Actually implement printHelp
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Lyssieth
parent
d3703aa23d
commit
69b8839353
GPG key ID:
200268854934CFAB
1 changed files with 253 additions and 4 deletions
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@ -1,8 +1,257 @@
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const std = @import("std");
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pub fn printHelp(comptime T: type, writer: std.io.AnyWriter) !void {
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_ = T;
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_ = writer;
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const log = std.log.scoped(.help);
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const argLib = @import("args.zig");
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const Marker = argLib.Marker;
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const Extra = argLib.Extra;
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const niceTypeName = @import("utils.zig").niceTypeName;
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pub fn printHelp(comptime T: type, comptime name: []const u8, writer: std.io.AnyWriter) !void {
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const info = @typeInfo(T);
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switch (info) {
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.Struct => {},
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else => {
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log.warn("We only support printing the help of `Struct`s, not {s}", .{@tagName(info)});
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return error.NotImplemented;
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},
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}
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var hasFlags = false;
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inline for (info.Struct.fields) |field| {
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if (std.mem.eql(u8, field.name, "allocator")) {
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comptime continue;
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}
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if (field.type == Marker(bool)) {
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hasFlags = true;
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comptime break;
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}
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}
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var hasPositionals = false;
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inline for (info.Struct.fields) |field| {
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if (std.mem.eql(u8, field.name, "allocator")) {
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comptime continue;
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}
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const valueOpaque = field.default_value orelse @panic("Missing default value for field " ++ field.name);
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const valueMarker: *const field.type = @alignCast(@ptrCast(valueOpaque));
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const value: Extra = @field(valueMarker, "extra");
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switch (value) {
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.Positional => {
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hasPositionals = true;
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comptime break;
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},
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else => {},
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}
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}
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var hasRemainder = false;
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inline for (info.Struct.fields) |field| {
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if (std.mem.eql(u8, field.name, "allocator")) {
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comptime continue;
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}
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const valueOpaque = field.default_value orelse @panic("Missing default value for field " ++ field.name);
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const valueMarker: *const field.type = @alignCast(@ptrCast(valueOpaque));
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const value: Extra = @field(valueMarker, "extra");
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switch (value) {
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.Remainder => {
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hasRemainder = true;
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comptime break;
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},
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else => {},
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}
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}
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try writer.print("Usage: {s}", .{name});
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if (hasFlags) {
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try writer.print(" [flags]", .{});
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}
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if (hasPositionals) {
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inline for (info.Struct.fields) |field| {
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if (std.mem.eql(u8, field.name, "allocator")) {
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comptime continue;
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}
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const valueOpaque = field.default_value orelse @panic("Missing default value for field " ++ field.name);
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const valueMarker: *const field.type = @alignCast(@ptrCast(valueOpaque));
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const value: Extra = @field(valueMarker, "extra");
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switch (value) {
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.Positional => {
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try writer.print(" <{s}>", .{field.name});
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},
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else => {},
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}
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}
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}
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if (hasRemainder) {
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try writer.print(" [...]", .{});
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}
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try writer.print("\n", .{});
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try writer.print("Legend: <required> [optional]\n\n", .{});
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inline for (info.Struct.fields) |field| {
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if (std.mem.eql(u8, field.name, "allocator")) {
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comptime continue;
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}
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const valueOpaque = field.default_value orelse @panic("Missing default value for field " ++ field.name);
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const valueMarker: *const field.type = @alignCast(@ptrCast(valueOpaque));
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const valueType = niceTypeName(@TypeOf(valueMarker.*.value));
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const isOptional = std.mem.startsWith(u8, valueType, "?");
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switch (valueMarker.*.extra) {
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.Remainder => {
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comptime continue;
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},
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.Positional => |pos| {
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try writer.print("* <{s}>: {s}", .{
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field.name,
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valueType,
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});
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if (pos.typeHint) |typeHint| {
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try writer.print(" ({s})", .{typeHint});
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}
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if (pos.about) |about| {
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try writer.print(" | {s}", .{about});
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}
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},
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.Flag => |flag| {
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try writer.print("* ", .{});
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try writer.print("--{s}", .{
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flag.name,
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});
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if (flag.takesValue) {
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try writer.print("=<value>", .{});
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}
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if (flag.short) |short| {
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try writer.print(" (-{s}", .{short});
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if (flag.takesValue) {
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try writer.print("=<value>", .{});
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}
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try writer.print(")", .{});
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}
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try writer.print(": {s}", .{valueType});
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if (flag.typeHint) |typeHint| {
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try writer.print(" ({s})", .{typeHint});
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}
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if (!isOptional) {
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try writer.print(" <required>", .{});
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}
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if (flag.about) |about| {
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try writer.print(" | {s}", .{about});
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}
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},
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}
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try writer.print("\n", .{});
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}
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}
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const t = std.testing;
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test "empty help" {
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var buf = std.ArrayList(u8).init(t.allocator);
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defer buf.deinit();
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const Demo = struct {};
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try printHelp(Demo, "demo", buf.writer().any());
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try t.expectEqualStrings(
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\\Usage: demo
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\\Legend: <required> [optional]
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\\
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\\
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, buf.items);
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}
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test "basic help" {
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var buf = std.ArrayList(u8).init(t.allocator);
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defer buf.deinit();
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const Demo = struct {
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verbose: Marker(bool) = Marker(bool){
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.value = undefined,
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.extra = .{
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.Flag = .{
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.name = "verbose",
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.short = "v",
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.takesValue = false,
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.toggle = true,
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},
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},
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},
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positional: Marker([]const u8) = Marker([]const u8){
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.value = undefined,
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.extra = .{ .Positional = .{} },
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},
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remainder: Marker(std.ArrayList([]const u8)) = Marker(std.ArrayList([]const u8)){
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.value = undefined,
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.extra = .{ .Remainder = {} },
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},
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};
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try printHelp(Demo, "demo", buf.writer().any());
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try t.expectEqualStrings(
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\\Usage: demo [flags] <positional> [...]
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\\Legend: <required> [optional]
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\\
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\\* --verbose (-v): bool <required>
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\\* <positional>: string
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\\
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, buf.items);
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}
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test "about and type hint" {
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var buf = std.ArrayList(u8).init(t.allocator);
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defer buf.deinit();
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const Demo = struct {
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verbose: Marker(bool) = Marker(bool){
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.value = undefined,
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.extra = .{ .Flag = .{
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.name = "verbose",
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.short = "v",
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.takesValue = true,
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.about = "makes the output verbose",
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.typeHint = "yes/no",
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} },
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},
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};
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try printHelp(Demo, "demo", buf.writer().any());
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try t.expectEqualStrings(
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\\Usage: demo [flags]
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\\Legend: <required> [optional]
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\\
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\\* --verbose=<value> (-v=<value>): bool (yes/no) <required> | makes the output verbose
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\\
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, buf.items);
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}
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