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diff --git a/docs/pycon2010/pycon2010.rst b/docs/pycon2010/pycon2010.rst new file mode 100644 index 0000000..0b3b7a4 --- /dev/null +++ b/docs/pycon2010/pycon2010.rst @@ -0,0 +1,382 @@ +================================================ +Easy command-line interpreters with cmd and cmd2 +================================================ + +:author: Catherine Devlin +:date: 2010-02-20 +:slides: http://pypi.python.org/pypi/cmd2 + +Web 2.0 +======= + +.. image:: web-2-0-logos.gif + :height: 350px + +But first... +============ + +.. image:: sargon.jpg + :height: 250px + +.. image:: akkad.png + :height: 250px + +Sargon the Great + Founder of Akkadian Empire + +.. twenty-third century BC + +In between +========== + +.. image:: apple.jpg + :height: 250px + +Command-Line Interface + Unlike the Akkadian Empire, + the CLI will never die. + +Defining CLI +============ + +Also known as + +- "Line-oriented command interpreter" +- "Command-line interface" +- "Shell" + +1. Accepts free text input at prompt +2. Outputs lines of text +3. (repeat) + +Examples +======== + +.. class:: big + + * Bash, Korn, zsh + * Python shell + * screen + * Zork + * SQL clients: psql, SQL*\Plus, mysql... + * ed + +.. ``ed`` proves that CLI is sometimes the wrong answer. + +!= Command Line Utilities +========================= + +.. class:: big + + (``ls``, ``grep``, ``ping``, etc.) + + 1. Accept arguments at invocation + 2. execute + 3. terminate + + Use ``sys.argv``, ``optparse`` + +!="Text User Interface" +======================= + +* Use entire (session) screen +* I/O is *not* line-by-line +* See ``curses``, ``urwid`` + +.. image:: urwid.png + :height: 250px + + +Decide your priorities +====================== + +.. image:: strategy.png + :height: 350px + +A ``cmd`` app: pirate.py +======================== + +:: + + from cmd import Cmd + + class Pirate(Cmd): + pass + + pirate = Pirate() + pirate.cmdloop() + +.. Nothing here... but history and help + +.. ctrl-r for bash-style history + +Fundamental prrrinciple +======================= + +.. class:: huge + + ``(Cmd) foo a b c`` + + becomes + + ``self.do_foo('a b c')`` + +``do_``-methods: pirate2.py +=========================== + +:: + + class Pirate(Cmd): + gold = 3 + def do_loot(self, arg): + 'Seize booty frrrom a passing ship.' + self.gold += 1 + print('Now we gots {0} doubloons' + .format(self.gold)) + def do_drink(self, arg): + 'Drown your sorrrows in rrrum.' + self.gold -= 1 + print('Now we gots {0} doubloons' + .format(self.gold)) + +.. do_methods; more help + +Hooks +===== + +.. image:: hook.jpg + :height: 250px + +:: + + self.preloop() + self.postloop() + self.precmd(line) + self.postcmd(stop, line) + +Hooks: pirate3.py +================= + +:: + + def do_loot(self, arg): + 'Seize booty from a passing ship.' + self.gold += 1 + def do_drink(self, arg): + 'Drown your sorrrows in rrrum.' + self.gold -= 1 + def precmd(self, line): + self.initial_gold = self.gold + return line + def postcmd(self, stop, line): + if self.gold != self.initial_gold: + print('Now we gots {0} doubloons' + .format(self.gold)) + +Arguments: pirate4.py +===================== + +:: + + def do_drink(self, arg): + '''Drown your sorrrows in rrrum. + + drink [n] - drink [n] barrel[s] o' rum.''' + try: + self.gold -= int(arg) + except: + if arg: + print('''What's "{0}"? I'll take rrrum.''' + .format(arg)) + self.gold -= 1 + +quitting: pirate5.py +==================== + +:: + + def postcmd(self, stop, line): + if self.gold != self.initial_gold: + print('Now we gots {0} doubloons' + .format(self.gold)) + if self.gold < 0: + print("Off to debtorrr's prison.") + stop = True + return stop + def do_quit(self, arg): + print("Quiterrr!") + return True + +prompts, defaults: pirate6.py +============================= + +:: + + prompt = 'arrr> ' + def default(self, line): + print('What mean ye by "{0}"?' + .format(line)) + +Other CLI packages +================== + +.. class:: big + + * CmdLoop + * cly + * CMdO + * pycopia + * cmdlin + * cmd2 + +Demo +==== + +.. class:: huge + + Convert ``cmd`` app to ``cmd2`` + +cmd2 +==== + +.. image:: schematic.png + :height: 350px + +As you wish, Guido +================== + +.. class:: huge + + Python 3 compatible + +(um, mostly) + +Absolutely free +=============== + +Script files + +Commands at invocation + +Output redirection + +Python + +Transcript testing + +But wait, there's more +====================== + + * Abbreviated commands + * Shell commands + * Quitting + * Timing + * Echo + * Debug + +Minor changes: pirate7.py +========================= + +:: + + default_to_shell = True + multilineCommands = ['sing'] + terminators = Cmd.terminators + ['...'] + songcolor = 'blue' + settable = Cmd.settable + 'songcolor Color to ``sing`` in (red/blue/green/cyan/magenta, bold, underline)' + Cmd.shortcuts.update({'~': 'sing'}) + def do_sing(self, arg): + print(self.colorize(arg, self.songcolor)) + +Now how much would you pay? +=========================== + +options / flags + +Quiet (suppress feedback) + +BASH-style ``select`` + +Parsing: terminators, suffixes + +Options: pirate8.py +=================== + +:: + + @options([make_option('--ho', type='int', default=2, + help="How often to chant 'ho'"), + make_option('-c', '--commas', + action="store_true", + help="Intersperse commas")]) + def do_yo(self, arg, opts): + chant = ['yo'] + ['ho'] * opts.ho + separator = ', ' if opts.commas else ' ' + chant = separator.join(chant) + print('{0} and a bottle of {1}' + .format(chant, arg)) + +Serious example: sqlpython +========================== + +.. class:: big + + ``cmd``-based app by Luca Canali @ CERN + + Replacement for Oracle SQL\*Plus + + Now ``cmd2``-based; postgreSQL; MySQL + +File reporter +============= + +.. class:: huge + + Gather info: Python + + Store: postgresql + + Report: html + +fileutil.py +=========== + +:: + + import glob + import os.path + + for fullfilename in glob.glob('/home/cat/proj/cmd2/*.py'): + (dirpath, fname) = os.path.split(fullfilename) + stats = os.stat(fullfilename) + binds['path'] = dirpath + binds['name'] = fname + binds['bytes'] = stats.st_size + cmd("""INSERT INTO cat.files (path, name, bytes) + VALUES (%(path)s, %(name)s, %(bytes)s)""") + quit() + +sqlpython features +================== + +.. class:: big + + * from ``cmd2``: scripts, redirection, + py, etc. + * multiple connections + * UNIX: ls, cat, grep + * Special output + + +Thank you +========= + +.. class:: big + + http://pypi.python.org/pypi/cmd2 + + http://catherinedevlin.blogspot.com + + http://catherinedevlin.pythoneers.com + + |