diff options
| -rw-r--r-- | Lib/cmd.py | 101 |
1 files changed, 84 insertions, 17 deletions
@@ -1,4 +1,39 @@ # A generic class to build line-oriented command interpreters +# +# Interpreters constructed with this class obey the following conventions: +# +# 1. End of file on input is processed as the command 'EOF'. +# 2. A command is parsed out of each line by collecting the prefix composed +# of characters in the identchars member. +# 3. A command `foo' is dispatched to a method 'do_foo()'; the do_ method +# is passed a single argument consisting of the remainder of the line. +# 4. Typing an empty line repeats the last command. (Actually, it calls the +# method `emptyline', which may be overridden in a subclass.) +# 5. There is a predefined `help' method. Given an argument `topic', it +# calls the command `help_topic'. With no arguments, it lists all topics +# with defined help_ functions, broken into up to three topics; documented +# commands, miscellaneous help topics, and undocumented commands. +# 6. The command '?' is a synonym for `help'. The command '!' is a synonym +# for `shell', if a do_shell method exists. +# +# The `default' method may be overridden to intercept commands for which there +# is no do_ method. +# +# The data member `self.ruler' sets the character used to draw separator lines +# in the help messages. If empty, no ruler line is drawn. It defaults to "=". +# +# If the value of `self.intro' is nonempty when the cmdloop method is called, +# it is printed out on interpreter startup. This value may be overridden +# via an optional argument to the cmdloop() method. +# +# The data members `self.doc_header', `self.misc_header', and +# `self.undoc_header' set the headers used for the help function's +# listings of documented functions, miscellaneous topics, and undocumented +# functions respectively. +# +# These interpreters use raw_input; thus, if the readline module is loaded, +# they automatically support Emacs-like command history and editing features. +# import string import sys @@ -8,27 +43,58 @@ PROMPT = '(Cmd) ' IDENTCHARS = string.letters + string.digits + '_' class Cmd: + prompt = PROMPT + identchars = IDENTCHARS + ruler = '=' + lastcmd = '' + intro = None + doc_header = "Documented commands (type help <topic>):" + misc_header = "Miscellaneous help topics:" + undoc_header = "Undocumented commands:" - def __init__(self): - self.prompt = PROMPT - self.identchars = IDENTCHARS - self.lastcmd = '' - - def cmdloop(self): + def cmdloop(self, intro=None): + self.preloop() + if intro != None: + self.intro = intro + if self.intro: + print self.intro stop = None while not stop: try: line = raw_input(self.prompt) except EOFError: line = 'EOF' + self.precmd() stop = self.onecmd(line) + self.postcmd() + self.postloop() + + def precmd(self): + pass + + def postcmd(self): + pass + + def preloop(self): + pass + + def postloop(self): + pass def onecmd(self, line): line = string.strip(line) - if not line: - line = self.lastcmd - else: - self.lastcmd = line + if line == '?': + line = 'help' + elif line == '!': + if hasattr(self, 'do_shell'): + line = 'shell' + else: + self.default(line) + return + elif not line: + self.emptyline() + return + self.lastcmd = line i, n = 0, len(line) while i < n and line[i] in self.identchars: i = i+1 cmd, arg = line[:i], string.strip(line[i:]) @@ -41,6 +107,9 @@ class Cmd: return self.default(line) return func(arg) + def emptyline(self): + return self.onecmd(self.lastcmd) + def default(self, line): print '*** Unknown syntax:', line @@ -70,17 +139,15 @@ class Cmd: else: cmds_undoc.append(cmd) print - self.print_topics("Documented commands (type help " \ - "<topic>):",cmds_doc, 15, 80) - self.print_topics("Miscellaneous help topics:", - help.keys(), 15, 80) - self.print_topics("Undocumented commands:", - cmds_undoc, 15, 80) + self.print_topics(self.doc_header, cmds_doc, 15,80) + self.print_topics(self.misc_header, help.keys(),15,80) + self.print_topics(self.undoc_header, cmds_undoc, 15,80) def print_topics(self, header, cmds, cmdlen, maxcol): if cmds: print header; - print "="*len(header) + if self.ruler: + print self.ruler * len(header) (cmds_per_line,junk)=divmod(maxcol,cmdlen) col=cmds_per_line for cmd in cmds: |