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require "proc_to_ast/version"
require "parser/current"
require "unparser"
require "rouge"
module ProcToAst
class MultiMatchError < StandardError; end
class Parser
attr_reader :parser
@formatter = Rouge::Formatters::Terminal256.new
@lexer = Rouge::Lexers::Ruby.new
class << self
def highlight(source)
@formatter.format(@lexer.lex(source))
end
end
def initialize
@parser = ::Parser::CurrentRuby.default_parser
@parser.diagnostics.consumer = ->(diagnostic) {} # suppress error message
end
# Read file and try parsing
# if success parse, find proc AST
#
# @param filename [String] reading file path
# @param linenum [Integer] start line number
# @return [Parser::AST::Node] Proc AST
def parse(filename, linenum)
@filename, @linenum = filename, linenum
buf = []
File.open(filename, "rb").each_with_index do |line, index|
next if index < linenum - 1
buf << line
begin
return do_parse(buf.join)
rescue ::Parser::SyntaxError
node = trim_and_retry(buf)
return node if node
end
end
fail(::Parser::SyntaxError, "Unknown error")
end
private
def do_parse(source)
parser.reset
source_buffer = ::Parser::Source::Buffer.new(@filename, @linenum)
source_buffer.source = source
node = parser.parse(source_buffer)
block_nodes = traverse_node(node)
if block_nodes.length == 1
block_nodes.first
else
raise ProcToAst::MultiMatchError
end
end
# Remove tail comma and wrap dummy method, and retry parsing
# For proc inner Array or Hash
def trim_and_retry(buf)
*lines, last = buf
# For inner Array or Hash or Arguments list.
lines << last.gsub(/,\s*$/, "")
do_parse("a(#{lines.join})") # wrap dummy method
rescue ::Parser::SyntaxError
end
def traverse_node(node)
if node.type != :block
node.children.flat_map { |child|
if child.is_a?(AST::Node)
traverse_node(child)
end
}.compact
else
[node]
end
end
end
end
class Proc
# @return [Parser::AST::Node] Proc AST
def to_ast
filename, linenum = source_location
parser = ProcToAst::Parser.new
parser.parse(filename, linenum)
end
# @param highlight [Boolean] enable output highlight
# @return [String] proc source code
def to_source(highlight: false)
source = Unparser.unparse(to_ast)
if highlight
ProcToAst::Parser.highlight(source)
else
source
end
end
def to_raw_source(highlight: false)
source = to_ast.loc.expression.source.force_encoding("UTF-8")
if highlight
ProcToAst::Parser.highlight(source)
else
source
end
end
end
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