16 files changed, 48 insertions(+), 50 deletions(-)

M .rubocop.yml
M Gemfile
M bin/scheme
M compiler.rb
M compiler/lib/scheme/base.rb
M compiler/libraries.rb
M compiler/macro.rb
M parser.rb
M spec/lib_spec.rb
M spec/support/dumpable_string_io.rb
M vm.rb
M vm/debug_output.rb
M vm/gc.rb
M vm/int.rb
M vm/operations.rb
M vm/pair.rb

@@ 7,6 7,9 @@ Style/WordArray:
 Style/PerlBackrefs:
   Enabled: false
 
+Style/IndentArray:
+  Enabled: false
+
 Metrics/LineLength:
   Max: 120
 

@@ 4,7 4,7 @@ gem 'parslet'
 gem 'pry'
 
 group :development do
-  gem 'rspec'
   gem 'pry-stack_explorer'
+  gem 'rspec'
   gem 'stackprof'
 end

@@ 6,7 6,7 @@ require_relative '../program'
 options = { debug: 0 }
 opt_parser = OptionParser.new do |opts|
   opts.banner = "Usage: scheme [options] path [arguments]\n" \
-                "       scheme [options] -e \"(print (+ 2 2))\" [arguments]"
+                '       scheme [options] -e "(print (+ 2 2))" [arguments]'
 
   opts.on('-e SCRIPT', 'Execute script passed as argument') do |script|
     options[:script] = script

@@ 10,7 10,7 @@ require 'pry'
 
 class Compiler
   ROOT_PATH = VM::ROOT_PATH
-  LOAD_PATH = [File.join(ROOT_PATH, 'lib'), File.join(ROOT_PATH, 'spec')]
+  LOAD_PATH = [File.join(ROOT_PATH, 'lib'), File.join(ROOT_PATH, 'spec')].freeze
 
   include Compiler::Libraries
   include Compiler::Lib::Scheme::Base


@@ 99,7 99,7 @@ class Compiler
     elsif options[:locals][name]
       call(sexp, options)
     else
-      fail VM::VariableUndefined, name
+      raise VM::VariableUndefined, name
     end
   end
 


@@ 118,7 118,7 @@ class Compiler
     (name, *args) = sexp
     expr = compile_sexp(args.first, options.merge(quasiquote: false))
     if name == 'unquote-splicing'
-      fail 'can only use unquote-splicing with a list' if expr.compact.last != VM::PUSH_LIST
+      raise 'can only use unquote-splicing with a list' if expr.compact.last != VM::PUSH_LIST
       ['splice', expr.first]
     else
       expr


@@ 219,7 219,7 @@ class Compiler
   end
 
   def push_var(name, options)
-    fail VM::VariableUndefined, name unless options[:locals][name]
+    raise VM::VariableUndefined, name unless options[:locals][name]
     [
       VM::PUSH_VAR,
       name


@@ 245,12 245,12 @@ class Compiler
   end
 
   def parse_file(filename, relative_to: nil)
-    if filename =~ /\A\./ && relative_to
-      path = File.join(File.dirname(relative_to), filename)
-    else
-      path = @load_path.map { |p| File.join(p, filename) }.detect { |p| File.exist?(p) }
-    end
-    fail "File #{filename} not found in load path #{@load_path.join(';')}" unless path
+    path = if filename.start_with?('.') && relative_to
+             File.join(File.dirname(relative_to), filename)
+           else
+             @load_path.map { |p| File.join(p, filename) }.detect { |p| File.exist?(p) }
+           end
+    raise "File #{filename} not found in load path #{@load_path.join(';')}" unless path
     code = File.read(path)
     @source[filename] = code
     Parser.new(code, filename: filename).parse

@@ 12,7 12,7 @@ class Compiler
         end
 
         def base_apply((lambda, *args), options)
-          fail 'apply expects at least 2 arguments' if args.empty?
+          raise 'apply expects at least 2 arguments' if args.empty?
           [
             args.map { |arg| compile_sexp(arg, options.merge(use: true)) },
             VM::PUSH_NUM, args.size,


@@ 56,7 56,7 @@ class Compiler
         end
 
         def base_cons(args, options)
-          fail 'cons expects exactly 2 arguments' if args.size != 2
+          raise 'cons expects exactly 2 arguments' if args.size != 2
           [
             args.map { |arg| compile_sexp(arg, options.merge(use: true)) },
             VM::PUSH_CONS,

@@ 12,7 12,7 @@ class Compiler
 
     def do_include(paths, relative_to, options)
       paths.map do |path|
-        fail "include expects a string, but got #{path.inspect}" unless path =~ /\A"(.+)?"\z/
+        raise "include expects a string, but got #{path.inspect}" unless path =~ /\A"(.+)?"\z/
         filename = "#{$1}.scm"
         sexps = parse_file(filename, relative_to: relative_to)
         compile_sexps(sexps, options: options)


@@ 69,7 69,7 @@ class Compiler
           [name, internal_name, renamed[external_name] || external_name, syntax]
         end
       else
-        fail "unknown import directive #{directive}"
+        raise "unknown import directive #{directive}"
       end
       [include, bindings]
     end

@@ 23,7 23,7 @@ class Compiler
         values = Pattern.new(pattern, literals: @literals).match(sexp)
         return [values, template] if values
       end
-      fail "Could not match any template for #{sexp.inspect}"
+      raise "Could not match any template for #{sexp.inspect}"
     end
 
     def expand_template(template)

@@ 71,7 71,7 @@ module LISP
       ',@' => 'unquote-splicing',
       ','  => 'unquote',
       '`'  => 'quasiquote'
-    }
+    }.freeze
 
     rule(comment: subtree(:comment))
 

@@ 27,7 27,7 @@ Dir[File.expand_path('../lib/**/*.scm', __FILE__)].each do |path|
         puts result
         failed = true
       end
-      fail 'spec failed' if failed
+      raise 'spec failed' if failed
     end
   end
 end

@@ 4,6 4,5 @@ class DumpableStringIO < StringIO
     []
   end
 
-  def marshal_load(_data)
-  end
+  def marshal_load(_data); end
 end

@@ 79,7 79,7 @@ class VM
     ['IMPORT_LIB',    3],
     ['HALT',          0],
     ['DEBUG',         0]
-  ]
+  ].freeze
 
   INSTRUCTIONS.each_with_index do |(name, _arity), index|
     const_set(name.to_sym, index)


@@ 96,7 96,7 @@ class VM
     VM::EmptyList,
     VM::Int,
     VM::Pair
-  ]
+  ].freeze
 
   attr_reader :stack, :heap, :ip, :call_stack, :closures, :call_args, :libs, :last_atom
   attr_accessor :stdout, :debug


@@ 130,7 130,7 @@ class VM
     debug_output.print_ip if debug >= 2
     case instruction
     when NOOP
-      # nothing
+      :noop
     when RETURN
       do_return(debug)
     when DEBUG


@@ 143,7 143,7 @@ class VM
   end
 
   def fetch
-    fail "heap[#{@ip}] is not executable" unless executable?(@ip)
+    raise "heap[#{@ip}] is not executable" unless executable?(@ip)
     instruction = @heap[@ip]
     @ip += 1
     instruction


@@ 165,7 165,7 @@ class VM
 
   def resolve(address)
     return Unspecified.instance if address.nil?
-    @heap[address] || fail("invalid address #{address}")
+    @heap[address] || raise("invalid address #{address}")
   end
 
   def push(address)


@@ 316,7 316,7 @@ class VM
   def return_value
     if peek
       val = pop_raw
-      return val if val.is_a?(Fixnum)
+      return val if val.is_a?(Integer)
       return 1 if val == false
     end
     0

@@ 60,10 60,9 @@ class VM
     def print_stack
       print 'stack:  '
       puts @vm.stack.map { |a| a ? @vm.heap[a].inspect : a.inspect }.join("\n" + (' ' * 28))
-      if (atom = @vm.last_atom)
-        print 'code:  '.rjust(28)
-        puts "#{atom.filename}##{atom.line}:#{atom.column}"
-      end
+      return unless (atom = @vm.last_atom)
+      print 'code:  '.rjust(28)
+      puts "#{atom.filename}##{atom.line}:#{atom.column}"
     end
   end
 end

@@ 9,7 9,7 @@ class VM
         next if value.nil?
         next if active?(location)
         puts "garbage collecting #{value.inspect} at #{location}" if debug >= 3
-        fail "heap[#{@ip}] is not writable" unless @vm.writable?(location)
+        raise "heap[#{@ip}] is not writable" unless @vm.writable?(location)
         @vm.heap[location] = nil
       end
     end

@@ 7,7 7,7 @@ class VM
 
     def initialize(num)
       @num = num.to_i
-      fail 'integer out of range' if @num < MIN || @num > MAX
+      raise 'integer out of range' if @num < MIN || @num > MAX
     end
 
     def raw


@@ 19,8 19,8 @@ class VM
       raw == other.raw
     end
 
-    alias_method :==, :eq?
-    alias_method :eqv?, :eq?
+    alias == eq?
+    alias eqv? eq?
 
     def +(other)
       Int.new(raw + other.raw)

@@ 58,7 58,7 @@ class VM
     def do_push_local
       name = fetch
       address = named_args[name] || locals[name]
-      fail VariableUndefined, name unless address
+      raise VariableUndefined, name unless address
       push(address)
     end
 


@@ 72,13 72,13 @@ class VM
         address = c[:locals][name]
         push(address)
       else
-        fail VariableUndefined, name
+        raise VariableUndefined, name
       end
     end
 
     def do_push_args
       last = empty_list
-      while args.size > 0
+      until args.empty?
         arg = args.pop
         address = alloc
         @heap[address] = build_pair(arg, last)


@@ 141,7 141,7 @@ class VM
         @call_stack << { func: new_ip, return: @ip, args: @call_args, named_args: {} }
       end
       pp @call_stack if @call_stack.size > MAX_CALL_DEPTH
-      fail CallStackTooDeep, 'call stack too deep' if @call_stack.size > MAX_CALL_DEPTH
+      raise CallStackTooDeep, 'call stack too deep' if @call_stack.size > MAX_CALL_DEPTH
       @ip = new_ip
     end
 


@@ 153,7 153,7 @@ class VM
       end
       new_ip = pop
       @call_stack << { func: new_ip, return: @ip, args: @call_args, named_args: {} }
-      fail CallStackTooDeep, 'call stack too deep' if @call_stack.size > MAX_CALL_DEPTH
+      raise CallStackTooDeep, 'call stack too deep' if @call_stack.size > MAX_CALL_DEPTH
       @ip = new_ip
     end
 


@@ 283,7 283,7 @@ class VM
 
     def do_append
       count = pop_raw
-      if count == 0
+      if count.zero?
         push(empty_list)
       else
         raw = (0...count).map { pop_val }.reverse.map(&:to_a).inject(&:+)


@@ 300,10 300,10 @@ class VM
     def do_raw
       raw = pop_raw
       case raw
-      when Fixnum
+      when Integer
         push_val(VM::Int.new(raw))
       else
-        fail "unknown raw value type #{raw.inspect}"
+        raise "unknown raw value type #{raw.inspect}"
       end
     end
 


@@ 319,17 319,14 @@ class VM
       elsif (c = find_closure_with_symbol(name))
         c[:locals][name] = pop
       else
-        fail VariableUndefined, name
+        raise VariableUndefined, name
       end
     end
 
     def do_set_args
       count = pop_raw
-      if @stack.size >= count
-        @call_args = (0...count).map { pop }.reverse
-      else
-        fail NoStackValue, "stack size is #{@stack.size}, but you tried to use #{count}"
-      end
+      raise NoStackValue, "stack size is #{@stack.size}, but you tried to use #{count}" if @stack.size < count
+      @call_args = (0...count).map { pop }.reverse
     end
 
     def do_set_arg

@@ 17,7 17,7 @@ class VM
 
     def to_s
       items = to_a.flat_map do |item|
-        if item.is_a?(Fixnum) # address
+        if item.is_a?(Integer) # address
           @heap[item].to_s
         else
           ['.', item.to_s]