functionusage

function usage() result(text)
    character(len=:), allocatable :: text
    character, parameter :: NL = achar(10)
    text = 'usage: fdoc [options] [project_file]'//NL//NL// &
           'Document a program or library written in modern Fortran. Command line options override'//NL// &
           'those in the project file. Without one, settings come from an [extra.fdoc] or'//NL// &
           '[extra.ford] table in fpm.toml, or from ford.md.'//NL//NL// &
           '  -d, --src_dir DIR        directory of source files (repeatable; default ./src)'//NL// &
           '  -p, --page_dir DIR       directory of static pages'//NL// &
           '  -o, --output_dir DIR     output directory (default ./doc)'//NL// &
           '  -s, --css FILE           custom style sheet'//NL// &
           '  -r, --revision REV       version or revision of the project'//NL// &
           '      --exclude FILE       file to leave out (repeatable)'//NL// &
           '      --exclude_dir DIR    directory to leave out (repeatable)'//NL// &
           '  -e, --extensions EXT     extension to scan (repeatable)'//NL// &
           '  -m, --macro MACRO        preprocessor macro (repeatable)'//NL// &
           '  -I, --include DIR        directory for include files (repeatable)'//NL// &
           '  -L, --external_links X   external project: name=path-or-url (repeatable)'//NL// &
           '  -w, --warn               warn about undocumented items'//NL// &
           '  -f, --force              continue reading files after fatal errors'//NL// &
           '  -g, --graph              generate graphs'//NL// &
           '      --no-search          do not build the search index'//NL// &
           '      --externalize        write modules.json for other projects (default)'//NL// &
           '      --no-externalize     do not write modules.json'//NL// &
           '  -q, --quiet              suppress normal output'//NL// &
           '      --debug              show details of fatal errors'//NL// &
           '      --config TOML        other options, as TOML with ; between lines'//NL// &
           '      --dump-settings      print the settings as JSON and stop'//NL// &
           '      --dump-links         print how entities are connected as JSON and stop'//NL// &
           '      --markdown-list FILE convert a JSON list of Markdown texts, to compare with FORD'//NL// &
           '  -V, --version            print the version'//NL// &
           '  -h, --help               print this help'//NL
end function usage