ed

commit b459d51057d6791a1cac2eaca0f471dc4b9e3ef1
parent 078ab7e5f7f943c82e37467a0892805f7747caef
Author: Byron Torres <b@torresjrjr.com>
Date:   Thu,  9 Sep 2021 03:00:28 +0100

Parse file argument

Diffstat:
M
ed.ha
 | 
23
+++++++++++++++++++++++

1 file changed, 23 insertions(+), 0 deletions(-)
diff --git a/ed.ha b/ed.ha
@@ -1,6 +1,12 @@
+use fmt;
+use fs;
 use getopt;
+use io;
 use os;
 
+type filename = (str | void);
+type file = (io::file | void);
+
 export fn main() void = {
 	const help: [_]getopt::help = [
 		"standard line editor",
@@ -25,6 +31,23 @@ export fn main() void = {
 	if (len(cmd.args) > 1) {
 		exit_usage(help);
 	};
+
+	let filename: filename = switch (len(cmd.args) == 1) {
+		false => void,
+		true  => switch (cmd.args[0]) {
+			"-" => fmt::fatal("Invalid filename '-'"),
+			""  => fmt::fatal("Invalid filename ''"),
+			*   => cmd.args[0],
+		},
+	};
+
+	let file: file = match (filename) {
+		void => void,
+		filename: str => match (os::open(filename)) {
+			err: fs::error => fmt::fatal("Error {}", fs::strerror(err)),
+			file: io::file => file,
+		},
+	};
 };
 
 @noreturn fn exit_usage(help: []getopt::help) void = {