opt_get.awk

Basic example on how to use the opt module with the structured iterator API (opt::get), similar in style to the getopt and getopt_long command line argument parsers in C on Unix-like systems.

There also exists a gawk first-party version of getopt that is more similar to the C version and on which opt::get is based

#!/usr/bin/env -S gawk -E
@include "opt"
 
func main(    p, Opt, i, j, aflag) {
    # Defining the CLI
    opt::parser(p, "cli", "0.1.0", _"My CLI program")
    opt::flag(p, "a", "-a --alpha", _"Alpha option")
    opt::param(p, "b", "-b --beta", _"Beta option")
    opt::option(p, "c", "-c --ceta", _"Ceta option")
    opt::flag(p, "d", "-d --delta", _"Delta option")
 
    # Processing options as being encountered
    Opt["ind"] = 1
    while (opt::get(Opt, p, ARGV, ARGC)) {
        switch (Opt["c"]) {
        case "a":
            print Opt["opt"] _" was just encountered"
            # setting results for later use
            aflag = 1
            break
        case "b":
            print Opt["opt"] _" was just encountered with argument: " Opt["arg"]
            break
        case "c":
            print Opt["opt"] _" was just encountered with argument: " Opt["arg"]
            break
        case "\0":
            print _"unrecognized option just encountered" > "/dev/stderr"
            exit 22
        default:
            print _"other recognized option just encountered"
        }
    }
 
    # Now likely returns false unless you reset Opt["ind"], or you
    # could analize strings after a positionals separator "--"
    opt::get(Opt, p, ARGV, ARGC)
 
    # Processing after encountering
    if (aflag)
        print _"Something when -a or --alpha was passed"
 
    # Positional parameters
    i = Opt["ind"]
    if (i < ARGC)
        print _"Positional parameters:"
    for (; i < ARGC; i++)
        print "[" ++j "]: " ARGV[i]
}
 
BEGIN {
    exit main()
}