Module: Fast

Defined in:
lib/fast.rb,
lib/fast/cli.rb,
lib/fast/version.rb,
lib/fast/rewriter.rb,
lib/fast/shortcut.rb,
lib/fast/experiment.rb

Overview

Allow to replace code managing multiple replacements and combining replacements. Useful for large codebase refactor and multiple replacements in the same file.

Defined Under Namespace

Classes: All, Any, Capture, Cli, Experiment, ExperimentCombinations, ExperimentFile, ExpressionParser, Find, FindFromArgument, FindString, FindWithCapture, InstanceMethodCall, Matcher, Maybe, MethodCall, Not, Parent, Rewriter, Shortcut

Constant Summary collapse

LITERAL =

Literals are shortcuts allowed inside ExpressionParser

{
  '...' => ->(node) { node&.children&.any? },
  '_' => ->(node) { !node.nil? },
  'nil' => nil
}.freeze
TOKENIZER =

Allowed tokens in the node pattern domain

%r/
  [\+\-\/\*\\!]         # operators or negation
  |
  ===?                  # == or ===
  |
  \d+\.\d*              # decimals and floats
  |
  "[^"]+"               # strings
  |
  _                     # something not nil: match
  |
  \.{3}                 # a node with children: ...
  |
  \[|\]                 # square brackets `[` and `]` for all
  |
  \^                    # node has children with
  |
  \?                    # maybe expression
  |
  [\d\w_]+[\\!\?]?      # method names or numbers
  |
  \(|\)                 # parens `(` and `)` for tuples
  |
  \{|\}                 # curly brackets `{` and `}` for any
  |
  \$                    # capture
  |
  \#\w[\d\w_]+[\\!\?]?  # custom method call
  |
  \.\w[\d\w_]+\?       # instance method call
  |
  \\\d                  # find using captured expression
  |
  %\d                   # bind extra arguments to the expression
/x.freeze
VERSION = 
'0.1.5'
LOOKUP_FAST_FILES_DIRECTORIES =

Where to search for Fastfile archives?

  1. Current directory that the command is being runned

  2. Home folder

  3. Using the FAST_FILE_DIR variable to set an extra folder

[Dir.pwd, ENV['HOME'], ENV['FAST_FILE_DIR']].freeze

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.debugging ⇒ Object

Returns the value of attribute debugging.



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# File 'lib/fast.rb', line 172

def debugging
  @debugging
end

.experiments ⇒ Object (readonly)

Returns the value of attribute experiments.



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# File 'lib/fast/experiment.rb', line 30

def experiments
  @experiments
end

Class Method Details

.ast(content, buffer_name: '(string)') ⇒ Astrolabe::Node

Returns from the parsed content.

Examples:

Fast.ast("1") # => s(:int, 1)
Fast.ast("a.b") # => s(:send, s(:send, nil, :a), :b)

Returns:

  • (Astrolabe::Node) —

    from the parsed content



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# File 'lib/fast.rb', line 75

def ast(content, buffer_name: '(string)')
  buffer = Parser::Source::Buffer.new(buffer_name)
  buffer.source = content
  Parser::CurrentRuby.new(Astrolabe::Builder.new).parse(buffer)
end

.ast_from_file(file) ⇒ Astrolabe::Node

caches the content based on the filename.

Examples:

Fast.ast_from_file("example.rb") # => s(...)

Returns:

  • (Astrolabe::Node) —

    parsed from file content



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# File 'lib/fast.rb', line 85

def ast_from_file(file)
  @cache ||= {}
  @cache[file] ||= ast(IO.read(file), buffer_name: file)
end

.capture(pattern, node) ⇒ Array<Object>, Object

Return only captures from a search

Returns:

  • (Array<Object>) —

    with all captured elements.

  • (Object) —

    with single element when single capture.



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# File 'lib/fast.rb', line 156

def capture(pattern, node)
  res = if (match = match?(pattern, node))
          match == true ? node : match
        else
          node.each_child_node
            .flat_map { |child| capture(pattern, child) }
            .compact.flatten
        end
  res = [res] unless res.is_a?(Array)
  res.one? ? res.first : res
end

.capture_all(pattern, locations = ['.']) ⇒ Hash<String,Object>

Capture with pattern on a directory or multiple files

Parameters:

  • pattern (String)
  • locations (Array<String>) (defaults to: ['.']) —

    where to search. Default is ‘.’

Returns:

  • (Hash<String,Object>) —

    with files and captures



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# File 'lib/fast.rb', line 119

def capture_all(pattern, locations = ['.'])
  capture_pattern = method(:capture_file).curry.call(pattern)
  group_results(capture_pattern, locations)
end

.capture_file(pattern, file) ⇒ Array<Object>

Capture elements from searches in files. Keep in mind you need to use ‘$` in the pattern to make it work.

Returns:

  • (Array<Object>) —

    captured from the pattern matched in the file



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# File 'lib/fast.rb', line 134

def capture_file(pattern, file)
  capture pattern, ast_from_file(file)
end

.debug ⇒ Object

Utility function to inspect search details using debug block.

It prints output of all matching cases.

int == (int 1) # => true
1 == 1 # => true

Examples:

Fast.debug do
   Fast.match?([:int, 1], s(:int, 1))
end



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# File 'lib/fast.rb', line 184

def debug
  return yield if debugging

  self.debugging = true
  result = nil
  Find.class_eval do
    alias_method :original_match_recursive, :match_recursive
    alias_method :match_recursive, :debug_match_recursive
    result = yield
    alias_method :match_recursive, :original_match_recursive # rubocop:disable Lint/DuplicateMethods
  end
  self.debugging = false
  result
end

.experiment(name, &block) ⇒ Object

Fast.experiment is a shortcut to define new experiments and allow them to work together in experiment combinations.

The following experiment look into spec folder and try to remove before and after blocks on testing code. Sometimes they’re not effective and we can avoid the hard work of do it manually.

If the spec does not fail, it keeps the change.

Examples:

Remove useless before and after block

Fast.experiment("RSpec/RemoveUselessBeforeAfterHook") do
  lookup 'spec'
  search "(block (send nil {before after}))"
  edit { |node| remove(node.loc.expression) }
  policy { |new_file| system("rspec --fail-fast #{new_file}") }
end



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# File 'lib/fast/experiment.rb', line 25

def experiment(name, &block)
  @experiments ||= {}
  @experiments[name] = Experiment.new(name, &block)
end

.expression(string) ⇒ Object 



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# File 'lib/fast.rb', line 168

def expression(string)
  ExpressionParser.new(string).parse
end

.expression_from(node) ⇒ String

Extracts a node pattern expression from a given node supressing identifiers and primitive types. Useful to index abstract patterns or similar code structure.

Examples:

Fast.expression_from(Fast.ast('1')) # => '(int _)'
Fast.expression_from(Fast.ast('a = 1')) # => '(lvasgn _ (int _))'
Fast.expression_from(Fast.ast('def name; person.name end')) # => '(def _ (args) (send (send nil _) _))'

Parameters:

  • node (Astrolabe::Node)

Returns:

  • (String) —

    with an pattern to search from it.

See Also:



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# File 'lib/fast.rb', line 222

def expression_from(node)
  case node
  when Parser::AST::Node
    children_expression = node.children.map(&method(:expression_from)).join(' ')
    "(#{node.type}#{' ' + children_expression if node.children.any?})"
  when nil, 'nil'
    'nil'
  when Symbol, String, Numeric
    '_'
  end
end

.fast_files ⇒ Array<String>

Returns with existent Fastfiles from LOOKUP_FAST_FILES_DIRECTORIES.

Returns:



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# File 'lib/fast/shortcut.rb', line 29

def fast_files
  @fast_files ||= LOOKUP_FAST_FILES_DIRECTORIES.compact
    .map { |dir| File.join(dir, 'Fastfile') }
    .select(&File.method(:exists?))
end

.group_results(search_pattern, locations) ⇒ Object 



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# File 'lib/fast.rb', line 124

def group_results(search_pattern, locations)
  ruby_files_from(*locations)
    .map { |f| { f => search_pattern.call(f) } }
    .reject { |results| results.values.all?(&:empty?) }
    .inject(&:merge!)
end

.highlight(node, show_sexp: false, colorize: true) ⇒ Object

Highligh some source code based on the node. Useful for printing code with syntax highlight.

Parameters:

  • show_sexp (Boolean) (defaults to: false) —

    prints node expression instead of code

  • colorize (Boolean) (defaults to: true) —

    skips CodeRay processing when false.



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# File 'lib/fast/cli.rb', line 19

def highlight(node, show_sexp: false, colorize: true)
  output =
    if node.respond_to?(:loc) && !show_sexp
      node.loc.expression.source
    else
      node
    end
  return output unless colorize

  CodeRay.scan(output, :ruby).term
end

.load_fast_files! ⇒ Object

Loads Fastfiles from fast_files list



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# File 'lib/fast/shortcut.rb', line 36

def load_fast_files!
  fast_files.each(&method(:load))
end

.match?(pattern, ast, *args) ⇒ Boolean

Verify if a given AST matches with a specific pattern

Examples:

Fast.match?("int", Fast.ast("1")) # => true

Returns:

  • (Boolean) —

    case matches ast with the current expression



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# File 'lib/fast.rb', line 94

def match?(pattern, ast, *args)
  Matcher.new(pattern, ast, *args).match?
end

.replace(pattern, ast, source = nil, &replacement) ⇒ String

Replaces content based on a pattern.

Examples:

Fast.replace?(Fast.ast("a = 1"),"lvasgn") do |node|
  replace(node.location.name, 'variable_renamed')
end # => variable_renamed = 1

Parameters:

  • ast (Astrolabe::Node) —

    with the current AST to search.

  • pattern (String) —

    with the expression to be targeting nodes.

  • replacement (Proc) —

    gives the [Rewriter] context in the block.

Returns:

  • (String) —

    with the new source code after apply the replacement

See Also:



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# File 'lib/fast/rewriter.rb', line 17

def replace(pattern, ast, source = nil, &replacement)
  rewriter_for(pattern, ast, source, &replacement).rewrite!
end

.replace_file(pattern, file, &replacement) ⇒ Object

Replaces the source of an ast_from_file with and the same source if the pattern does not match.



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# File 'lib/fast/rewriter.rb', line 33

def replace_file(pattern, file, &replacement)
  ast = ast_from_file(file)
  replace(pattern, ast, IO.read(file), &replacement)
end

.report(result, show_sexp: false, file: nil, headless: false, colorize: true) ⇒ Object

Combines highlight with files printing file name in the head with the source line.

Examples:

Fast.highlight(Fast.search(...))

Parameters:

  • result (Astrolabe::Node)
  • show_sexp (Boolean) (defaults to: false) —

    Show string expression instead of source

  • file (String) (defaults to: nil) —

    Show the file name and result line before content

  • headless (Boolean) (defaults to: false) —

    Skip printing the file name and line before content



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# File 'lib/fast/cli.rb', line 39

def report(result, show_sexp: false, file: nil, headless: false, colorize: true)
  if file
    line = result.loc.expression.line if result.is_a?(Parser::AST::Node)
    puts(highlight("# #{file}:#{line}", colorize: colorize)) unless headless
  end
  puts highlight(result, show_sexp: show_sexp, colorize: colorize)
end

.rewrite_file(pattern, file, &replacement) ⇒ Object

Combines #replace_file output overriding the file if the output is different from the original file content.



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# File 'lib/fast/rewriter.rb', line 40

def rewrite_file(pattern, file, &replacement)
  previous_content = IO.read(file)
  content = replace_file(pattern, file, &replacement)
  File.open(file, 'w+') { |f| f.puts content } if content != previous_content
end

.rewriter_for(pattern, ast, source = nil, &replacement) ⇒ Fast::Rewriter

Returns:



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# File 'lib/fast/rewriter.rb', line 22

def rewriter_for(pattern, ast, source = nil, &replacement)
  rewriter = Rewriter.new
  rewriter.source = source
  rewriter.ast = ast
  rewriter.search = pattern
  rewriter.replacement = replacement
  rewriter
end

.ruby_files_from(*files) ⇒ Array<String>

When the argument is a folder, it recursively fetches all .rb files from it.

Parameters:

  • files —

    can be file paths or directories.

Returns:

  • (Array<String>) —

    with all ruby files from arguments.



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# File 'lib/fast.rb', line 202

def ruby_files_from(*files)
  directories = files.select(&File.method(:directory?))

  if directories.any?
    files -= directories
    files |= directories.flat_map { |dir| Dir["#{dir}/**/*.rb"] }
    files.uniq!
  end
  files
end

.search(pattern, node) { ... } ⇒ Object

Search recursively into a node and its children. If the node matches with the pattern it returns the node, otherwise it recursively collect possible children nodes

Yields:

  • node and capture if block given



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# File 'lib/fast.rb', line 142

def search(pattern, node)
  if (match = match?(pattern, node))
    yield node, match if block_given?
    match != true ? [node, match] : [node]
  else
    node.each_child_node
      .flat_map { |child| search(pattern, child) }
      .compact.flatten
  end
end

.search_all(pattern, locations = ['.']) ⇒ Hash<String,Array<Astrolabe::Node>>

Search with pattern on a directory or multiple files

Parameters:

  • pattern (String)
  • *locations (Array<String>) —

    where to search. Default is ‘.’

Returns:

  • (Hash<String,Array<Astrolabe::Node>>) —

    with files and results



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# File 'lib/fast.rb', line 110

def search_all(pattern, locations = ['.'])
  search_pattern = method(:search_file).curry.call(pattern)
  group_results(search_pattern, locations)
end

.search_file(pattern, file) ⇒ Array<Astrolabe::Node>

Search with pattern directly on file

Returns:

  • (Array<Astrolabe::Node>) —

    that matches the pattern



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# File 'lib/fast.rb', line 100

def search_file(pattern, file)
  node = ast_from_file(file)
  return [] if node.nil?
  search pattern, node
end

.shortcut(identifier, *args, &block) ⇒ Object

Store predefined searches with default paths through shortcuts. define your Fastfile in you root folder or

Examples:

Shortcut for finding validations in rails models

Fast.shortcut(:validations, "(send nil {validate validates})", "app/models")



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# File 'lib/fast/shortcut.rb', line 16

def shortcut(identifier, *args, &block)
  puts "identifier #{identifier.inspect} will be override" if shortcuts.key?(identifier)
  shortcuts[identifier] = Shortcut.new(*args, &block)
end

.shortcuts ⇒ Hash<String,Shortcut>

Stores shortcuts in a simple hash where the key is the identifier and the value is the object itself.

Returns:

  • (Hash<String,Shortcut>) —

    as a dictionary.



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# File 'lib/fast/shortcut.rb', line 24

def shortcuts
  @shortcuts ||= {}
end