84 lines
1.8 KiB
V
84 lines
1.8 KiB
V
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module builtin
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/*
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struct Option2<T> {
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ok bool
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is_none bool
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error string
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ecode int
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data T
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}
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*/
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// OptionBase is the the base of V's internal optional return system.
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struct OptionBase {
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ok bool
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is_none bool
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error string
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ecode int
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// Data is trailing after ecode
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// and is not included in here but in the
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// derived Option_xxx types
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}
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// `fn foo() ?Foo { return foo }` => `fn foo() ?Foo { return opt_ok(foo); }`
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fn opt_ok2(data voidptr, mut option OptionBase, size int) {
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unsafe {
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*option = OptionBase{
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ok: true
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}
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// use ecode to get the end of OptionBase and then memcpy into it
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C.memcpy(byteptr(&option.ecode) + sizeof(int), data, size)
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}
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}
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// Option is the old option type used for bootstrapping
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struct Option {
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ok bool
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is_none bool
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error string
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ecode int
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}
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// str returns the string representation of the Option.
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pub fn (o Option) str() string {
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if o.ok && !o.is_none {
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return 'Option{ ok }'
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}
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if o.is_none {
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return 'Option{ none }'
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}
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return 'Option{ error: "$o.error" }'
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}
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// opt_none is used internally when returning `none`.
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fn opt_none() Option {
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return Option{
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ok: false
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is_none: true
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}
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}
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// error returns an optional containing the error given in `message`.
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// `if ouch { return error('an error occurred') }`
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pub fn error(message string) Option {
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return Option{
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ok: false
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is_none: false
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error: message
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}
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}
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// error_with_code returns an optional containing both error `message` and error `code`.
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// `if ouch { return error_with_code('an error occurred',1) }`
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pub fn error_with_code(message string, code int) Option {
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return Option{
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ok: false
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is_none: false
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error: message
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ecode: code
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}
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}
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