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-- Command Line OPTionS handler
-- ============================
--
-- This lib generates parsers for command-line options. It encourages
-- the following of some common idioms: I'm pissed off by Unix tools
-- which sometimes will let you concatenate single letters options,
-- sometimes won't, will prefix long name options with simple dashes
-- instead of doubles, etc.
--
--------------------------------------------------------------------------------
-- TODO:
-- * add a generic way to unparse options ('grab everything')
-- * doc
-- * when a short options that takes a param isn't the last element of a series
-- of shorts, take the remaining of the sequence as that param, e.g. -Ifoo
-- * let unset strings/numbers with +
-- * add a ++ long counterpart to +
--
-{ extension 'match' }
function clopts(cfg)
local short, long, param_func = { }, { }
local legal_types = table.transpose{
'boolean','string','number','string*','number*','nil', '*' }
-----------------------------------------------------------------------------
-- Fill short and long name indexes, and check its validity
-----------------------------------------------------------------------------
for x in ivalues(cfg) do
local xtype = type(x)
if xtype=='table' then
if not x.type then x.type='nil' end
if not legal_types[x.type] then error ("Invalid type name "..x.type) end
if x.short then
if short[x.short] then error ("multiple definitions for option "..x.short)
else short[x.short] = x end
end
if x.long then
if long[x.long] then error ("multiple definitions for option "..x.long)
else long[x.long] = x end
end
elseif xtype=='function' then
if param_func then error "multiple parameters handler in clopts"
else param_func=x end
end
end
-----------------------------------------------------------------------------
-- Print a help message, summarizing how to use the command line
-----------------------------------------------------------------------------
local function print_usage(msg)
if msg then print(msg,'\n') end
print(cfg.usage or "Options:\n")
for x in values(cfg) do
if type(x) == 'table' then
local opts = { }
if x.type=='boolean' then
if x.short then opts = { '-'..x.short..'/+'..x.short } end
if x.long then table.insert (opts, '--'..x.long..'/++'..x.long) end
else
if x.short then opts = { '-'..x.short..' <'..x.type..'>' } end
if x.long then table.insert (opts, '--'..x.long..' <'..x.type..'>' ) end
end
printf(" %s: %s", table.concat(opts,', '), x.usage or '<undocumented>')
end
end
print''
end
-- Unless overridden, -h and --help display the help msg
local default_help = { action = | | print_usage() or os.exit(0);
long='help';short='h';type='nil'}
if not short.h then short.h = default_help end
if not long.help then long.help = default_help end
-----------------------------------------------------------------------------
-- Helper function for options parsing. Execute the attached action and/or
-- register the config in cfg.
--
-- * cfg is the table which registers the options
-- * dict the name->config entry hash table that describes options
-- * flag is the prefix '-', '--' or '+'
-- * opt is the option name
-- * i the current index in the arguments list
-- * args is the arguments list
-----------------------------------------------------------------------------
local function actionate(cfg, dict, flag, opt, i, args)
local entry = dict[opt]
if not entry then print_usage ("invalid option "..flag..opt); return false; end
local etype, name = entry.type, entry.name or entry.long or entry.short
match etype with
| 'string' | 'number' | 'string*' | 'number*' ->
if flag=='+' or flag=='++' then
print_usage ("flag "..flag.." is reserved for boolean options, not for "..opt)
return false
end
local arg = args[i+1]
if not arg then
print_usage ("missing parameter for option "..flag..opt)
return false
end
if etype:strmatch '^number' then
arg = tonumber(arg)
if not arg then
print_usage ("option "..flag..opt.." expects a number argument")
end
end
if etype:strmatch '%*$' then
if not cfg[name] then cfg[name]={ } end
table.insert(cfg[name], arg)
else cfg[name] = arg end
if entry.action then entry.action(arg) end
return i+2
| 'boolean' ->
local arg = flag=='-' or flag=='--'
cfg[name] = arg
if entry.action then entry.action(arg) end
return i+1
| 'nil' ->
cfg[name] = true;
if entry.action then entry.action() end
return i+1
| '*' ->
local arg = table.isub(args, i+1, #args)
cfg[name] = arg
if entry.action then entry.action(arg) end
return #args+1
| _ -> assert( false, 'undetected bad type for clopts action')
end
end
-----------------------------------------------------------------------------
-- Parse a list of commands: the resulting function
-----------------------------------------------------------------------------
local function parse(...)
local cfg = { }
if not ... then return cfg end
local args = type(...)=='table' and ... or {...}
local i, i_max = 1, #args
while i <= i_max do
local arg, flag, opt, opts = args[i]
--printf('beginning of loop: i=%i/%i, arg=%q', i, i_max, arg)
if arg=='-' then
i=actionate (cfg, short, '-', '', i, args)
-{ `Goto 'continue' }
end
-----------------------------------------------------------------------
-- double dash option
-----------------------------------------------------------------------
flag, opt = arg:strmatch "^(%-%-)(.*)"
if opt then
i=actionate (cfg, long, flag, opt, i, args)
-{ `Goto 'continue' }
end
-----------------------------------------------------------------------
-- double plus option
-----------------------------------------------------------------------
flag, opt = arg:strmatch "^(%+%+)(.*)"
if opt then
i=actionate (cfg, long, flag, opt, i, args)
-{ `Goto 'continue' }
end
-----------------------------------------------------------------------
-- single plus or single dash series of short options
-----------------------------------------------------------------------
flag, opts = arg:strmatch "^([+-])(.+)"
if opts then
local j_max, i2 = opts:len()
for j = 1, j_max do
opt = opts:sub(j,j)
--printf ('parsing short opt %q', opt)
i2 = actionate (cfg, short, flag, opt, i, args)
if i2 ~= i+1 and j < j_max then
error ('short option '..opt..' needs a param of type '..short[opt])
end
end
i=i2
-{ `Goto 'continue' }
end
-----------------------------------------------------------------------
-- handler for non-option parameter
-----------------------------------------------------------------------
if param_func then param_func(args[i]) end
if cfg.params then table.insert(cfg.params, args[i])
else cfg.params = { args[i] } end
i=i+1
-{ `Label 'continue' }
if not i then return false end
end -- </while>
return cfg
end
return parse
end