C Library Functions - M_attr (3)

NAME

M_attr(3f) - [M_attr::INTRO] control text attributes on terminals (LICENSE:MIT)

Synopsis
Description
Access
Limitations
Example
Author
License
See Also

SYNOPSIS

use M_attr, only : attr, attr_mode, attr_update
use M_attr, only : alert ! generate standard messages

DESCRIPTION

M_attr(3f) is a Fortran module that uses common ANSI escape sequences to control terminal text attributes.
        use M_attr
        write(*,*)attr(’<red>Red Text!</red> <green>Green Text!</green>’)
        end
It is designed to use three simple procedures to
    + Specify attributes using simple HTML-like syntax
    + allow the sequences to be suppressed when desired
    + permit the  user program to completely customize the keywords.
      The user can add, delete and replace the sequences associated with
      a keyword without changing the code.
One advantage of the approach of using formatting directives which are replaced with in-band escape sequences is that it is easy to turn off when running batch.
Another important capability is that programs can be run in "raw" mode and create a simple text file with the formatting directives in it that can then be read back in by a simple filter program that strips it back to plain text( see app/plain.f90), or displays it to a screen in color(see app/light.f90) or perhaps converts it to another format.
So this approach makes it trivial to read specially-formatted data from a file like a message catalog (perhaps with various versions in different languages) and colorize it or display it as plain text
By making each line self-contained (by default) lines can be filtered by external utilities and still display correctly.

ACCESS

Via git(1):

git clone https://github.com/urbanjost/M_attr.git cd M_attr/src # change Makefile if not using one of the listed compilers make clean; make gfortran # for gfortran make clean; make ifort # for ifort make clean; make nvfortran # for nvfortran

This will compile the M_attr module and example programs.

Alternatively, via fpm (see https://github.com/fortran-lang/fpm):

git clone https://github.com/urbanjost/M_attr.git

or just list it as a dependency in your fpm.toml project file.

        [dependencies]
        M_attr = { git = "https://github.com/urbanjost/M_attr.git" }

LIMITATIONS

o colors are not nestable.

o keywords are case-sensitive,

o ANSI escape sequences are not universally supported by all terminal emulators; and normally should be suppressed when not going to a tty device. Therefore, you should use M_system::system_istty(3f) or the common Fortran extension ISATTY() to set the default to "plain" instead of "color" when the output file is not a conforming terminal. On basic MSWindows console windows, it is best to use Windows 10+ and/or the Linux mode; you may have to enable ANSI escape sequence mode on MSWindows. It does work as-is with CygWin and MinGW and Putty windows and mintty(1) as tested.

EXAMPLE

Sample program

    program demo_M_attr
    use M_attr, only : attr, attr_mode, attr_update, alert
    implicit none
    character(len=256) :: line
    character(len=*),parameter :: f=’( &
     &"   <bo><w><G> GREAT: </G></w>&
     &The new value <Y><b>",f8.4,1x,"</b></Y> is in range"&
     &)’
    real :: value

       write(*,’(a)’)&
       &attr(’   <r><W><bo> ERROR: </W>red text on a white background</y>’)

       value=3.4567
       write(line,fmt=f) value
       write(*,’(a)’)attr(trim(line))

       ! write same string as plain text
       write(*,*)
       call attr_mode(manner=’plain’)
       write(*,’(a)’)attr(trim(line))

       call attr_mode(manner=’color’)
       ! use pre-defined or user defined strings
       write(*,*)
       write(*,’(a)’)attr(’<ERROR> Woe is nigh.’)
       write(*,’(a)’)attr(’<WARNING> The night is young.’)
       write(*,’(a)’)attr(’<INFO> It is Monday’)

       call alert(’<ERROR>’, ’Woe is nigh.’)
       call alert(’<WARNING>’, ’The night is young.’)
       call alert(’<INFO>’, ’It is Monday’)

       ! create a custom mnemonic
       call attr_update(’MYERROR’,attr(&
       ’ <R><e> E<w>-<e>R<w>-<e>R<w>-<e>O<w>-<e>R: </e></R></bo>’&
       ))
       write(*,*)
       write(*,’(a)’)attr(’<MYERROR> my custom message style’)

    end program demo_M_attr

AUTHOR

John S. Urban, 2021