ruby_syntax_fuzzer.rb

require 'prism'
require 'ripper'
chars = %w[1 % = a b == * . ( ) , % ? ** & [ ] { } | ; : => ~ ! ^ || && '' .. ... < > + $a @a] + [' ', "\n", ' if ', ' and ',' rescue ', ' in ']
p seed: seed = rand(10000)
srand seed
$VERBOSE=nil
(3..10).each do |n|
  [chars.size**n, 100000].min.times do |i|
    code = n.times.map{chars.sample}.join
    p [n, i] if i % 1000 == 0
    debug = false
    next if code =~ /\{\s*<<[-~]?[a-zA-Z1']/
    # next unless n==6 && i > 50400; debug=1
    [
      "b=1;#{code}",
      "(#{code})",
      "p{|#{code}|}",
      "def f(#{code});end",
      "*x=#{code}",
      "b=1 if #{code}",
      "#{code} if 1",
      "class #{code}; end",
      "def (#{code}).f; end",
      "1 rescue #{code}",
      "begin; #{code} rescue 1; end",
      "1 in #{code};",
      "class A<#{code}; end",
      "class <<#{code}; end",
      "for a in #{code}; end",
      "def f x=...#{code}; end",
      "p 1, #{code}",
      "{#{code}=>1}",
      "{a:#{code}}",
      "->#{code}{}",
      "def f(...);b=1;#{code};end",
      "def f(*,**,&);b=1;#{code};end",
      "def f(b)=#{code}",
    ].each do |code2|
      next if code2 =~ /(in|=>).*\*\s*([a-z][a-z\d]*)?\s*,/m
      next if code2 =~ /:\s*\(\s*\*/
      next if code2 =~ /\{.+:.*\(\s*\*/
      next if code2 =~ /\n\s*\*[a-z]*\s*\)/
      p code2 if debug
      # begin; RubyVM::InstructionSequence.compile(code2); rescue SyntaxError; end
      p code2 if !!Ripper.sexp(code2) != Prism.parse_success?(code2)
    end
  end
end