#!/usr/local/bin/ici

/*
 * grep.ici - simple grep-like program in ICI
 */

static
grep(in, pattern)
{
    auto	regex;
    auto	line;

    regex = regexp(pattern);
    while (line = getline(in))	/* getline() returns NULL at eof */
	if (line ~ regex)	/* `~' is the "match" operator */
	    printf("%s\n", line);
}

if (argc < 2)
{
    printf(stderr, "usage: %s pattern [file...]\n", argv[0]);
    exit(1);
}

if (argc == 2)
    grep(stdin, argv[1]);
else
{
    auto f, fn;
    forall (fn in interval(argv, 2))
    {
	if (fn == "-")
	    grep(stdin, argv[1]);
	else
	{
	    grep(f = fopen(fn), argv[1]);
	    close(f);
	}
    }
}