What's the purpose of the grave accent ` in failure messages?

[NorseGaud]

Been there from day one: sstephenson/bats@c850527#diff-2285302ec7310b89fd9edfef3694598bebfa056fdbfd7e5d607026f64a68d734R80

It seems to work just fine when changing it to ' instead. I'd like to open this to discuss what potential downfalls there are of removing it.

[NorseGaud]

It makes bash code blocks really ugly:

[martin-schulze-vireso]

I think this is a more or less historc typographic gimmick https://en.wikipedia.org/wiki/Quotation_mark#Typewriters_and_early_computers. With regard to your example it might be better to use ` also for closing the command, which should fix the parsing and maybe enable syntax highlighting.

[NorseGaud]

@martin-schulze-vireso , so would you favor a PR for ending with ` or simply removing ` altogether?

[martin-schulze-vireso]

It really depends on the context. Could you try what the fully `` wrapped version looks like in the environment you showed above?

[NorseGaud]

❯ bin/bats --filter "^extended syntax" test/bats.bats
 ✓ extended syntax

1 test, 0 failures

❯ BATS_TRACE_LEVEL=1 bin/bats --filter "^extended syntax" test/bats.bats
 ✗ extended syntax
   (in test file test/bats.bats, line 329)
     `[ "${lines[7]}" = 'ok 2 a passing test' ]` failed
   + bats-exec-suite -x /Users/norsegaud/bats-core/test/fixtures/bats/failing_and_passing.bats

❯ BATS_TRACE_LEVEL=2 bin/bats --filter "^extended syntax" test/bats.bats
 ✗ extended syntax
   (in test file test/bats.bats, line 329)
     `[ "${lines[7]}" = 'ok 2 a passing test' ]` failed
   + bats-exec-suite -x /Users/norsegaud/bats-core/test/fixtures/bats/failing_and_passing.bats
   1..2
   suite /Users/norsegaud/bats-core/test/fixtures/bats/failing_and_passing.bats
   begin 1 a failing test
   not ok 1 a failing test
   # (in test file test/fixtures/bats/failing_and_passing.bats, line 2)
   #   `false' failed
   begin 2 a passing test
      
   ok 2 a passing test

1 test, 1 failure

Is this what you mean? So we'd instead potentially change it to end in ` too? I think that looks pretty good, if not better than ' ' wrapping.

[martin-schulze-vireso]

No, I meant the environment from the screenshot above. I'd like to see if it fixes the highlighting.

[jasonkarns]

I'd like to dig more into the rationale for it existing in the first place, before we change it. I've seen this pattern frequently enough in other heavily used shell scripts and tools that I don't believe it was accidental.

[NorseGaud]

https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xcu_chap02.html#tag_23_02_06_03

Some implementations have allowed the end of the word to terminate the backquoted command substitution, such as in:
"`echo hello"

[NorseGaud]

https://unix.stackexchange.com/questions/121927/why-bash-encapsulates-syntax-error-both-with-grave-accent-and-with-an-apostrophe

In certain fonts, those quotation marks will appear as opposing pairs of curled single quotes. It's passé in today's Unicode world, but the code and practices that produced such quoting derive from a time before Unicode, or before its widespread availability.

https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html

Summary: Please do not use the ASCII grave accent (0x60) as a left quotation mark together with the ASCII apostrophe (0x27) as the corresponding right quotation mark (as in `quote'). Your text will otherwise appear rather strange with most modern fonts (e.g., on Windows and Mac systems). Only old X Window System fonts and some old video terminals show ASCII 0x60/0x27 as left and right quotation marks, while most modern systems follow the ISO and Unicode standards instead. If you can use only ASCII’s typewriter characters, then use the apostrophe character (0x27) as both the left and right quotation mark (as in 'quote'). If you can use Unicode characters, nice directional quotation marks are available in the form of characters U+2018, U+2019, U+201C, and U+201D (as in ‘quote’ or “quote”).

if displayed with old X fonts, but it looked rather ugly like
`quotation'

If you are the author of some Unix software, then please check, whether you use the ASCII character 0x60 (`) as a left quotation mark as in `quote'. Change it such that you use instead the character 0x27 (') on both sides, as in 'quote'. If you work in an environment where the UTF-8 encoding is already used everywhere (e.g., Plan9 and most modern GNU/Linux installations), you could even decide to use proper directional quotation marks, as in ‘quote’ or “quote”.

This seems to be a remnant from the past.

[martin-schulze-vireso]

@jasonkarns

I'd like to dig more into the rationale for it existing in the first place, before we change it. I've seen this pattern frequently enough in other heavily used shell scripts and tools that I don't believe it was accidental.

I think this thread established well enough that it is a typographic hack for older, non utf systems. Maybe we can offer configuration variables that allow users to decide on the delimiters?

[shadowspawn]

For interest, Commander had a similar request to change the quotes used in error messages. After some research we accepted the change. My conclusion was it was a dated convention, and I referenced one of same links as #470 (comment)

tj/commander.js#915