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implement Shellbuiltin;
include "sys.m";
sys: Sys;
include "draw.m";
include "sh.m";
sh: Sh;
Listnode, Context: import sh;
myself: Shellbuiltin;
initbuiltin(ctxt: ref Context, shmod: Sh): string
{
sys = load Sys Sys->PATH;
sh = shmod;
myself = load Shellbuiltin "$self";
if (myself == nil)
ctxt.fail("bad module", sys->sprint("echo: cannot load self: %r"));
ctxt.addbuiltin("echo", myself);
return nil;
}
whatis(nil: ref Sh->Context, nil: Sh, nil: string, nil: int): string
{
return nil;
}
getself(): Shellbuiltin
{
return myself;
}
runbuiltin(ctxt: ref Context, nil: Sh,
argv: list of ref Listnode, last: int): string
{
case (hd argv).word {
"echo" =>
return builtin_echo(ctxt, argv, last);
}
return nil;
}
runsbuiltin(nil: ref Sh->Context, nil: Sh,
nil: list of ref Listnode): list of ref Listnode
{
return nil;
}
argusage(ctxt: ref Context)
{
ctxt.fail("usage", "usage: arg [opts {command}]... - args");
}
# converted from /appl/cmd/echo.b.
# should have exactly the same semantics.
builtin_echo(nil: ref Context, argv: list of ref Listnode, nil: int): string
{
argv = tl argv;
nonewline := 0;
if (len argv > 0) {
w := (hd argv).word;
if (w == "-n" || w == "--") {
nonewline = (w == "-n");
argv = tl argv;
}
}
s := "";
if (argv != nil) {
s = word(hd argv);
for (argv = tl argv; argv != nil; argv = tl argv)
s += " " + word(hd argv);
}
if (nonewline == 0)
s[len s] = '\n';
{
a := array of byte s;
if (sys->write(sys->fildes(1), a, len a) != len a) {
sys->fprint(sys->fildes(2), "echo: write error: %r\n");
return "write error";
}
return nil;
}
exception{
"write on closed pipe" =>
sys->fprint(sys->fildes(2), "echo: write error: write on closed pipe\n");
return "write error";
}
}
word(n: ref Listnode): string
{
if (n.word != nil)
return n.word;
if (n.cmd != nil)
n.word = sh->cmd2string(n.cmd);
return n.word;
}
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