Class: CommandLine

Inherits:
Object
  • Object
show all
Defined in:
lib/cmdline.rb

Constant Summary collapse

FLAG_1 = 
0
FLAG_2 = 
1
ACCESSOR = 
2
DISP_NAME = 
3
REQUIRED = 
4
DEFAULT = 
5
DOC = 
6
CHECK = 
7
@@add_help = 
true

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(definition) ⇒ CommandLine

definition

:command, nil, <accessor>, <display name>, <required?>, <default>, <doc>, <check allowed commands>

command is a subcommand, cf. ‘svn help`,

<flag1>, <flag2/nil>, <accessor>, <display name>, <required?>, <default>, <doc>, <check: optional>

commandline taking arguments, e.g. ‘mv src target` are specified like this:

:args, nil, <accessor>, <display name>, <required>, <default>, <doc>, <check: optional>

the entire rest of the commandline arg array after the first unrecognized options will then be available under ‘cmdline.<accessor>` the check proc will either be able to check the entire array or, if that fails with an exception, will test each element individually.



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# File 'lib/cmdline.rb', line 34

def initialize definition
  self.definition= definition
  @output_io ||= STDERR
  @exit_on_usage=true

end

Class Method Details

.add_help=(bool) ⇒ Object 



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# File 'lib/cmdline.rb', line 18

def self.add_help= bool
  @@add_help=bool
end

Instance Method Details

#definition=(definition) ⇒ Object 



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# File 'lib/cmdline.rb', line 53

def definition= definition
  definition.push(["-h", "--help", :help, false,  false, nil, "print this message"]) if @@add_help
  cl = class << self; self; end
  # add an accessor to self for each definition.
  cl.instance_eval { attr_accessor *definition.map{|arg_def| arg_def[ACCESSOR]} }
  

  definition.each {|arg_def|
    #check if cmdline takes a command
    if arg_def[FLAG_1]==:command
      @has_command = true
    end
    #set default values
    set arg_def[ACCESSOR], arg_def[DEFAULT]
  }

  @definition=definition

  class << @definition
    def retrieve_flag flag
      find { |arg|
        arg[FLAG_1]==flag || arg[FLAG_2]==flag
      }
    end
  end

end

#exit_on_usage=(bool) ⇒ Object

whether exit will be called to terminate the program if usage is called. Default behaviour is to call exit If this behaviour is turned off, a call to usage will result in an exception instead.



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# File 'lib/cmdline.rb', line 49

def exit_on_usage= bool
  @exit_on_usage= bool
end

#output=(io) ⇒ Object 



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# File 'lib/cmdline.rb', line 41

def output= io
  @output_io = io
end

#parse(args = ARGV) ⇒ Object 



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# File 'lib/cmdline.rb', line 145

def parse args=ARGV
  @found = []
  i=0
  # handle svn like command
  if definition = @definition.retrieve_flag(:command)

    if definition[REQUIRED] && args.length==0
      usage "missing mandatory command"
    elsif test_def = @definition.retrieve_flag(args[i])
      usage "missing mandatory command" if definition[REQUIRED] 
    else
    
      check definition, args[i]
      set definition[ACCESSOR], args[i]

      i+=1
    end 
      
  end

  while i<args.length do
    @found.push args[i]
    if definition = @definition.retrieve_flag(args[i]) # is there a definition for this flag?
      if definition[DISP_NAME]
        # takes a parameter
        check definition, args[i+=1]
        set definition[ACCESSOR], args[i] 
      else
        # plain flag
        set definition[ACCESSOR], true
      end  
    else  # are unknown flags ok? i.e. is there an :args definition.
      if definition = @definition.retrieve_flag(:args)
        check_args definition, args[i, args.length-1]
        set definition[ACCESSOR], args[i, args.length-1]
        break
      end
      usage "unknown flag: #{args[i]}"
    end
    i+=1
  end

  if definition = @definition.retrieve_flag(:args) # are :args required?
    if definition[REQUIRED]
      args = self.send definition[ACCESSOR]
      usage "missing mandatory args" unless args && args.length>1
    end
  end
  
  usage if self.help # call usage if the -h/--help flag was set.

  # check all mandatory args are present.
  @definition.each {|definition|

    if definition[REQUIRED] && !([:command, :args].include? definition[FLAG_1])
      usage "missing mandatory flag #{definition [FLAG_1]?definition[FLAG_1]:definition[FLAG_2]}" unless ((@found.include? definition[FLAG_1]) || (@found.include? definition[FLAG_2]))
    end
  }
end

#usage(mes = "") ⇒ Object

definition



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# File 'lib/cmdline.rb', line 81

def usage mes=""
  raise mes unless @exit_on_usage

  
  # put together usage information for flags.  
  max = 0      #max flag length for formatting
  has_required=false
  has_options=false
  us = @definition.map {|arg_def|
    if arg_def[FLAG_1] == :command 
      flag=:command
    elsif arg_def[FLAG_1] == :args
      flag=:args 
    else
  # create a usage string of the form:
  #   -f/-flag <value>* must start with a number
  # for each definition. (commands and args are treated seperately)    
      flag = "#{arg_def[FLAG_1]}"
      flag << "/#{arg_def[FLAG_2]}" if arg_def[FLAG_2]
      flag << " <#{arg_def[DISP_NAME]}>" if arg_def[DISP_NAME]
      flag << "*" if arg_def[REQUIRED]
      has_required = true if arg_def[REQUIRED]
      has_options = true
      max = max > flag.length ? max : flag.length
    end
    [flag, arg_def[DOC]]
  }
  
  usage = "usage: #{$0}"
  
  if command=@definition.retrieve_flag(:command)
    fmt = command[REQUIRED] ? " %s" : " [%s]"
    usage << sprintf(fmt,command[DISP_NAME])
  end
  
  if has_options
    usage << (has_required ? " options" : " [options]")
  end
  
  args_doc=false
  if command=@definition.retrieve_flag(:args)
    fmt = command[REQUIRED] ? " %s" : " [%s]"
    usage << sprintf(fmt,command[DISP_NAME])
    args_doc = "#{command[DISP_NAME]}: #{command[DOC]}"
  end
  usage << "\n"

  us.each { |arg_def|
    if arg_def[0].kind_of? String
      usage << sprintf("  %-#{max}s %s\n", arg_def[0], arg_def[1]) 
    elsif arg_def[0] == :command
      # command 
      usage << arg_def[1] if arg_def[1] 
    end

  }
  @output_io.puts usage
  @output_io.puts "* required flags" if has_required
  @output_io.puts "\n#{args_doc}" if args_doc
  @output_io.puts
  @output_io.puts mes
  exit 
end