String Builder

const std = @import("std");pub const StringBuilder = struct {    list: std.ArrayList(u8),        pub fn init(allocator: std.mem.Allocator) StringBuilder {        return StringBuilder{            .list = std.ArrayList(u8).init(allocator),        };    }        pub fn initWithCapacity(allocator: std.mem.Allocator, capacity: usize) StringBuilder {        var sb = StringBuilder{            .list = std.ArrayList(u8).init(allocator),        };        sb.list.ensureTotalCapacity(capacity) catch {};        return sb;    }        pub fn append(self: *StringBuilder, str: []const u8) !void {        try self.list.appendSlice(str);    }        pub fn appendChar(self: *StringBuilder, c: u8) !void {        try self.list.append(c);    }        pub fn appendFormat(self: *StringBuilder, comptime fmt: []const u8, args: anytype) !void {        try std.fmt.format(self.list.writer(), fmt, args);    }        pub fn appendLine(self: *StringBuilder, str: []const u8) !void {        try self.append(str);        try self.appendChar('\n');    }        pub fn build(self: *StringBuilder) ![]u8 {        return try self.list.toOwnedSlice();    }        pub fn deinit(self: *StringBuilder) void {        self.list.deinit();    }        pub fn len(self: *const StringBuilder) usize {        return self.list.items.len;    }        pub fn clear(self: *StringBuilder) void {        self.list.clearAndFree();    }};

const std = @import("std");const StringBuilder = @import("string_builder.zig").StringBuilder;pub fn main() !void {    var gpa = std.heap.GeneralPurposeAllocator(.{}){};    defer _ = gpa.deinit();    const allocator = gpa.allocator();        var sb = StringBuilder.initWithCapacity(allocator, 100);    defer sb.deinit();        try sb.append("Hello");    try sb.append(" ");    try sb.append("World");    try sb.appendChar('!');    try sb.appendLine("This is a line");        const result = try sb.build();    defer allocator.free(result);        std.debug.print("{s}\n", .{result});}