1 files changed, 97 insertions, 0 deletions
diff --git a/appl/alphabet/main/rewrite.b b/appl/alphabet/main/rewrite.b
new file mode 100644
index 00000000..96a6e205
--- /dev/null
+++ b/appl/alphabet/main/rewrite.b
@@ -0,0 +1,97 @@
+implement Rewrite, Mainmodule;
+include "sys.m";
+	sys: Sys;
+include "draw.m";
+include "sh.m";
+	sh: Sh;
+	Context: import sh;
+include "alphabet/reports.m";
+	reports: Reports;
+		report: import reports;
+include "alphabet.m";
+	Value: import Alphabet;
+
+Rewrite: module {};
+
+typesig(): string
+{
+	return "ccc-ds";
+}
+
+init()
+{
+	sys = load Sys Sys->PATH;
+	sh = load Sh Sh->PATH;
+	sh->initialise();
+	reports = load Reports Reports->PATH;
+}
+
+quit()
+{
+}
+
+run(drawctxt: ref Draw->Context, nil: ref Reports->Report, errorc: chan of string,
+		opts: list of (int, list of ref Value),
+		args: list of ref Value): ref Value
+{
+	c := chan of ref Value;
+	spawn rewriteproc(drawctxt, errorc, opts, args, c);
+	return <-c;
+}
+
+# we need a separate process so that we can create a shell context
+# without worrying about opening an already-opened wait file.
+rewriteproc(drawctxt: ref Draw->Context, errorc: chan of string,
+		opts: list of (int, list of ref Value),
+		args: list of ref Value,
+		c: chan of ref Value)
+{
+	c <-= rewrite(drawctxt, errorc, opts, args);
+}
+
+rewrite(drawctxt: ref Draw->Context, errorc: chan of string,
+		opts: list of (int, list of ref Value),
+		args: list of ref Value): ref Value
+{
+	alphabet := load Alphabet Alphabet->PATH;
+	if(alphabet == nil){
+		report(errorc, sys->sprint("rewrite: cannot load %q: %r", Alphabet->PATH));
+		return nil;
+	}
+	Value: import alphabet;
+	alphabet->init();
+	expr := (hd args).c().i;
+	decls := (hd tl args).c().i;
+	ctxt := Context.new(drawctxt);
+	{
+		ctxt.run(w("load")::w("alphabet")::nil, 0);
+		ctxt.run(c(decls) :: nil, 0);
+		dstarg: list of ref Sh->Listnode;
+		if(opts != nil)
+			dstarg = w((hd (hd opts).t1).s().i) :: nil;
+		ctxt.run(w("{x=${rewrite $1 $2}}") :: c(expr) :: dstarg, 0);
+	} exception e {
+	"fail:*" =>
+		ctxt.run(w("clear")::nil, 0);
+		report(errorc, "rewrite failed: "+e[5:]);
+		return nil;
+	}
+	r := ctxt.get("x");
+	if(len r != 2 || (hd r).cmd == nil){
+		ctxt.run(w("clear")::nil, 0);
+		report(errorc, "rewrite not available, strange... (len "+string len r+")");
+		return nil;
+	}
+	ctxt.run(w("clear")::nil, 0);
+	return ref Value.Vc((hd r).cmd);
+}
+
+c(c: ref Sh->Cmd): ref Sh->Listnode
+{
+	return ref Sh->Listnode(c, nil);
+}
+
+w(w: string): ref Sh->Listnode
+{
+	return ref Sh->Listnode(nil, w);
+}