90 lines
1.9 KiB
V
90 lines
1.9 KiB
V
// Copyright (c) 2019-2021 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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// IError holds information about an error instance
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pub interface IError {
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msg string
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code int
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}
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// Error is the default implementation of IError, that is returned by e.g. `error()`
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pub struct Error {
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pub:
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msg string
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code int
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}
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pub fn (err IError) str() string {
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return match err {
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None__ { 'none' }
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Error { err.msg }
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else { '$err.type_name(): $err.msg' }
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}
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}
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const none__ = IError(&None__{})
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struct None__ {
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msg string
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code int
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}
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fn (_ None__) str() string {
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return 'none'
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}
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[if trace_error ?]
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fn trace_error(x string) {
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eprintln('> ${@FN} | $x')
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}
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// error returns a default error instance containing the error given in `message`.
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// Example: `if ouch { return error('an error occurred') }`
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[inline]
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pub fn error(message string) IError {
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trace_error(message)
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return &Error{
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msg: message
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}
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}
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// error_with_code returns a default error instance containing the given `message` and error `code`.
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// `if ouch { return error_with_code('an error occurred', 1) }`
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[inline]
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pub fn error_with_code(message string, code int) IError {
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trace_error('$message | code: $code')
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return &Error{
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msg: message
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code: code
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}
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}
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// Option is the base of V's internal optional return system.
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struct Option {
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state byte
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err IError = none__
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// Data is trailing after err
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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 opt_ok(data voidptr, mut option Option, size int) {
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unsafe {
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*option = Option{}
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// use err to get the end of OptionBase and then memcpy into it
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vmemcpy(&byte(&option.err) + sizeof(IError), data, size)
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}
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}
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[unsafe]
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pub fn (e &Error) free() {
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unsafe { e.msg.free() }
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}
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[unsafe]
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pub fn (n &None__) free() {
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unsafe { n.msg.free() }
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}
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