Initial commit

.gitignore

@@ -0,0 +1,2 @@
+.zig-cache/
+zig-out/

LICENSE

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+MIT License
+
+Copyright (c) 2024 Cameron Reed
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

build.zig

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+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 lib = b.addStaticLibrary(.{
+        .name = "zig-args",
+        // 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/root.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    // This declares intent for the library to be installed into the standard
+    // location when the user invokes the "install" step (the default step when
+    // running `zig build`).
+    b.installArtifact(lib);
+
+    const exe = b.addExecutable(.{
+        .name = "zig-args-test",
+        .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 lib_unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/root.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);
+
+    const exe_unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_exe_unit_tests = b.addRunArtifact(exe_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_lib_unit_tests.step);
+    test_step.dependOn(&run_exe_unit_tests.step);
+}

build.zig.zon

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+.{
+    // This is the default name used by packages depending on this one. For
+    // example, when a user runs `zig fetch --save <url>`, 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 = "zig-argument-parser",
+
+    // 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",
+
+    // This field is optional.
+    // This is currently advisory only; Zig does not yet do anything
+    // with this value.
+    //.minimum_zig_version = "0.11.0",
+
+    // 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 <url>` 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.
+        //    .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",
+    },
+}

src/main.zig

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+const std = @import("std");
+const arguments = @import("root.zig");
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const allocator = gpa.allocator();
+
+    var first = arguments.IntArgument.init(&[_][]const u8{"first"}, &[_]u8{'f'}, 0);
+    var second = arguments.StringArgument.init(&[_][]const u8{"second"}, &[_]u8{'s'}, "");
+    var third = arguments.BoolArgument.init(&[_][]const u8{"third"}, &[_]u8{'t'});
+    var fourth = arguments.BoolArgument.init(&[_][]const u8{"fourth"}, &[_]u8{'x'});
+
+    var name = arguments.PositionalStringArgument.init("", true);
+    var age = arguments.PositionalIntArgument.init(0, true);
+    var optional = arguments.PositionalStringArgument.init("", false);
+
+    var args = [_]*arguments.Argument{ &first.arg, &second.arg, &third.arg, &fourth.arg };
+    var posArgs = [_]*arguments.PositionalArgument{ &name.arg, &age.arg, &optional.arg };
+    arguments.parse(allocator, &args, &posArgs) catch return;
+
+    if (first.found) {
+        std.debug.print("First: {}\n", .{first.value});
+    } else {
+        std.debug.print("First:\n", .{});
+    }
+    std.debug.print("Second: {s}\n", .{if (second.found) second.value else "N/A"});
+    std.debug.print("Third: {}\n", .{third.found});
+    std.debug.print("Fourth: {}\n\n", .{fourth.found});
+
+    std.debug.print("Name: {s}\n", .{name.value});
+    std.debug.print("Age: {}\n", .{age.value});
+    std.debug.print("Optional: {s}\n", .{optional.value});
+}

src/root.zig

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+const std = @import("std");
+const builtin = @import("builtin");
+const testing = std.testing;
+
+const ParseError = error{
+    UnknownArgument,
+    MissingArgumentValue,
+    MissingPositionalArgument,
+    BadPositionalArguments,
+    InvalidInteger,
+};
+
+const Parser = struct {
+    current: []const u8 = undefined,
+    isLongArg: bool = false,
+    isShortArg: bool = false,
+
+    vtable: struct {
+        next: *const fn (self: *Parser) bool,
+    },
+
+    fn next(self: *Parser) bool {
+        return self.vtable.next(self);
+    }
+
+    fn parse(self: *Parser, args: []*Argument, posArgs: []*PositionalArgument) !void {
+        if (args.len == 0 and posArgs.len == 0) {
+            return;
+        }
+
+        if (posArgs.len > 1) {
+            var i: usize = 0;
+            while (i < posArgs.len - 1) {
+                if (!posArgs[i].required and posArgs[i + 1].required) {
+                    std.debug.print("All required positional arguments must come before optional positional arguments\n", .{});
+                    return ParseError.BadPositionalArguments;
+                }
+                i += 1;
+            }
+        }
+
+        var posIndex: usize = 0;
+        while (self.next()) {
+            if (self.isLongArg) {
+                const arg = self.current;
+                self.findMatch(args, arg[2..]) catch |err| {
+                    switch (err) {
+                        ParseError.UnknownArgument => std.debug.print("Unknown argument {s}\n", .{arg}),
+                        ParseError.MissingArgumentValue => std.debug.print("Missing argument value for {s}\n", .{arg}),
+                        ParseError.InvalidInteger => std.debug.print("{s} expects an integer value, got {s} instead\n", .{ arg, self.current }),
+                        else => std.debug.print("Unexpected error occurred\n", .{}),
+                    }
+                    return err;
+                };
+            } else if (self.isShortArg) {
+                // Short argument
+                for (1..self.current.len) |i| {
+                    const arg = self.current[i];
+                    self.findShortMatches(args, arg, i == self.current.len - 1) catch |err| {
+                        switch (err) {
+                            ParseError.UnknownArgument => std.debug.print("Unknown argument -{c}\n", .{arg}),
+                            ParseError.MissingArgumentValue => std.debug.print("Missing argument value for -{c}\n", .{arg}),
+                            ParseError.InvalidInteger => std.debug.print("-{c} expects an integer value, got {s} instead\n", .{ arg, self.current }),
+                            else => std.debug.print("Unexpected error occurred\n", .{}),
+                        }
+                        return err;
+                    };
+                }
+            } else {
+                // Positional Argument
+                if (posIndex >= posArgs.len) {
+                    std.debug.print("Unknown argument {s}\n", .{self.current});
+                    return ParseError.UnknownArgument;
+                }
+
+                posArgs[posIndex].parse(self.current) catch |err| {
+                    switch (err) {
+                        ParseError.InvalidInteger => std.debug.print("Expected integer positional argument, got {s} instead\n", .{self.current}),
+                        else => std.debug.print("Unexpected error occurred\n", .{}),
+                    }
+                    return err;
+                };
+                posIndex += 1;
+            }
+        }
+
+        if (posIndex < posArgs.len and posArgs[posIndex].required) {
+            std.debug.print("Missing required positional argument\n", .{});
+            return ParseError.MissingPositionalArgument;
+        }
+    }
+
+    fn findMatch(self: *Parser, args: []*Argument, str: []const u8) !void {
+        for (args) |arg| {
+            if (arg.matches(str)) {
+                try arg.parse(self);
+                return;
+            }
+        }
+
+        return ParseError.UnknownArgument;
+    }
+
+    fn findShortMatches(self: *Parser, args: []*Argument, c: u8, last: bool) !void {
+        for (args) |arg| {
+            if (arg.shortMatches(c)) {
+                if (last) {
+                    try arg.parse(self);
+                } else {
+                    try arg.noVal();
+                    try arg.parse(self);
+                }
+                return;
+            }
+        }
+
+        return ParseError.UnknownArgument;
+    }
+};
+
+const ArgvParser = struct {
+    index: usize,
+    parser: Parser,
+
+    fn init() ArgvParser {
+        return .{
+            .index = 0,
+            .parser = .{ .vtable = .{
+                .next = ArgvParser.next,
+            } },
+        };
+    }
+
+    fn next(parser: *Parser) bool {
+        var self: *ArgvParser = @fieldParentPtr("parser", parser);
+
+        if (self.index + 1 >= std.os.argv.len) {
+            return false;
+        }
+
+        self.index += 1;
+        self.parser.current = std.mem.span(std.os.argv[self.index]);
+        self.parser.isLongArg = false;
+        self.parser.isShortArg = false;
+        if (self.parser.current.len >= 2 and self.parser.current[0] == '-') {
+            self.parser.isShortArg = self.parser.current[1] != '-';
+            if (self.parser.current.len >= 3) {
+                self.parser.isLongArg = self.parser.current[1] == '-';
+            }
+        }
+        return true;
+    }
+};
+
+const AllocParser = struct {
+    parser: Parser,
+    current: []const u8,
+    args: std.process.ArgIterator,
+
+    fn init(allocator: std.mem.Allocator) !AllocParser {
+        var self = AllocParser{
+            .args = try std.process.argsWithAllocator(allocator),
+            .current = undefined,
+            .parser = .{ .vtable = .{
+                .next = AllocParser.next,
+            } },
+        };
+
+        _ = self.args.next();
+        return self;
+    }
+
+    fn deinit(self: *AllocParser) void {
+        self.args.deinit();
+    }
+
+    fn next(parser: *Parser) bool {
+        var self: *AllocParser = @fieldParentPtr("parser", parser);
+        const val = self.args.next();
+        if (val == null) {
+            return false;
+        }
+
+        self.parser.current = val.?;
+        self.parser.isLongArg = false;
+        self.parser.isShortArg = false;
+        if (self.parser.current.len >= 2 and self.parser.current[0] == '-') {
+            self.parser.isShortArg = self.parser.current[1] != '-';
+            if (self.parser.current.len >= 3) {
+                self.parser.isLongArg = self.parser.current[1] == '-';
+            }
+        }
+        return true;
+    }
+};
+
+pub const Argument = struct {
+    names: []const []const u8,
+    shortNames: []const u8,
+
+    vtable: struct {
+        parse: *const fn (arg: *Argument, parser: *Parser) ParseError!void,
+        noVal: *const fn () ParseError!void,
+    },
+
+    fn matches(self: *Argument, arg: []const u8) bool {
+        for (self.names) |alias| {
+            if (std.mem.eql(u8, arg, alias)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    fn shortMatches(self: *Argument, arg: u8) bool {
+        for (self.shortNames) |alias| {
+            if (arg == alias) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    fn parse(self: *Argument, parser: *Parser) ParseError!void {
+        try self.vtable.parse(self, parser);
+    }
+
+    fn noVal(self: *Argument) ParseError!void {
+        return self.vtable.noVal();
+    }
+};
+
+pub const IntArgument = struct {
+    arg: Argument,
+    value: isize,
+    found: bool,
+
+    pub fn init(names: []const []const u8, shortNames: []const u8, defaultValue: isize) IntArgument {
+        return .{
+            .found = false,
+            .value = defaultValue,
+            .arg = .{ .names = names, .shortNames = shortNames, .vtable = .{ .noVal = IntArgument.noVal, .parse = IntArgument.parse } },
+        };
+    }
+
+    fn parse(arg: *Argument, parser: *Parser) ParseError!void {
+        var self: *IntArgument = @fieldParentPtr("arg", arg);
+
+        if (parser.next() and !parser.isLongArg) {
+            self.found = true;
+            self.value = std.fmt.parseInt(isize, parser.current, 0) catch {
+                return ParseError.InvalidInteger;
+            };
+        } else {
+            return ParseError.MissingArgumentValue;
+        }
+    }
+
+    fn noVal() ParseError!void {
+        return ParseError.MissingArgumentValue;
+    }
+};
+
+pub const StringArgument = struct {
+    arg: Argument,
+    value: []const u8,
+    found: bool,
+
+    pub fn init(names: []const []const u8, shortNames: []const u8, defaultVal: []const u8) StringArgument {
+        return .{
+            .found = false,
+            .value = defaultVal,
+            .arg = .{ .names = names, .shortNames = shortNames, .vtable = .{ .noVal = StringArgument.noVal, .parse = StringArgument.parse } },
+        };
+    }
+
+    fn parse(arg: *Argument, parser: *Parser) ParseError!void {
+        var self: *StringArgument = @fieldParentPtr("arg", arg);
+
+        if (parser.next() and !parser.isLongArg and !parser.isShortArg) {
+            self.found = true;
+            self.value = parser.current;
+        } else {
+            return ParseError.MissingArgumentValue;
+        }
+    }
+
+    fn noVal() ParseError!void {
+        return ParseError.MissingArgumentValue;
+    }
+};
+
+pub const BoolArgument = struct {
+    arg: Argument,
+    found: bool,
+
+    pub fn init(names: []const []const u8, shortNames: []const u8) BoolArgument {
+        return .{
+            .found = false,
+            .arg = .{ .names = names, .shortNames = shortNames, .vtable = .{ .noVal = BoolArgument.noVal, .parse = BoolArgument.parse } },
+        };
+    }
+
+    fn parse(arg: *Argument, parser: *Parser) ParseError!void {
+        _ = parser;
+
+        var self: *BoolArgument = @fieldParentPtr("arg", arg);
+        self.found = true;
+    }
+
+    fn noVal() ParseError!void {
+        return;
+    }
+};
+
+pub const PositionalArgument = struct {
+    required: bool,
+
+    vtable: struct {
+        parse: *const fn (arg: *PositionalArgument, value: []const u8) ParseError!void,
+    },
+
+    fn parse(self: *PositionalArgument, value: []const u8) ParseError!void {
+        try self.vtable.parse(self, value);
+    }
+};
+
+pub const PositionalIntArgument = struct {
+    arg: PositionalArgument,
+    value: isize,
+    found: bool,
+
+    pub fn init(defaultValue: isize, required: bool) PositionalIntArgument {
+        return .{
+            .found = false,
+            .value = defaultValue,
+            .arg = .{ .required = required, .vtable = .{ .parse = PositionalIntArgument.parse } },
+        };
+    }
+
+    fn parse(arg: *PositionalArgument, value: []const u8) ParseError!void {
+        var self: *PositionalIntArgument = @fieldParentPtr("arg", arg);
+
+        self.found = true;
+        self.value = std.fmt.parseInt(isize, value, 0) catch {
+            return ParseError.InvalidInteger;
+        };
+    }
+};
+
+pub const PositionalStringArgument = struct {
+    arg: PositionalArgument,
+    value: []const u8,
+    found: bool,
+
+    pub fn init(defaultValue: []const u8, required: bool) PositionalStringArgument {
+        return .{
+            .found = false,
+            .value = defaultValue,
+            .arg = .{ .required = required, .vtable = .{ .parse = PositionalStringArgument.parse } },
+        };
+    }
+
+    fn parse(arg: *PositionalArgument, value: []const u8) ParseError!void {
+        var self: *PositionalStringArgument = @fieldParentPtr("arg", arg);
+
+        self.found = true;
+        self.value = value;
+    }
+};
+
+pub fn parse(allocator: std.mem.Allocator, args: []*Argument, posArgs: []*PositionalArgument) !void {
+    var allocParser: AllocParser = try AllocParser.init(allocator);
+    defer allocParser.deinit();
+
+    try allocParser.parser.parse(args, posArgs);
+}
+
+pub fn parseArgv(args: []*Argument, posArgs: []*PositionalArgument) !void {
+    var argvParser: ArgvParser = ArgvParser.init();
+
+    try argvParser.parser.parse(args, posArgs);
+}
+
+test "basic add functionality" {}