Scanner (?), broken escape sequence detection

[Bruno-Vdr]

Describe the bug

It looks like there is a problem when parsing escaped single quote within string interpolation in the scanner (Spytheman's hypothesis).

Reproduction Steps

module main

import term

fn main() {
	println('Hey it\'s ${term.blue('Tony\'s')} car !')
}

Expected Behavior

Fine compilation.

Current Behavior

main.v:8:1: error: unfinished string literal
    6 |     println('Hey it\'s ${term.blue('Tony\'s')} car !')
    7 | }

Possible Solution

Using a local variable.

		str := 'Tony\'s'
		println('Hey it\'s ${term.blue(str)} car !')

Additional Information/Context

Spytheman also add (Note double quotes):
https://discord.com/channels/592103645835821068/592294828432424960/1360579781992644700

module main

import term

fn main() {
	println('Hey it\'s ${term.blue("Tony\'s")} car !')
}

also work, but vfmt tool will replace double quotes by single, and next compilation will fail.

V version

V 0.4.10 c2e27ef

Environment details (OS name and version, etc.)

Debian linux testing (trixie)

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[jorgeluismireles]

As you said, vfmt is having problems since working println('Hey it\'s ${term.blue("Tony\'s")} car !') is changed and then don't compile. Imho is not worth abusing extrapolation, this is more readable and mantainable later:

str := term.blue("Tony's")
println('Hey it\'s ${str} car !')

[Bruno-Vdr]

I understand your point of view, but disagree here. I think we need to know if this code is allowed or not, even if it's less readable. The answer 'Yes but ... or Not but...' is not acceptable for me. If V's grammar allows this statement, it should be accepted.

[1ethanhansen]

I get the same error but not for escaped single quotes, but for non-curly-brace-enclosed string interpolations. Here is an example: line 196 works like this but not if it's println('updated to $new_season'). In that case, I get this error:

➜  Vetero git:(main) ✗ v run vet.v
vet.v:563:1: error: unfinished string literal
  561 |     return ctx.json(history_summary)
  562 | }
Details: 
vet.v:543:62: details: literal started here
  541 |     settings_id := ctx.query['settings_id'] or {
  542 |         ctx.res.set_status(.bad_request)
  543 |         return ctx.request_error('You have to supply a settings_id!')
      |                                                                    ^
  544 |     }.int()
  545 |

And the same thing if I do v fmt.

I might be able to help solve this bug. I should look in https://github.com/vlang/v/blob/master/vlib/v/scanner/scanner.v right?

[Delta456]

Yes

[fleximus]

For anyone running into this, a temporary workaround could be using string concatenation, for instance:

module main

import term

fn main() {
	println("Hey it's " + term.blue("Tony's") + " car !")
}