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pub const core = @import("core.zig");
const builtin = @import("builtin");
const std = @import("std");
const mem = std.mem;
const fmt = std.fmt;
const debug = std.debug;
const io = std.io;
const assert = debug.assert;
pub const Param = struct {
field: []const u8,
names: core.Names,
settings: Settings,
kind: Kind,
required: bool,
position: ?usize,
pub fn flag(field: []const u8, names: *const core.Names) Param {
return init(
field,
names,
Kind.Flag,
);
}
pub fn option(
field: []const u8,
names: *const core.Names,
comptime parser: *const Parser,
) Param {
return init(
field,
names,
Kind{ .Option = parser.* },
);
}
pub fn subcommand(
field: []const u8,
names: *const core.Names,
comptime command: *const Command,
) Param {
return init(
field,
names,
Kind{ .Subcommand = command.* },
);
}
pub fn init(field: []const u8, names: *const core.Names, kind: *const Kind) Param {
return Param{
.field = field,
.names = names.*,
.kind = kind.*,
.required = false,
.position = null,
};
}
pub const Kind = union(enum) {
Flag,
Option: Parser,
Subcommand: Command,
};
};
const Opaque = @OpaqueType();
pub const Command = struct {
params: []const Param,
Result: type,
default: *const Opaque,
pub fn init(comptime Result: type, default: *const Result, params: []const Param) Command {
return Command{
.params = params,
.Result = Result,
.default = @ptrCast(*const Opaque, default),
};
}
};
pub const Parser = struct {
const UnsafeFunction = *const void;
FieldType: type,
Errors: type,
func: UnsafeFunction,
pub fn init(comptime FieldType: type, comptime Errors: type, func: ParseFunc(FieldType, Errors)) Parser {
return Parser{
.FieldType = FieldType,
.Errors = Errors,
.func = @ptrCast(UnsafeFunction, func),
};
}
fn parse(comptime parser: Parser, field_ptr: *parser.FieldType, arg: []const u8) parser.Errors!void {
return @ptrCast(ParseFunc(parser.FieldType, parser.Errors), parser.func)(field_ptr, arg);
}
fn ParseFunc(comptime FieldType: type, comptime Errors: type) type {
return fn (*FieldType, []const u8) Errors!void;
}
pub fn int(comptime Int: type, comptime radix: u8) Parser {
const func = struct {
fn i(field_ptr: *Int, arg: []const u8) !void {
field_ptr.* = try fmt.parseInt(Int, arg, radix);
}
}.i;
return Parser.init(Int, @typeOf(func).ReturnType.ErrorSet, func);
}
const string = Parser.init([]const u8, error{}, struct {
fn s(field_ptr: *[]const u8, arg: []const u8) (error{}!void) {
field_ptr.* = arg;
}
}.s);
};
pub fn Clap(comptime Result: type) type {
return struct {
const Self = this;
default: Result,
params: []const Param,
pub fn parse(
comptime clap: *const Self,
comptime Error: type,
iter: *core.ArgIterator(Error),
) !Result {
// We initialize the core.Clap without any params, and fill them out in parseHelper.
var c = core.Clap(usize, Error).init([]core.Param(usize){}, iter);
const top_level_command = comptime Command.init(Result, &clap.default, clap.params);
return try parseHelper(&top_level_command, Error, &c);
}
fn parseHelper(
comptime command: *const Command,
comptime Error: type,
clap: *core.Clap(usize, Error),
) !command.Result {
var result = @ptrCast(*const command.Result, command.default).*;
var handled = comptime blk: {
var res: [command.params.len]bool = undefined;
for (command.params) |p, i| {
res[i] = !p.settings.required;
}
break :blk res;
};
// We replace the current clap with the commands parameters, so that we preserve the that
// claps state. This is important, as core.Clap could be in a Chaining state, and
// constructing a new core.Clap would skip the last chaining arguments.
clap.params = comptime blk: {
var res: [command.params.len]core.Param(usize) = undefined;
for (command.params) |p, i| {
const id = i;
res[id] = core.Param(usize){
.id = id,
.takes_value = p.kind == Param.Kind.Option,
.names = p.names,
};
}
break :blk res;
};
var pos: usize = 0;
arg_loop: while (try clap.next()) |arg| : (pos += 1) {
inline for (command.params) |param, i| {
if (arg.param.id == i and (param.settings.position orelse pos) == pos) {
handled[i] = true;
switch (param.kind) {
Param.Kind.Flag => {
getFieldPtr(&result, param.field).* = true;
},
Param.Kind.Option => |parser| {
try parser.parse(getFieldPtr(&result, param.field), arg.value.?);
},
Param.Kind.Subcommand => |sub_command| {
getFieldPtr(&result, param.field).* = try sub_command.parseHelper(Error, clap);
// After parsing a subcommand, there should be no arguments left.
break :arg_loop;
},
}
continue :arg_loop;
}
}
return error.InvalidArgument;
}
for (handled) |h| {
if (!h)
return error.ParamNotHandled;
}
return result;
}
fn GetFieldPtrReturn(comptime Struct: type, comptime field: []const u8) type {
var inst: Struct = undefined;
const dot_index = comptime mem.indexOfScalar(u8, field, '.') orelse {
return @typeOf(&@field(inst, field));
};
return GetFieldPtrReturn(@typeOf(@field(inst, field[0..dot_index])), field[dot_index + 1 ..]);
}
fn getFieldPtr(curr: var, comptime field: []const u8) GetFieldPtrReturn(@typeOf(curr).Child, field) {
const dot_index = comptime mem.indexOfScalar(u8, field, '.') orelse {
return &@field(curr, field);
};
return getFieldPtr(&@field(curr, field[0..dot_index]), field[dot_index + 1 ..]);
}
};
}
|
