ref: b502a62da2ec6058923db94f87ecc2d29db2fa77
dir: /appl/cmd/xargs.b/
# apply cmd to args list read from stdin # obc implement Xargs; include "sys.m"; sys: Sys; include "draw.m"; include "sh.m"; include "bufio.m"; bufio: Bufio; Iobuf: import bufio; Xargs: module { init: fn(ctxt: ref Draw->Context, argv: list of string); }; stderr: ref Sys->FD; usage() { sys->fprint(stderr, "Usage: xargs command [command args] <[list of last command arg]\n"); } init(ctxt: ref Draw->Context, args: list of string) { sys = load Sys Sys->PATH; stderr = sys->fildes(2); bufio = load Bufio Bufio->PATH; if(bufio == nil){ sys->fprint(stderr, "xargs: can't load Bufio: %r\n"); exit; } if(args != nil) args = tl args; if (args == nil) { usage(); return; } cmd := hd args; args = tl args; if(len cmd < 4 || cmd[len cmd -4:]!=".dis") cmd += ".dis"; sh := load Command cmd; if (sh == nil){ cmd = "/dis/"+cmd; sh = load Command cmd; } if (sh == nil){ sys->fprint(stderr, "xargs: can't load %s: %r\n", cmd); exit; } stdin := sys->fildes(0); if(stdin == nil){ sys->fprint(stderr, "xargs: no standard input\n"); exit; } b := bufio->fopen(stdin, Bufio->OREAD); while((t := b.gets('\n')) != nil){ (nil, rargs) := sys->tokenize(t, " \t\n"); if (rargs == nil) continue; if (args == nil) rargs = cmd :: rargs; else rargs = append(cmd :: args, rargs); sh->init(ctxt, rargs); # BUG: process environment? } } reverse[T](l: list of T): list of T { t: list of T; for(; l != nil; l = tl l) t = hd l :: t; return t; } append(h, t: list of string) : list of string { r := reverse(h); for(; r != nil; r = tl r) t = hd r :: t; return t; }