dicer

commit 6700b341468b219f2cfc748fa59a9e38367aea7d
parent 78859e9353d148fbf0e72d6d7379884b1484634f
Author: Martin Ashby <martin@ashbysoft.com>
Date:   Fri,  9 Aug 2024 23:04:49 +0100

Improved error handling

Diffstat:
M
src/main.zig
 | 
37
+++----------------------------------
M
src/root.zig
 | 
41
+++++++++++++++++++++++++++++++++++++----

2 files changed, 40 insertions(+), 38 deletions(-)
diff --git a/src/main.zig b/src/main.zig
@@ -1,40 +1,9 @@
 const std = @import("std");
-
-const usage =
-    \\Usage: 
-    \\ dicer XdY
-    \\
-    \\Rolls X dice with Y
-    \\
-;
+const dicer = @import("root.zig").dicer;
 
 pub fn main() !void {
     var args = std.process.args();
     _ = args.skip(); // program name
-    const dice_str = args.next() orelse {
-        try printUsage();
-        return;
-    };
-
-    var spl = std.mem.splitScalar(u8, dice_str, 'd');
-    const count = try std.fmt.parseInt(u64, spl.first(), 10);
-    const sides = try std.fmt.parseInt(u64, spl.next() orelse "6", 10);
-    var wtr = std.io.getStdOut().writer();
-    try wtr.writeAll("Dice roll: ");
-    var total: u64 = 0;
-    for (0..count) |_| {
-        const res = roll(sides);
-        try std.fmt.format(wtr, "{} ", .{res});
-        total += res;
-    }
-    try std.fmt.format(wtr, " total: {}", .{total});
-    try wtr.writeByte('\n');
-}
-
-fn roll(dsize: u64) u64 {
-    return (std.crypto.random.int(u64) % dsize) + 1;
-}
-
-fn printUsage() !void {
-    try std.fmt.format(std.io.getStdOut(), usage, .{});
+    const wtr = std.io.getStdOut().writer();
+    try dicer(&args, wtr);
 }
diff --git a/src/root.zig b/src/root.zig
@@ -1,10 +1,43 @@
 const std = @import("std");
 const testing = std.testing;
 
-export fn add(a: i32, b: i32) i32 {
-    return a + b;
+pub fn dicer(args: anytype, wtr: anytype) !void {
+    doDicer(args, wtr) catch |e| switch (e) {
+        error.MissingArg, error.InvalidCharacter => {
+            try printUsage(wtr);
+            return;
+        },
+        else => return e,
+    };
 }
 
-test "basic add functionality" {
-    try testing.expect(add(3, 7) == 10);
+fn doDicer(args: anytype, wtr: anytype) !void {
+    const dice_str = args.next() orelse return error.MissingArg;
+    var spl = std.mem.splitScalar(u8, dice_str, 'd');
+    const count = try std.fmt.parseInt(u64, spl.first(), 10);
+    const sides = try std.fmt.parseInt(u64, spl.next() orelse "6", 10);
+
+    try wtr.writeAll("Dice roll: ");
+    var total: u64 = 0;
+    for (0..count) |_| {
+        const res = roll(sides);
+        try std.fmt.format(wtr, "{} ", .{res});
+        total += res;
+    }
+    try std.fmt.format(wtr, " total: {}", .{total});
+    try wtr.writeByte('\n');
+}
+
+fn roll(dsize: u64) u64 {
+    return (std.crypto.random.int(u64) % dsize) + 1;
+}
+
+fn printUsage(wtr: anytype) !void {
+    try std.fmt.format(wtr,
+        \\Usage: 
+        \\ dicer XdY
+        \\
+        \\Rolls X dice with Y
+        \\
+    , .{});
 }