1 files changed, 60 insertions, 0 deletions
diff --git a/appl/alphabet/fs/select.b b/appl/alphabet/fs/select.b
new file mode 100644
index 00000000..8a44104d
--- /dev/null
+++ b/appl/alphabet/fs/select.b
@@ -0,0 +1,60 @@
+implement Select, Fsmodule;
+include "sys.m";
+	sys: Sys;
+include "draw.m";
+include "sh.m";
+include "alphabet/reports.m";
+	Report: import Reports;
+include "alphabet/fs.m";
+	fs: Fs;
+	Value: import fs;
+	Fschan, Fsdata, Entrychan, Entry,
+	Gatechan, Gatequery, Nilentry, Option,
+	Next, Down, Skip, Quit: import Fs;
+
+Select: module {};
+types(): string
+{
+	return "ttp";
+}
+
+badmod(p: string)
+{
+	sys->fprint(sys->fildes(2), "fs: size: cannot load %s: %r\n", p);
+	raise "fail:bad module";
+}
+
+init()
+{
+	sys = load Sys Sys->PATH;
+	fs = load Fs Fs->PATH;
+	if(fs == nil)
+		badmod(Fs->PATH);
+	fs->init();
+}
+
+run(nil: ref Draw->Context, nil: ref Report,
+			nil: list of Option, args: list of ref Value): ref Value
+{
+	dst := Entrychan(chan of int, chan of Entry);
+	spawn selectproc((hd args).t().i, dst, (hd tl args).p().i);
+	return ref Value.Vt(dst);
+}
+
+selectproc(src, dst: Entrychan, query: Gatechan)
+{
+	if(<-dst.sync == 0){
+		query <-= (Nilentry, nil);
+		src.sync <-= 0;
+		exit;
+	}
+	src.sync <-= 1;
+	reply := chan of int;
+	while((d := <-src.c).t0 != nil){
+		query <-= (d, reply);
+		if(<-reply)
+			dst.c <-= d;
+	}
+	dst.c <-= Nilentry;
+	query <-= (Nilentry, nil);
+}