Module: RubyLabs::Source

Defined in:
lib/rubylabs.rb

Overview

Source

The Source module provides access the source code for a lab project. When IRB reads the modules from a file, the source is saved in a global array named SCRIPT_LINES__. The methods defined in this module scan the source code to look for tags that mark the first and last lines of methods described in the book.

A method name can be passed either as a String or a Symbol. For example, to print a listing of the isort method a user can call

Source.listing("isort")

or

Source.listing(:isort)

#– Code that will be accessed by methods in this module should be delimited by :begin and :end tags. See the definition of isort in iterationlab.rb for an example of how to name a method and its helper methods.

Constant Summary collapse

@@probes = 
Hash.new
@@file = 
Hash.new
@@size = 
Hash.new
@@base = 
Hash.new
@@helpers = 
Hash.new
@@line = 
nil

Class Method Summary collapse

Class Method Details

.checkout(name, newfilename = nil) ⇒ Object

Save a copy of the source code for method name in a file. If a file name is not specified, the output file name is the name of the method with “.rb” appended. Prompts the user before overwriting an existing file.

Example – Write the source for the method isort to “isort.rb”:

Source.checkout("isort")

Example – Write the source for isort to “mysort.rb”

Source.checkout("isort", "mysort.rb")

:call-seq:

Source.checkout(name)



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# File 'lib/rubylabs.rb', line 485

def Source.checkout(name, newfilename = nil)
  begin
    id = Source.find(name)
    if newfilename.nil?
      newfilename = id.to_s
    end
    if newfilename[-1] == ?? || newfilename[1] == ?!
      newfilename.chop!
    end
    if newfilename !~ /\.rb$/
      newfilename += ".rb"
    end
    if File.exists?(newfilename)
      print "Replace existing #{newfilename}? [yn] "
      if STDIN.gets[0] != ?y
        puts "File not written"
        return false
      end
    end
    File.open(newfilename, "w") do |f|
      f.puts "# #{name} method exported from #{File.basename(@@file[id])}"
      f.puts
      Source.print_source(f, id)
      @@helpers[id].each do |m|
        f.puts 
        xid = Source.find(m)
        Source.print_source(f, xid)
      end     
    end
  rescue Exception => e
    puts e
  end
  puts "Saved a copy of source in #{newfilename}"
  return true
end

.clear(name = nil) ⇒ Object

Remove all the probes on a designated method, or if no method name is passed, remove all probes from all methods.

:call-seq:

Source.clear(name)



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# File 'lib/rubylabs.rb', line 607

def Source.clear(name = nil)
  @@probes.each do |id, plist|
    next if ! name.nil? && id != name
    plist.clear
  end
  return true
end

.find(name) ⇒ Object

Internal use only – locate the filename, starting line number, and length of method name, record the information for any methods that need it. This information only needs to be found once, so it is recorded in a set of class variables. Revisit this decision if monitoring user-defined methods.…



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# File 'lib/rubylabs.rb', line 621

def Source.find(name)   # :nodoc:
  id = name.to_sym
  return id if @@file[id]     # return if we looked for this source previously
  
  filename, base, size, helpers = nil, nil, nil, nil
  
  catch (:found) do
    SCRIPT_LINES__.each do |file, lines|
      line_num = 0
      lines.each do |s|
        line_num += 1
        if match = s.match(/:(begin|end)\s+(.*)/)
          verb = match[1]
          names = match[2].split.collect{|x| eval(x)}
          if names[0] == id
            if verb == "begin"
              filename = file
              base = line_num + 1
              helpers = names[1..-1]
            else
              size = line_num - base
              throw :found
            end
          end
        end
      end
    end
  end
  
  raise "Can't find method named '#{name}'" if size.nil?

  @@file[id] = filename
  @@size[id] = size
  @@base[id] = base
  @@probes[id] = Hash.new
  @@helpers[id] = helpers
  return id      
end

.info(name) ⇒ Object

Internal use only – show info about method to verify it’s being found by Source.lines



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# File 'lib/rubylabs.rb', line 694

def Source.info(name)   # :nodoc:
  unless id = Source.find(name)
    puts "Can't find method named '#{name}'"
    return
  end

  printf "file:     %s\n", @@file[id]
  printf "size:     %d\n", @@size[id]
  printf "base:     %d\n", @@base[id]
  printf "helpers:  %s\n", @@helpers[id].inspect
  printf "probes:   %s\n", @@probes[id].inspect
end

.lines(spec, id) ⇒ Object

Internal use only – make an array of line numbers to use for probing method name. Argument can be a single line number, an array of line numbers, or a pattern. Checks to make sure line numbers are valid.



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# File 'lib/rubylabs.rb', line 664

def Source.lines(spec, id)    # :nodoc:
  if spec.class == Fixnum && Source.range_check(spec, id)
    return [spec]
  elsif spec.class == Array
    res = Array.new
    spec.each do |line|
      raise "line number must be an integer" unless line.class == Fixnum
      res << line if Source.range_check(line, id)
    end
    return res
  elsif spec.class == String
    res = Array.new
    for i in @@base[id]..(@@base[id]+@@size[id]-1)
      line = SCRIPT_LINES__[@@file[id]][i-1].chomp
      res << i - @@base[id] + 1 if line.index(spec)
    end
    return res
  else
    raise "invalid spec: '#{spec}' (must be an integer, array of integers, or a pattern)"
  end    
end

.listing(name) ⇒ Object

Print a listing (source code along with line numbers) for method name.

:call-seq:

Source.listing(name)



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# File 'lib/rubylabs.rb', line 458

def Source.listing(name)
  begin
    id = Source.find(name)
    for i in @@base[id]..(@@base[id]+@@size[id]-1)
      line = SCRIPT_LINES__[@@file[id]][i-1].chomp
      printf "%3d:  %s\n", i - @@base[id] + 1, line.gsub(/\t/,"  ")
    end
  rescue Exception => e
    puts e
  end
  return true
end

.print_source(f, id) ⇒ Object

Helper method called from Source.checkout – print the code for method id in the file f



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# File 'lib/rubylabs.rb', line 524

def Source.print_source(f, id)    # :nodoc:
  for i in @@base[id]..(@@base[id]+@@size[id]-1)
    line = SCRIPT_LINES__[@@file[id]][i-1].chomp
    f.puts line.gsub(/\t/,"  ")
  end      
end

.probe(name, spec, expr = :count) ⇒ Object 



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# File 'lib/rubylabs.rb', line 559

def Source.probe(name, spec, expr = :count)
  begin
    id = Source.find(name)
    Source.lines(spec, id).each do |n|
      n += @@base[id] - 1
      @@probes[id][n] = expr
    end
  rescue Exception => e
    puts e
  end
  return true
end

.probes ⇒ Object

Print a description of all the currently defined probes.

:call-seq:

Source.probes()



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# File 'lib/rubylabs.rb', line 590

def Source.probes
  @@probes.each do |name, plist|
    plist.each do |line, exprs|
      n = line - @@base[name] + 1
      printf "%s %2d: %s\n", name, n, exprs
    end
  end
  return true
end

.probing(filename, method, line) ⇒ Object

– Method for internal use only –

Return probes (if any) attached to the specified file, method, and line number. Intended to be called from a trace func callback (which is why the file is one of the parameters).



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# File 'lib/rubylabs.rb', line 577

def Source.probing(filename, method, line)  # :nodoc:
  return nil if line == @@line
  @@line = line
  return nil unless @@probes[method] && @@file[method] == filename
  return @@probes[method][line] 
end

.range_check(n, id) ⇒ Object

:nodoc:



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# File 'lib/rubylabs.rb', line 686

def Source.range_check(n, id)   # :nodoc:
  max = @@size[id]
  raise "line number must be between 1 and #{max}" unless n >= 1 && n <= max
  return true
end