hare

commit a3a879bcc37bca30406782da8bf32ab11182068c
parent 4cc6365d9adcc291e7352e652e035371cd9b9cec
Author: Byron Torres <b@torresjrjr.com>
Date:   Thu, 22 Feb 2024 23:44:03 +0000

time::date: make type insufficient an enum

Signed-off-by: Byron Torres <b@torresjrjr.com>

Diffstat:
M
time/date/error.ha
 | 
14
++++++++++++--
M
time/date/virtual.ha
 | 
26
++++++++++++++++++++------

2 files changed, 32 insertions(+), 8 deletions(-)
diff --git a/time/date/error.ha b/time/date/error.ha
@@ -2,6 +2,7 @@
 // (c) Hare authors <https://harelang.org>
 
 use fmt;
+use strings;
 
 // All possible errors returned from [[date]].
 export type error = !(insufficient | invalid | parsefail);
@@ -10,8 +11,17 @@ export type error = !(insufficient | invalid | parsefail);
 // statically allocated.
 export fn strerror(err: error) const str = {
 	match (err) {
-	case insufficient =>
-		return "Insufficient date information";
+	case let lack: insufficient =>
+		static let buf: [92]u8 = [0...];
+		return strings::rtrim(fmt::bsprint(buf,
+			"Insufficient date information, could not calculate:",
+			if (lack & insufficient::DAYDATE: u8 == 0) "" else
+				"daydate",
+			if (lack & insufficient::DAYTIME: u8 == 0) "" else
+				"time-of-day",
+			if (lack & insufficient::ZOFF: u8 == 0) "" else
+				"zone-offset",
+		));
 	case invalid =>
 		return "Invalid date information";
 	case let rn: parsefail =>
diff --git a/time/date/virtual.ha b/time/date/virtual.ha
@@ -5,7 +5,13 @@ use time;
 use time::chrono;
 
 // A [[virtual]] does not have enough information to create a valid [[date]].
-export type insufficient = !void;
+export type insufficient = !lack; // TODO: drop alias workaround
+
+export type lack = enum u8 {
+	DAYDATE = 1 << 0, // could not infer daydate
+	DAYTIME = 1 << 1, // could not infer time-of-day
+	ZOFF = 1 << 2,    // could not infer zone offset
+};
 
 // A virtual date; a [[date]] wrapper interface, which represents a date of
 // uncertain validity. Its fields need not be valid observed chronological
@@ -118,6 +124,8 @@ export fn realize(
 	v: virtual,
 	locs: chrono::locality...
 ) (date | insufficient | invalid) = {
+	let lacking = 0u8;
+
 	// determine .daydate
 	if (v.daydate is i64) {
 		void;
@@ -154,13 +162,13 @@ export fn realize(
 		void;
 	} else {
 		// cannot deduce daydate
-		return insufficient;
+		lacking |= insufficient::DAYDATE;
 	};
 
 	// determine .daytime
 	if (v.daytime is i64) {
 		void;
-	} else {
+	} else :nodaytime {
 		const hour = if (v.hour is int) {
 			yield v.hour as int;
 		} else if (v.halfhour is int && v.ampm is bool) {
@@ -168,7 +176,8 @@ export fn realize(
 			const pm = v.ampm as bool;
 			yield if (pm) hr * 2 else hr;
 		} else {
-			return insufficient;
+			lacking |= insufficient::DAYTIME;
+			yield :nodaytime;
 		};
 
 		if (
@@ -182,8 +191,9 @@ export fn realize(
 				v.second as int,
 				v.nanosecond as int,
 			)?;
+			lacking |= 0u8;
 		} else {
-			return insufficient;
+			lacking |= insufficient::DAYTIME;
 		};
 	};
 
@@ -191,7 +201,7 @@ export fn realize(
 	if (v.zoff is i64) {
 		void;
 	} else {
-		return insufficient;
+		lacking |= insufficient::ZOFF;
 	};
 
 	// determine .loc (defaults to time::chrono::UTC)
@@ -208,6 +218,10 @@ export fn realize(
 		};
 	};
 
+	if (lacking != 0u8) {
+		return lacking: insufficient;
+	};
+
 	// determine .sec, .nsec
 	const d = from_moment(chrono::from_datetime(
 		v.loc,