--- name: "UI::Dialog::Backend" section: "3pm" platform: "linux" package: "libui-dialog-perl" version: "1.21-0.1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/UI::Dialog::Backend" --- # UI::Dialog::Backend(3pm) simply a collection of primarily internal methods. ## NAME UI::Dialog::Backend - simply a collection of primarily internal methods. ## SYNOPSIS ``` use UI::Dialog::Backend; BEGIN { use vars qw( @ISA ); @ISA = qw( UI::Dialog::Backend ); } ``` ## ABSTRACT UI::Dialog::Backend is simply a collection of primarily internal methods. ## DESCRIPTION While this module is inherited by all UI::Dialog backend modules, this module itself is not meant for direct usage. The "STATE METHODS" and "UTILITY METHODS" documentation is applicable to all backends thus rendering the POD for this class more important to the end-programmer than the usage of the class itself. ## EXPORT None ## INHERITS None ## BACKEND EXTENSIONS ### nautilus - EXAMPLE ``` my @paths = $d->nautilus->paths(); ``` - DESCRIPTION This method gives access to the UI::Dialog::Backend::Nautilus class. This will automagically try to load the UI::Dialog::Backend::Nautilus module or it will silently fail. ### xosd - EXAMPLE ``` $d->xosd->line( "a line of text on your screen" ); ``` - DESCRIPTION This method gives access to the UI::Dialog::Backend::XOSD class. This will automagically try to load the UI::Dialog::Backend::XOSD module or it will silently fail. ### notify\_send - EXAMPLE ``` $d->notify_send->notify_send( "a line of text on your screen" ); ``` - DESCRIPTION This method gives access to the UI::Dialog::Backend::NotifySend class. This will automagically try to load the UI::Dialog::Backend::NotifySend module or it will silently fail. ## STATE METHODS ### attr( ) - EXAMPLE ``` my $value = $self->attr('listheight'); my $new_value = $d->attr('listheight',5); ``` - DESCRIPTION Either sets and returns the value of the desired attribute, or just returns the value of the desired attribute. - RETURNS a single SCALAR. ### state( ) - EXAMPLE ``` if ($d->state() eq "OK") { # the last user response was "OK" } else { # something other than an "OK" response } ``` - DESCRIPTION Returns the state of the last dialog widget command. The value can be one of "OK", "CANCEL" or "ESC". The return data is based on the exit codes (return value) of the last widget displayed. Some backends also support other exit values than the standard few and these are represented as "EXTRA" (3), "HELP" (2), and "ERROR" (255). - RETURNS a single SCALAR. ### ra( ) - EXAMPLE ``` my @array = $d->ra(); ``` - DESCRIPTION Returns the last widget's data as an array. - RETURNS an ARRAY. ### rs( ) - EXAMPLE ``` my $string = $d->rs(); ``` - DESCRIPTION Returns the last widget's data as a (possibly multiline) string. - RETURNS a SCALAR. ### rv( ) - EXAMPLE ``` my $string = $d->rv(); ``` - DESCRIPTION Returns the last widget's exit status, aka: return value. This is the value used when determining the *state()* of a widget. - RETURNS a SCALAR. ## CALLBACK FUNCTIONS ### PRE - EXAMPLE ``` sub CB_PRE { my $widget_args = shift(); print "Caller: ".$args->{'caller'}."\n"; } my $d = new UI::Dialog ( callbacks => { PRE => \&CB_PRE } ); ``` - DESCRIPTION This function recieves a hasref of the current argument values and is called before any widget performs any operations. ### POST - EXAMPLE ``` sub CB_POST { my $widget_args = shift(); my $state = shift(); print "Caller: ".$args->{'caller'}.", State: ".$state."\n"; } my $d = new UI::Dialog ( callbacks => { POST => \&CB_POST } ); ``` - DESCRIPTION This function recieves a hasref of the current argument values and the one word state indicator (as reported by *state()*) and is called after all widget operations have been performed (including other callback functions). ### OK - EXAMPLE ``` sub CB_OK_FUNC { my $widget_args = shift(); print "Widget caller: ".$args->{'caller'}."\n"; } my $d = new UI::Dialog ( callbacks => { OK => \&CB_OK_FUNC } ); ``` - DESCRIPTION This function recieves a hasref of the current argument values and is called when any widget finishes with a *state()* of "OK" but before the POST callback. ### CANCEL - EXAMPLE ``` sub CB_CANCEL { my $widget_args = shift(); print "Caller: ".$args->{'caller'}."\n"; } my $d = new UI::Dialog ( callbacks => { CANCEL => \&CB_CANCEL } ); ``` - DESCRIPTION This function recieves a hasref of the current argument values and is called when any widget finishes with a *state()* of "CANCEL" but before the POST callback. Be forewarned that with respect to the *yesno()* type widgets, a user response of "NO" is interpreted as "CANCEL" and will execute this function. ### ESC - EXAMPLE ``` sub CB_ESC { my $widget_args = shift(); print "Caller: ".$args->{'caller'}."\n"; } my $d = new UI::Dialog ( callbacks => { ESC => \&CB_ESC } ); ``` - DESCRIPTION This function recieves a hasref of the current argument values and is called when any widget finishes with a *state()* of "ESC" but before the POST callback. ### HELP - EXAMPLE ``` sub CB_HELP { my $widget_args = shift(); print "Caller: ".$args->{'caller'}."\n"; } my $d = new UI::Dialog ( callbacks => { HELP => \&CB_HELP } ); ``` - DESCRIPTION This function recieves a hasref of the current argument values and is called when any widget finishes with a *state()* of "HELP" but before the POST callback. The user response of "HELP" is not supported by all backends. ### EXTRA - EXAMPLE ``` sub CB_EXTRA { my $widget_args = shift(); print "Caller: ".$args->{'caller'}."\n"; } my $d = new UI::Dialog ( callbacks => { EXTRA => \&CB_EXTRA } ); ``` - DESCRIPTION This function recieves a hasref of the current argument values and is called when any widget finishes with a *state()* of "EXTRA" but before the POST callback. The user response of "EXTRA" is not supported by all backends. ## UTILITY METHODS ### beep( ) - EXAMPLE ``` $d->beep(); ``` - DESCRIPTION If the [*beep*(1)](/beep/1.md) application can be found, use it to make a beep sound. Otherwise print "\\a" to STDERR which normally is good enough to make some noise. - RETURNS TRUE (1) regardless of result. ### clear( ) - EXAMPLE ``` $d->clear(); ``` - DESCRIPTION Clear the terminal screen via STDOUT and the \`clear\` command. This method is technically useless for any GUI based dialog variants. - RETURNS TRUE (1) regardless of result. ### word\_wrap( ) - EXAMPLE ``` my @wrapped_text = $d->word_wrap($cols,$indent,$sub_indent,@text); ``` - DESCRIPTION Using the Text::Wrap::wrap function, wrap the words in a string (or array of strings). This is primarily used within the *\_organize\_text()* method but may be of use to the end-programmer. - RETURNS A word-wrapped version of the given text data. ### gen\_tempfile\_name( ) - EXAMPLE ``` my $tempfile = $d->gen_tempfile_name(); ``` - DESCRIPTION This method returns a temporary file name generated using one of the following (in order): the File::Temp perl module if detected, the program "mktemp" or an extremely simplistic built-in name generator. - RETURNS A temporary file name. ### gen\_random\_string( ) - EXAMPLE ``` my $random_string = $d->gen_random_string(5); ``` - DESCRIPTION This will return a string of random (printable) characters of an arbitrary user-definable length (defaults to 5); - RETURNS A string of random ASCII characters. ## WIDGET WRAPPER METHODS These methods are common methods to most backends as they do not have native support for the functionality, yet the functionality is achievable by utilizing existing compatible methods. ### fselect( ) - EXAMPLE ``` my $path = $self->fselect( path => $start_path ); ``` - DESCRIPTION Using the *menu()* and *msgbox()* widgets we can simulate a file browser interface. Note: to select a directory, go into it and then pick the '.' entry. - RETURNS a SCALAR for positive results and FALSE (0) for everything else. ### dselect( ) - EXAMPLE ``` my $path = $self->dselect( path => $start_path ); ``` - DESCRIPTION Using the *fselect()* widget we can simulate a directory browser interface. Note: to select a directory, go into it and then pick the '.' entry. - RETURNS a SCALAR for positive results and FALSE (0) for everything else. ## BACKEND METHODS These methods are only necessary for someone wishing to create more UI::Dialog::Backend:: Modules. These are never needed to be directly used but are none the less documented here for reference purposes. ### command\_state( ) - EXAMPLE ``` if ($self->command_state("/some/shell/command")) { #: command succeeded } else { #: command failed } ``` - DESCRIPTION This will execute the given command and send STDOUT and STDERR to /dev/null then analyse the exit code and return accordingly. - RETURNS TRUE (1) for positive results and FALSE (0) for anything else. ### command\_string( ) - EXAMPLE ``` my ($rv,$scalar) = $self->command_string("/some/shell/command"); if ($rv >= 1) { #: command failed } else { #: command succeeded print "The command results: ".$scalar."\n"; } ``` - DESCRIPTION This will execute the given command, catch STDOUT and STDERR, then return the SCALAR data. - RETURNS a SCALAR for positive results and FALSE (0) for anything else. ### command\_array( ) - EXAMPLE ``` my ($rv,@array) = $self->command_array("/some/shell/command"); if ($rv >= 1) { #: command failed } else { #: command succeeded foreach my $line_of_output (@array) { print "The command results: ".$line_of_output."\n"; } } ``` - DESCRIPTION This will execute the given command, catch STDOUT and STDERR, then return the data, split by newlines, as an ARRAY. - RETURNS an ARRAY for positive results and FALSE (0) for anything else. ### \_pre( ) - EXAMPLE ``` my $args = $self->_pre(@_); ``` - DESCRIPTION This will use *\_merge\_attrs()*, perform any pre-widget-exec things and then return the current argument list as a hashref. This is used in every widget before anything is actually done in the widget and is responsible for running the optional callback function labelled "PRE". - RETURNS a HASHREF. ### \_post( ) - EXAMPLE ``` $self->_post( $args ); ``` - DESCRIPTION This method is used in every widget after all operations (for the immediate widget call) are complete but before the widget actually returns anything. This method is responsible for running the optional callback funcions labelled "OK", "ESC", "CANCEL" and "POST" with "POST" being executed absolutely last. - RETURNS Nothing. ### \_merge\_attrs( ) - EXAMPLE ``` my $args = $self->_merge_attrs(@_); ``` - DESCRIPTION This will apply the arguments passed in with the defaults stored in `$self`-\>{'\_opts'} (which was instantiated upon object construction). The return result is the "current" options as defined by the defaults with the argument options overriding them. - RETURNS a HASHREF. ### \_find\_bin( ) - EXAMPLE ``` my $ZenityBinaryPath = $self->_find_bin('zenity'); ``` - DESCRIPTION This will look in the default path directories for the program of the given name. The default PATH list is: /bin, /usr/bin, /usr/local/bin, /opt/bin. - RETURNS a SCALAR. ### \_esc\_text( ) - EXAMPLE ``` my $escaped_text = $self->_esc_text( $raw_text ); ``` - DESCRIPTION This will escape the following with a prefixing '\\' character: ``` Character -> Escaped " \" ` \` ( \( ) \) [ \[ ] \] { \} } \} $ \$ < \< > \> ``` - RETURNS an SCALAR for positive results and FALSE (0) for anything else. ### \_strip\_text( ) - EXAMPLE ``` my $clean_text = $self->_strip_text( $text_with_markup ); ``` - DESCRIPTION This will strip various markup sequences from within the given argument data. - RETURNS an SCALAR for positive results and FALSE (0) for anything else. ### \_organize\_text( ) - EXAMPLE ``` my $final_text1 = $self->_organize_text( $text_with_markup ); my $final_text2 = $self->_organize_text( \@text_with_markup ); ``` - DESCRIPTION This will strip various markup sequences from within the given argument data. - RETURNS a SCALAR for positive results and FALSE (0) for anything else. ### \_is\_bsd( ) - EXAMPLE ``` if ($self->_is_bsd()) { # do something with BSD specific characteristics } else { # do something with general perl characteristics } ``` - DESCRIPTION This simply checks (case-insensitively) the perlvar $^0 for the string "bsd". - RETURNS TRUE (1) for positive results and FALSE (0) for anything else. ### \_list\_dir( ) - EXAMPLE ``` my $menu_list = $self->_list_dir( '/some/path/to/a/directory', [ 'optional', 'prefix', 'items' ] ); ``` - DESCRIPTION Gather a list of the contents of a directory and forumlate a list suitable for use with most (if not all) file/path selection dialog variant widgets. An optional array reference will have all elements prefixing the directory list. - RETURNS an ARRAYREF for positive results and FALSE (0) for anything else. ### \_debug( ) - EXAMPLE ``` $self->_debug( $debuging_message_string, $debuging_level ); ``` - DESCRIPTION This method will print to STDERR the debugging message provided if and only if the debuging level is greater than or equal to the `$debuging_level`. The debugging level argument is optional and defaults to a level of 1. - RETURNS TRUE (1) for positive results and FALSE (0) for anything else. ### \_error( ) - EXAMPLE ``` $self->_error( $error_message_string ); ``` - DESCRIPTION This method will print to STDERR the error message provided regardless of debugging level. - RETURNS TRUE (1) for positive results and FALSE (0) for anything else. ## SEE ALSO - PERLDOC ``` UI::Dialog UI::Dialog::Console UI::Dialog::GNOME UI::Dialog::KDE UI::Dialog::Backend::ASCII UI::Dialog::Backend::CDialog UI::Dialog::Backend::GDialog UI::Dialog::Backend::KDialog UI::Dialog::Backend::Nautilus UI::Dialog::Backend::Whiptail UI::Dialog::Backend::XDialog UI::Dialog::Backend::XOSD UI::Dialog::Backend::Zenity ``` - MAN FILES ``` dialog(1), whiptail(1), zenity(1), gdialog(1), Xdialog(1), kdialog(1), nautilus(1) and osd_cat(1). ``` ## BUGS Please email the author with any bug reports. Include the name of the module in the subject line. ## AUTHOR Kevin C. Krinke, \ ## COPYRIGHT AND LICENSE ``` Copyright (C) 2004-2016 Kevin C. Krinke This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ```