fix: Remove the lagcy code

build.zig

@@ -1,70 +1,14 @@
 const std = @import("std");
 
-// Although this function looks imperative, note that its job is to
-// declaratively construct a build graph that will be executed by an external
-// runner.
 pub fn build(b: *std.Build) void {
-    // Standard target options allows 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(.{});
-
     const exe = b.addExecutable(.{
         .name = "zig_fmt",
-        // In this case the main source file is merely a path, however, in more
-        // complicated build scripts, this could be a generated file.
         .root_source_file = b.path("src/main.zig"),
         .target = target,
         .optimize = optimize,
     });
 
-    // This declares intent for the executable to be installed into the
-    // standard location when the user invokes the "install" step (the default
-    // step when running `zig build`).
     b.installArtifact(exe);
-
-    // This *creates* a Run step in the build graph, to be executed when another
-    // step is evaluated that depends on it. The next line below will establish
-    // such a dependency.
-    const run_cmd = b.addRunArtifact(exe);
-
-    // By making the run step depend on the install step, it will be run from the
-    // installation directory rather than directly from within the cache directory.
-    // This is not necessary, however, if the application depends on other installed
-    // files, this ensures they will be present and in the expected location.
-    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);
-    }
-
-    // This creates a build step. It will be visible in the `zig build --help` menu,
-    // and can be selected like this: `zig build run`
-    // This will evaluate the `run` step rather than the default, which is "install".
-    const run_step = b.step("run", "Run the app");
-    run_step.dependOn(&run_cmd.step);
-
-    // Creates a step for unit testing. This only builds the test executable
-    // but does not run it.
-    const unit_tests = b.addTest(.{
-        .root_source_file = b.path("src/main.zig"),
-        .target = target,
-        .optimize = optimize,
-    });
-
-    const run_unit_tests = b.addRunArtifact(unit_tests);
-
-    // Similar to creating the run step earlier, this exposes a `test` step to
-    // the `zig build --help` menu, providing a way for the user to request
-    // running the unit tests.
-    const test_step = b.step("test", "Run unit tests");
-    test_step.dependOn(&run_unit_tests.step);
 }

src/main.zig

@@ -1,84 +1,19 @@
 const std = @import("std");
-const builtin = @import("builtin");
-
-const io = std.io;
-const fs = std.fs;
-const mem = std.mem;
-const Allocator = mem.Allocator;
-const process = std.process;
 
 pub fn main() !void {
-    const stdin = io.getStdIn();
-    const stdout = io.getStdOut().writer();
-
-    const allocator = gpa: {
-        if (builtin.os.tag == .wasi) {
-            break :gpa std.heap.wasm_allocator;
-        }
-        // We would prefer to use raw libc allocator here, but cannot
-        // use it if it won't support the alignment we need.
-        if (@alignOf(std.c.max_align_t) < @alignOf(i128)) {
-            break :gpa std.heap.c_allocator;
-        }
-        break :gpa std.heap.raw_c_allocator;
-    };
-
-    const source_code = try readSourceFileToEndAlloc(allocator, &stdin, null);
-
-    var tree = try std.zig.Ast.parse(allocator, source_code, .zig);
-    defer tree.deinit(allocator);
-
-    const formatted = try tree.render(allocator);
-    defer allocator.free(formatted);
-    try stdout.writeAll(formatted);
-}
-
-const max_src_size = std.math.maxInt(u32);
-
-fn readSourceFileToEndAlloc(
-    allocator: Allocator,
-    input: *const fs.File,
-    size_hint: ?usize,
-) ![:0]u8 {
-    const source_code = input.readToEndAllocOptions(
-        allocator,
-        max_src_size,
-        size_hint,
-        @alignOf(u16),
-        0,
-    ) catch |err| switch (err) {
-        error.ConnectionResetByPeer => unreachable,
-        error.ConnectionTimedOut => unreachable,
-        error.NotOpenForReading => unreachable,
-        else => |e| return e,
-    };
-    errdefer allocator.free(source_code);
-
-    // Detect unsupported file types with their Byte Order Mark
-    const unsupported_boms = [_][]const u8{
-        "\xff\xfe\x00\x00", // UTF-32 little endian
-        "\xfe\xff\x00\x00", // UTF-32 big endian
-        "\xfe\xff", // UTF-16 big endian
-    };
-    for (unsupported_boms) |bom| {
-        if (mem.startsWith(u8, source_code, bom)) {
-            return error.UnsupportedEncoding;
-        }
-    }
+    var arena_instance = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena_instance.deinit();
+    const arena = arena_instance.allocator();
+    const gpa = arena;
 
-    // If the file starts with a UTF-16 little endian BOM, translate it to UTF-8
-    if (mem.startsWith(u8, source_code, "\xff\xfe")) {
-        const source_code_utf16_le = mem.bytesAsSlice(u16, source_code);
-        const source_code_utf8 = std.unicode.utf16leToUtf8AllocZ(allocator, source_code_utf16_le) catch |err| switch (err) {
-            error.DanglingSurrogateHalf => error.UnsupportedEncoding,
-            error.ExpectedSecondSurrogateHalf => error.UnsupportedEncoding,
-            error.UnexpectedSecondSurrogateHalf => error.UnsupportedEncoding,
-            else => |e| return e,
-        };
+    const stdin = std.io.getStdIn();
+    const source_code = try std.zig.readSourceFileToEndAlloc(gpa, stdin, null);
+    defer gpa.free(source_code);
 
-        allocator.free(source_code);
-        return source_code_utf8;
-    }
+    var tree = try std.zig.Ast.parse(gpa, source_code, .zig);
+    defer tree.deinit(gpa);
 
-    return source_code;
+    const formatted = try tree.render(gpa);
+    defer gpa.free(formatted);
+    return std.io.getStdOut().writeAll(formatted);
 }