v/vlib/builtin/js/builtin.v

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// Copyright (c) 2019-2022 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module builtin
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fn (a any) toString()
[noreturn]
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pub fn panic(s string) {
eprintln('V panic: $s\n$js_stacktrace()')
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exit(1)
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}
// IError holds information about an error instance
pub interface IError {
// >> Hack to allow old style custom error implementations
// TODO: remove once deprecation period for `IError` methods has ended
msg string
code int // <<
msg() string
code() int
}
pub fn (err IError) str() string {
return match err {
None__ {
'none'
}
Error {
err.msg()
}
MessageError {
err.msg()
}
else {
// >> Hack to allow old style custom error implementations
// TODO: remove once deprecation period for `IError` methods has ended
old_error_style := unsafe { voidptr(&err.msg) != voidptr(&err.code) } // if fields are not defined (new style) they don't have an offset between them
if old_error_style {
'$err.type_name(): $err.msg'
} else {
// <<
'$err.type_name(): $err.msg()'
}
}
}
}
// Error is the empty default implementation of `IError`.
pub struct Error {}
pub fn (err Error) msg() string {
return ''
}
pub fn (err Error) code() int {
return 0
}
// MessageError is the default implementation of the `IError` interface that is returned by the `error()` function
struct MessageError {
pub:
msg string
code int
}
pub fn (err MessageError) msg() string {
return err.msg
}
pub fn (err MessageError) code() int {
return err.code
}
pub const none__ = IError(&None__{})
struct None__ {
Error
}
fn (_ None__) str() string {
return 'none'
}
pub struct Option {
state byte
err IError = none__
}
pub fn (o Option) str() string {
if o.state == 0 {
return 'Option{ ok }'
}
if o.state == 1 {
return 'Option{ none }'
}
return 'Option{ error: "$o.err" }'
}
// trace_error prints to stderr a string and a backtrace of the error
fn trace_error(x string) {
eprintln('> ${@FN} | $x')
}
// error returns a default error instance containing the error given in `message`.
// Example: if ouch { return error('an error occurred') }
[inline]
pub fn error(message string) IError {
// trace_error(message)
return &MessageError{
msg: message
}
}
// error_with_code returns a default error instance containing the given `message` and error `code`.
// Example: if ouch { return error_with_code('an error occurred', 1) }
[inline]
pub fn error_with_code(message string, code int) IError {
// trace_error('$message | code: $code')
return &MessageError{
msg: message
code: code
}
}
// free allows for manually freeing memory allocated at the address `ptr`.
// However, this is a no-op on JS backend
[unsafe]
pub fn free(ptr voidptr) {
_ := ptr
}