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########################################################################
##
## Copyright (C) 2009-2022 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING. If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################
## -*- texinfo -*-
## @deftypefn {} {} print_usage ()
## @deftypefnx {} {} print_usage (@var{name})
## Print the usage message for the function @var{name}.
##
## When called with no input arguments the @code{print_usage} function displays
## the usage message of the currently executing function.
## @seealso{help}
## @end deftypefn
function print_usage (name)
x = dbstack ();
## Handle input
if (nargin == 0)
## Determine the name of the calling function
if (numel (x) > 1)
name = x(2).name;
else
error ("Octave:invalid-context", "print_usage: invalid function\n");
endif
fullname = evalin ("caller", 'mfilename ("fullpath")');
if (strcmp (fullname(end-length (name)+1:end), name))
fullname = [fullname ".m"];
endif
elseif (! ischar (name))
error ("Octave:invalid-input-arg",
"print_usage: input argument must be a string");
else
fullname = name;
endif
## Determine if we were called from top level.
at_toplev = length (x) < 2 || (length (x) == 2 && strcmp (x(2).name, name));
## Do the actual work
[text, format] = get_help_text (fullname);
max_len = 80;
switch (lower (format))
case "plain text"
[usage_string, status] = get_usage_plain_text (text, max_len);
case "texinfo"
[usage_string, status] = get_usage_texinfo (text, max_len);
case "html"
[usage_string, status] = get_usage_html (text, max_len);
case "not documented"
error ("print_usage: '%s' is not documented\n", name);
case "not found"
error ("print_usage: '%s' not found\n", name);
otherwise
error ("print_usage: internal error: unsupported help text format: '%s'\n", format);
endswitch
## Raise the final error
if (status != 0)
warning ("print_usage: Texinfo formatting filter exited abnormally");
warning ("print_usage: raw Texinfo source of help text follows...\n");
endif
## We don't want to start the debugger here if debug_on_error is true
## so we set it to false and make the change local. Then
## debug_on_error will be reset to true after this function returns
## and the debugger will start at the location of the call to
## print_usage.
debug_on_error (false, "local");
if (at_toplev)
error ("Octave:invalid-fun-call",
"Invalid call to %s. Correct usage is:\n\n%s\n%s",
name, usage_string, __additional_help_message__ ());
else
msg = sprintf ("Invalid call to %s. Correct usage is:\n\n%s",
name, usage_string);
## Ensure that the error doesn't end up with a newline, as that disables
## backtraces.
if (msg(end) == "\n")
msg(end) = " ";
endif
error ("Octave:invalid-fun-call", msg);
endif
endfunction
function [retval, status] = get_usage_plain_text (help_text, max_len)
## Extract first line by searching for a double line-end.
line_end_idx = strfind (help_text, "\n\n");
retval = help_text (1:min ([line_end_idx , max_len, length(help_text)]));
status = 0;
endfunction
function [retval, status] = get_usage_texinfo (help_text, max_len)
## Lines ending with "@\n" are continuation lines, so they should be
## concatenated with the following line.
help_text = strrep (help_text, "@\n", " ");
## Find, and keep, lines that start with @def or @end def. This should
## include things such as @deftypefn, @deftypefnx, @defvar, etc. and their
## corresponding @end's.
def_idx = strfind (help_text, "@def");
if (isempty (def_idx))
[retval, status] = get_usage_plain_text (help_text, max_len);
return;
endif
endf_idx = strfind (help_text, "@end def");
def_idx = sort ([def_idx, endf_idx]);
endl_idx = find (help_text == "\n");
buffer = "";
for k = 1:length (def_idx)
endl = endl_idx(find (endl_idx > def_idx(k), 1));
if (isempty (endl))
buffer = [buffer, help_text(def_idx(k):end), "\n"];
else
buffer = [buffer, help_text(def_idx(k):endl)];
endif
endfor
## Run makeinfo to generate plain text
[retval, status] = __makeinfo__ (buffer, "plain text");
endfunction
function [retval, status] = get_usage_html (help_text, max_len)
## Strip tags
[help_text, status] = strip_html_tags (help_text);
## Extract first line with plain text method.
retval = get_usage_plain_text (help_text, max_len);
endfunction
## Stop reporting function as missing tests. No good tests possible.
%!assert (1)
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