[ruby-core:99528] [Ruby master Bug#17110] String.tr unexpected behaviour with backslash

[ruby-core:99528] [Ruby master Bug#17110] String.tr unexpected behaviour with backslash

[entpman]

Issue #17110 has been reported by theplen (Joey Sheets).

----------------------------------------
Bug #17110: String.tr unexpected behaviour with backslash
https://bugs.ruby-lang.org/issues/17110

* Author: theplen (Joey Sheets)
* Status: Open
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x64-mingw32]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
"\\".tr("\\","A")  works great, with "\\" becoming "A"

"\\".tr("\\C","AB") should also output "A" but instead outputs "\\"




-- 
https://bugs.ruby-lang.org/

[ruby-core:99529] [Ruby master Bug#17110] String.tr unexpected behaviour with backslash

[entpman]

Issue #17110 has been updated by theplen (Joey Sheets).


``` ruby
"\\".tr("\\","A") works great, with "\\" becoming "A"

"\\".tr("\\C","AB") should also output "A" but instead outputs "\\"
```


----------------------------------------
Bug #17110: String.tr unexpected behaviour with backslash
https://bugs.ruby-lang.org/issues/17110#change-86989

* Author: theplen (Joey Sheets)
* Status: Open
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x64-mingw32]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
"\\".tr("\\","A")  works great, with "\\" becoming "A"

"\\".tr("\\C","AB") should also output "A" but instead outputs "\\"




-- 
https://bugs.ruby-lang.org/

[ruby-core:99531] [Ruby master Bug#17110] String.tr unexpected behaviour with backslash

[mame]

Issue #17110 has been updated by mame (Yusuke Endoh).

Status changed from Open to Rejected

See the document.

> The backslash character `\` can be used to escape `^` or `-` and is otherwise ignored unless it appears at the end of a range or the end of the from_str or to_str:

https://docs.ruby-lang.org/en/2.7.0/String.html#method-i-tr

So you can write `"\\".tr("C\\", "BA")` according to the document.

This seems undocumented, but `\` can be used to escape `\`, so you can also write `"\\".tr("\\\\C", "AN")`.

----------------------------------------
Bug #17110: String.tr unexpected behaviour with backslash
https://bugs.ruby-lang.org/issues/17110#change-86991

* Author: theplen (Joey Sheets)
* Status: Rejected
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x64-mingw32]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
`"\\".tr("\\","A")` works great, with `"\\"` becoming `"A"`.

`"\\".tr("\\C","AB")` should also output `"A"`, but instead outputs `"\\"`.



-- 
https://bugs.ruby-lang.org/

[ruby-core:99533] [Ruby master Bug#17110] String.tr unexpected behaviour with backslash

[entpman]

Issue #17110 has been updated by theplen (Joey Sheets).


Is there no way to do change all backslashes to forward slashes and forward slashes to backslashes in the same tr command?  

``` ruby
# Should result in "/\\" but instead results in "\\/" (unchanged)
"\\/".tr("\//","\\/")
```




----------------------------------------
Bug #17110: String.tr unexpected behaviour with backslash
https://bugs.ruby-lang.org/issues/17110#change-86993

* Author: theplen (Joey Sheets)
* Status: Rejected
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x64-mingw32]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
`"\\".tr("\\","A")` works great, with `"\\"` becoming `"A"`.

`"\\".tr("\\C","AB")` should also output `"A"`, but instead outputs `"\\"`.



-- 
https://bugs.ruby-lang.org/

[ruby-core:99535] [Ruby master Bug#17110] String.tr unexpected behaviour with backslash

[mame]

Issue #17110 has been updated by mame (Yusuke Endoh).


```
p "\\/".tr("/\\\\", "\\\\/") #=> "/\\"
```

Unfortunately it is complicated, but `\` is an escape character of string literal as well as an escape character of `String#tr` format, so it is unavoidable.

----------------------------------------
Bug #17110: String.tr unexpected behaviour with backslash
https://bugs.ruby-lang.org/issues/17110#change-86995

* Author: theplen (Joey Sheets)
* Status: Rejected
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x64-mingw32]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
`"\\".tr("\\","A")` works great, with `"\\"` becoming `"A"`.

`"\\".tr("\\C","AB")` should also output `"A"`, but instead outputs `"\\"`.



-- 
https://bugs.ruby-lang.org/

[ruby-core:99543] [Ruby master Bug#17110] String.tr unexpected behaviour with backslash

[entpman]

Issue #17110 has been updated by theplen (Joey Sheets).


Yusuke Endoh, thanks for clearing it up.

----------------------------------------
Bug #17110: String.tr unexpected behaviour with backslash
https://bugs.ruby-lang.org/issues/17110#change-87003

* Author: theplen (Joey Sheets)
* Status: Rejected
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x64-mingw32]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
`"\\".tr("\\","A")` works great, with `"\\"` becoming `"A"`.

`"\\".tr("\\C","AB")` should also output `"A"`, but instead outputs `"\\"`.



-- 
https://bugs.ruby-lang.org/