commit 3fdb990fbffa911bb03f5ab578a159da25c4dc5a Author: Marto Date: Tue Mar 17 13:00:05 2026 +0100 Initial commit diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..5a8ed86 --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +/zig-out/ +/.zig-cache/ +/.idea/ diff --git a/build.zig b/build.zig new file mode 100644 index 0000000..1b5a444 --- /dev/null +++ b/build.zig @@ -0,0 +1,156 @@ +const std = @import("std"); + +// Although this function looks imperative, it does not perform the build +// directly and instead it mutates the build graph (`b`) that will be then +// executed by an external runner. The functions in `std.Build` implement a DSL +// for defining build steps and express dependencies between them, allowing the +// build runner to parallelize the build automatically (and the cache system to +// know when a step doesn't need to be re-run). +pub fn build(b: *std.Build) void { + // Standard target options allow the person running `zig build` to choose + // what target to build for. Here we do not override the defaults, which + // means any target is allowed, and the default is native. Other options + // for restricting supported target set are available. + const target = b.standardTargetOptions(.{}); + // Standard optimization options allow the person running `zig build` to select + // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not + // set a preferred release mode, allowing the user to decide how to optimize. + const optimize = b.standardOptimizeOption(.{}); + // It's also possible to define more custom flags to toggle optional features + // of this build script using `b.option()`. All defined flags (including + // target and optimize options) will be listed when running `zig build --help` + // in this directory. + + // This creates a module, which represents a collection of source files alongside + // some compilation options, such as optimization mode and linked system libraries. + // Zig modules are the preferred way of making Zig code available to consumers. + // addModule defines a module that we intend to make available for importing + // to our consumers. We must give it a name because a Zig package can expose + // multiple modules and consumers will need to be able to specify which + // module they want to access. + // const mod = b.addModule("number_formatting", .{ + // // The root source file is the "entry point" of this module. Users of + // // this module will only be able to access public declarations contained + // // in this file, which means that if you have declarations that you + // // intend to expose to consumers that were defined in other files part + // // of this module, you will have to make sure to re-export them from + // // the root file. + // .root_source_file = b.path("src/root.zig"), + // // Later on we'll use this module as the root module of a test executable + // // which requires us to specify a target. + // .target = target, + // }); + + // Here we define an executable. An executable needs to have a root module + // which needs to expose a `main` function. While we could add a main function + // to the module defined above, it's sometimes preferable to split business + // logic and the CLI into two separate modules. + // + // If your goal is to create a Zig library for others to use, consider if + // it might benefit from also exposing a CLI tool. A parser library for a + // data serialization format could also bundle a CLI syntax checker, for example. + // + // If instead your goal is to create an executable, consider if users might + // be interested in also being able to embed the core functionality of your + // program in their own executable in order to avoid the overhead involved in + // subprocessing your CLI tool. + // + // If neither case applies to you, feel free to delete the declaration you + // don't need and to put everything under a single module. + const exe = b.addExecutable(.{ + .name = "number_formatting", + .root_module = b.createModule(.{ + // b.createModule defines a new module just like b.addModule but, + // unlike b.addModule, it does not expose the module to consumers of + // this package, which is why in this case we don't have to give it a name. + .root_source_file = b.path("src/main.zig"), + // Target and optimization levels must be explicitly wired in when + // defining an executable or library (in the root module), and you + // can also hardcode a specific target for an executable or library + // definition if desireable (e.g. firmware for embedded devices). + .target = target, + .optimize = optimize, + // List of modules available for import in source files part of the + // root module. + .imports = &.{ + // Here "number_formatting" is the name you will use in your source code to + // import this module (e.g. `@import("number_formatting")`). The name is + // repeated because you are allowed to rename your imports, which + // can be extremely useful in case of collisions (which can happen + // importing modules from different packages). + // .{ .name = "number_formatting", .module = mod }, + }, + }), + }); + + // This declares intent for the executable to be installed into the + // install prefix when running `zig build` (i.e. when executing the default + // step). By default the install prefix is `zig-out/` but can be overridden + // by passing `--prefix` or `-p`. + b.installArtifact(exe); + + // This creates a top level step. Top level steps have a name and can be + // invoked by name when running `zig build` (e.g. `zig build run`). + // This will evaluate the `run` step rather than the default step. + // For a top level step to actually do something, it must depend on other + // steps (e.g. a Run step, as we will see in a moment). + const run_step = b.step("run", "Run the app"); + + // This creates a RunArtifact step in the build graph. A RunArtifact step + // invokes an executable compiled by Zig. Steps will only be executed by the + // runner if invoked directly by the user (in the case of top level steps) + // or if another step depends on it, so it's up to you to define when and + // how this Run step will be executed. In our case we want to run it when + // the user runs `zig build run`, so we create a dependency link. + const run_cmd = b.addRunArtifact(exe); + run_step.dependOn(&run_cmd.step); + + // By making the run step depend on the default step, it will be run from the + // installation directory rather than directly from within the cache directory. + run_cmd.step.dependOn(b.getInstallStep()); + + // This allows the user to pass arguments to the application in the build + // command itself, like this: `zig build run -- arg1 arg2 etc` + if (b.args) |args| { + run_cmd.addArgs(args); + } + + // Creates an executable that will run `test` blocks from the provided module. + // Here `mod` needs to define a target, which is why earlier we made sure to + // set the releative field. + // const mod_tests = b.addTest(.{ + // .root_module = mod, + // }); + + // A run step that will run the test executable. + // const run_mod_tests = b.addRunArtifact(mod_tests); + + // Creates an executable that will run `test` blocks from the executable's + // root module. Note that test executables only test one module at a time, + // hence why we have to create two separate ones. + const exe_tests = b.addTest(.{ + .root_module = exe.root_module, + }); + + // A run step that will run the second test executable. + const run_exe_tests = b.addRunArtifact(exe_tests); + + // A top level step for running all tests. dependOn can be called multiple + // times and since the two run steps do not depend on one another, this will + // make the two of them run in parallel. + const test_step = b.step("test", "Run tests"); + // test_step.dependOn(&run_mod_tests.step); + test_step.dependOn(&run_exe_tests.step); + + // Just like flags, top level steps are also listed in the `--help` menu. + // + // The Zig build system is entirely implemented in userland, which means + // that it cannot hook into private compiler APIs. All compilation work + // orchestrated by the build system will result in other Zig compiler + // subcommands being invoked with the right flags defined. You can observe + // these invocations when one fails (or you pass a flag to increase + // verbosity) to validate assumptions and diagnose problems. + // + // Lastly, the Zig build system is relatively simple and self-contained, + // and reading its source code will allow you to master it. +} diff --git a/build.zig.zon b/build.zig.zon new file mode 100644 index 0000000..46ce56d --- /dev/null +++ b/build.zig.zon @@ -0,0 +1,81 @@ +.{ + // This is the default name used by packages depending on this one. For + // example, when a user runs `zig fetch --save `, this field is used + // as the key in the `dependencies` table. Although the user can choose a + // different name, most users will stick with this provided value. + // + // It is redundant to include "zig" in this name because it is already + // within the Zig package namespace. + .name = .number_formatting, + // This is a [Semantic Version](https://semver.org/). + // In a future version of Zig it will be used for package deduplication. + .version = "0.0.0", + // Together with name, this represents a globally unique package + // identifier. This field is generated by the Zig toolchain when the + // package is first created, and then *never changes*. This allows + // unambiguous detection of one package being an updated version of + // another. + // + // When forking a Zig project, this id should be regenerated (delete the + // field and run `zig build`) if the upstream project is still maintained. + // Otherwise, the fork is *hostile*, attempting to take control over the + // original project's identity. Thus it is recommended to leave the comment + // on the following line intact, so that it shows up in code reviews that + // modify the field. + .fingerprint = 0xa2477d49d78706f9, // Changing this has security and trust implications. + // Tracks the earliest Zig version that the package considers to be a + // supported use case. + .minimum_zig_version = "0.15.2", + // This field is optional. + // Each dependency must either provide a `url` and `hash`, or a `path`. + // `zig build --fetch` can be used to fetch all dependencies of a package, recursively. + // Once all dependencies are fetched, `zig build` no longer requires + // internet connectivity. + .dependencies = .{ + // See `zig fetch --save ` for a command-line interface for adding dependencies. + //.example = .{ + // // When updating this field to a new URL, be sure to delete the corresponding + // // `hash`, otherwise you are communicating that you expect to find the old hash at + // // the new URL. If the contents of a URL change this will result in a hash mismatch + // // which will prevent zig from using it. + // .url = "https://example.com/foo.tar.gz", + // + // // This is computed from the file contents of the directory of files that is + // // obtained after fetching `url` and applying the inclusion rules given by + // // `paths`. + // // + // // This field is the source of truth; packages do not come from a `url`; they + // // come from a `hash`. `url` is just one of many possible mirrors for how to + // // obtain a package matching this `hash`. + // // + // // Uses the [multihash](https://multiformats.io/multihash/) format. + // .hash = "...", + // + // // When this is provided, the package is found in a directory relative to the + // // build root. In this case the package's hash is irrelevant and therefore not + // // computed. This field and `url` are mutually exclusive. + // .path = "foo", + // + // // When this is set to `true`, a package is declared to be lazily + // // fetched. This makes the dependency only get fetched if it is + // // actually used. + // .lazy = false, + //}, + }, + // Specifies the set of files and directories that are included in this package. + // Only files and directories listed here are included in the `hash` that + // is computed for this package. Only files listed here will remain on disk + // when using the zig package manager. As a rule of thumb, one should list + // files required for compilation plus any license(s). + // Paths are relative to the build root. Use the empty string (`""`) to refer to + // the build root itself. + // A directory listed here means that all files within, recursively, are included. + .paths = .{ + "build.zig", + "build.zig.zon", + "src", + // For example... + //"LICENSE", + //"README.md", + }, +} diff --git a/src/main.zig b/src/main.zig new file mode 100644 index 0000000..c5a0279 --- /dev/null +++ b/src/main.zig @@ -0,0 +1,83 @@ +const std = @import("std"); + +pub fn main() !void { + // var gpa: std.heap.DebugAllocator(.{}) = .init; + // defer _ = gpa.deinit(); + // var allocator = gpa.allocator(); + + var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator); + defer arena.deinit(); + var allocator = arena.allocator(); + + const input = try getInput("Please enter a number: "); + const format_num = try formatNumber(input, allocator); + defer allocator.free(format_num); + + var stdout_buffer: [100]u8 = undefined; + var stdout = std.fs.File.stdout().writer(&stdout_buffer); + var output = &stdout.interface; + + try output.print("{s}\n", .{format_num}); + try output.flush(); +} + +fn getInput(message: []const u8) !i32 { + var stdout_buffer: [100]u8 = undefined; + var stdout = std.fs.File.stdout().writer(&stdout_buffer); + var output = &stdout.interface; + + var stdin_buffer: [100]u8 = undefined; + var stdin = std.fs.File.stdin().reader(&stdin_buffer); + + var line_buffer: [100]u8 = undefined; + var w: std.io.Writer = .fixed(&line_buffer); + + while (true) { + w.end = 0; // reads to position 0 in buffer, instead of concatanating further ahead + try output.writeAll(message); + try output.flush(); + + const line_length = try stdin.interface.streamDelimiterLimit(&w, '\n', .unlimited); + // goes one byte ahead so it doesn't get caught in an infinite loop when stdin notices '\n' in its buffer and skips reading user input alltogether + stdin.interface.toss(1); + + const input_line = line_buffer[0..line_length]; + + const res = std.fmt.parseInt(i32, input_line, 10) catch { + continue; + }; + return res; + } +} + +fn formatNumber(number: i32, allocator: std.mem.Allocator) ![]const u8 { + var abs_num = @abs(number); + const len = if (abs_num == 0) 1 else std.math.log10(abs_num) + 1; + var delimiter_len = len / 3; + if (len % 3 == 0) delimiter_len -= 1; + + var format_len = len + delimiter_len; + if (number < 0) format_len += 1; + + var format_num = try allocator.alloc(u8, format_len); + var fn_i: usize = format_len - 1; + + for (1..len + 1) |i| { + const r = @as(u8, @intCast(abs_num % 10)); + abs_num /= 10; + + format_num[fn_i] = r + '0'; // write digit in ascii (char) + if (fn_i == 0) break; + fn_i -= 1; + + if (i % 3 == 0 and i < len) { + format_num[fn_i] = '.'; + fn_i -= 1; + } + } + if (number < 0) { + format_num[0] = '-'; + } + + return format_num; +} \ No newline at end of file