHOD_NAME: :tFID,
MINUS: :tMINUS,
MINUS_EQUAL: :tOP_ASGN,
MINUS_GREATER: :tLAMBDA,
NEWLINE: :tNL,
NUMBERED_REFERENCE: :tNTH_REF,
PARENTHESIS_LEFT: :tLPAREN,
PARENTHESIS_LEFT_PARENTHESES: :tLPAREN_ARG,
PARENTHESIS_RIGHT: :tRPAREN,
PERCENT: :tPERCENT,
PERCENT_EQUAL: :tOP_ASGN,
PERCENT_LOWER_I: :tQSYMBOLS_BEG,
PERCENT_LOWER_W: :tQWORDS_BEG,
PERCENT_UPPER_I: :tSYMBOLS_BEG,
PERCENT_UPPER_W: :tWORDS_BEG,
PERCENT_LOWER_X: :tXSTRING_BEG,
PLUS: :tPLUS,
PLUS_EQUAL: :tOP_ASGN,
PIPE_EQUAL: :tOP_ASGN,
PIPE: :tPIPE,
PIPE_PIPE: :tOROP,
PIPE_PIPE_EQUAL: :tOP_ASGN,
QUESTION_MARK: :tEH,
REGEXP_BEGIN: :tREGEXP_BEG,
REGEXP_END: :tSTRING_END,
SEMICOLON: :tSEMI,
SLASH: :tDIVIDE,
SLASH_EQUAL: :tOP_ASGN,
STAR: :tSTAR2,
STAR_EQUAL: :tOP_ASGN,
STAR_STAR: :tPOW,
STAR_STAR_EQUAL: :tOP_ASGN,
STRING_BEGIN: :tSTRING_BEG,
STRING_CONTENT: :tSTRING_CONTENT,
STRING_END: :tSTRING_END,
SYMBOL_BEGIN: :tSYMBEG,
TILDE: :tTILDE,
UAMPERSAND: :tAMPER,
UCOLON_COLON: :tCOLON3,
UDOT_DOT: :tBDOT2,
UDOT_DOT_DOT: :tBDOT3,
UMINUS: :tUMINUS,
UMINUS_NUM: :tUNARY_NUM,
UPLUS: :tUPLUS,
USTAR: :tSTAR,
USTAR_STAR: :tPOW,
WORDS_SEP: :tSPACE
}
# These constants represent flags in our lex state. We really, really
# don't want to be using them and we really, really don't want to be
# exposing them as part of our public API. Unfortunately, we don't have
# another way of matching the exact tokens that the parser gem expects
# without them. We should find another way to do this, but in the
# meantime we'll hide them from the documentation and mark them as
# private constants.
EXPR_BEG = 0x1 # :nodoc:
EXPR_LABEL = 0x400 # :nodoc:
private_constant :TYPES, :EXPR_BEG, :EXPR_LABEL
# The Parser::Source::Buffer that the tokens were lexed from.
attr_reader :source_buffer
# An array of tuples that contain prism tokens and their associated lex
# state when they were lexed.
attr_reader :lexed
# A hash that maps offsets in bytes to offsets in characters.
attr_reader :offset_cache
# Initialize the lexer with the given source buffer, prism tokens, and
# offset cache.
def initialize(source_buffer, lexed, offset_cache)
@source_buffer = source_buffer
@lexed = lexed
@offset_cache = offset_cache
end
Range = ::Parser::Source::Range # :nodoc:
private_constant :Range
# Convert the prism tokens into the expected format for the parser gem.
def to_a
tokens = []
index = 0
length = lexed.length
while index < length
token, state = lexed[index]
index += 1
next if %i[IGNORED_NEWLINE __END__ EOF].include?(token.type)
type = TYPES.fetch(token.type)
value = token.value
location = Range.new(source_buffer, offset_cache[token.location.start_offset], offset_cache[token.location.end_offset])
case type
when :tCHARACTER
value.delete_prefix!("?")
when :tCOMMENT
if token.type == :EMBDOC_BEGIN
start_index = index
while !((next_token = lexed[index][0]) && next_token.type == :EMBDOC_END) && (index < length - 1)
value += next_token.value
index += 1
end
if start_index != index
value += next_token.value
location = Range.new(source_buffer, offset_cache[token.location.start_offset], offset_cache[lexed[index][0].location.end_offset])
index += 1
end
else
value.chomp!
location = Range.new(source_buffer, offset_cache[token.location.start_offset], offset_cache[token.location.end_offset - 1])
end
when :tNL
value = nil
when :tFLOAT
value = Float(value)
when :tIMAGINARY
value = parse_complex(value)
when :tINTEGER
if value.start_with?("+")
tokens << [:tUNARY_NUM, ["+", Range.new(source_buffer, offset_cache[token.location.start_offset], offset_cache[token.location.start_offset + 1])]]
location = Range.new(source_buffer, offset_cache[token.location.start_offset + 1], offset_cache[token.location.end_offset])
end
value = Integer(value)
when :tLABEL
value.chomp!(":")
when :tLABEL_END
value.chomp!(":")
when :tLCURLY
type = :tLBRACE if state == EXPR_BEG | EXPR_LABEL
when :tNTH_REF
value = Integer(value.delete_prefix("$"))
when :tOP_ASGN
value.chomp!("=")
when :tRATIONAL
value = parse_rational(value)
when :tSPACE
value = nil
when :tSTRING_BEG
if ["\"", "'"].include?(value) && (next_token = lexed[index][0]) && next_token.type == :STRING_END
next_location = token.location.join(next_token.location)
type = :tSTRING
value = ""
location = Range.new(source_buffer, offset_cache[next_location.start_offset], offset_cache[next_location.end_offset])
index += 1
elsif ["\"", "'"].include?(value) && (next_token = lexed[index][0]) && next_token.type == :STRING_CONTENT && next_token.value.lines.count <= 1 && (next_next_token = lexed[index + 1][0]) && next_next_token.type == :STRING_END
next_location = token.location.join(next_next_token.location)
type = :tSTRING
value = next_token.value
location = Range.new(source_buffer, offset_cache[next_location.start_offset], offset_cache[next_location.end_offset])
index += 2
elsif value.start_with?("<<")
quote = value[2] == "-" || value[2] == "~" ? value[3] : value[2]
value = "<<#{quote == "'" || quote == "\"" ? quote : "\""}"
end
when :tSTRING_CONTENT
unless (lines = token.value.lines).one?
start_offset = offset_cache[token.location.start_offset]
lines.map do |line|
end_offset = start_offset + line.length
tokens << [:tSTRING_CONTENT, [line, Range.new(source_buffer, offset_cache[start_offset], offset_cache[end_offset])]]
start_offset = end_offset
end
next
end
when :tSTRING_DVAR
value = nil
when :tSTRING_END
if token.type == :HEREDOC_END && value.end_with?("\n")
newline_length = value.end_with?("\r\n") ? 2 : 1
value = value.sub(/\r?\n\z/, '')
location = Range.new(source_buffer, offset_cache[token.location.start_offset], offset_cache[token.location.end_offset - newline_length])
elsif token.type == :REGEXP_END
value = value[0]
location = Range.new(source_buffer, offset_cache[token.location.start_offset], offset_cache[token.location.start_offset + 1])
end
when :tSYMBEG
if (next_token = lexed[index][0]) && next_token.type != :STRING_CONTENT && next_token.type != :EMBEXPR_BEGIN && next_token.type != :EMBVAR
next_location = token.location.join(next_token.location)
type = :tSYMBOL
value = next_token.value
value = { "~@" => "~", "!@" => "!" }.fetch(value, value)
location = Range.new(source_buffer, offset_cache[next_location.start_offset], offset_cache[next_location.end_offset])
index += 1
end
when :tFID
if !tokens.empty? && tokens.dig(-1, 0) == :kDEF
type = :tIDENTIFIER
end
end
tokens << [type, [value, location]]
if token.type == :REGEXP_END
tokens << [:tREGEXP_OPT, [token.value[1..], Range.new(source_buffer, offset_cache[token.location.start_offset + 1], offset_cache[token.location.end_offset])]]
end
end
tokens
end
private
# Parse a complex from the string representation.
def parse_complex(value)
value.chomp!("i")
if value.end_with?("r")
Complex(0, parse_rational(value))
elsif value.start_with?(/0[BbOoDdXx]/)
Complex(0, Integer(value))
else
Complex(0, value)
end
end
# Parse a rational from the string representation.
def parse_rational(value)
value.chomp!("r")
if value.start_with?(/0[BbOoDdXx]/)
Rational(Integer(value))
else
Rational(value)
end
end
end
end
end
end