Escape 39 not processed?

[lionel-]

The quosure deparser always adds "default foreground" escape codes when printing a quosure from the global environment. This is for ease of implementation because the deparser is called recursively in case of nested quosures. It appears ansistrings does not process this escape:

str <- rlang:::quo_deparse(quo(foo))
str
#> [1] "\033[39m^foo\033[39m"

html <- ansistrings::ansi_to_html(str, FALSE)
unclass(html)
#> [1] "\033[39m^foo\033[39m"

Surprisingly it works correctly if other escapes are in the string. Here I unquote a local quosure to introduce a nested colour in the string:

str2 <- rlang:::quo_deparse(quo(foo(!!local(quo(bar)))))
str2
#> [1] "\033[39m^foo(\033[34m^bar\033[39m)\033[39m"

html2 <- ansistrings::ansi_to_html(str2, FALSE)
unclass(html2)
#> [1] "^foo(<span style=\"color:#3465a4\">^bar</span>)"

[gaborcsardi]

ansistrings currently only handled well-formed sequences, e.g. the ones generated by crayon.

[lionel-]

I cannot use crayon, do you see what's wrong in the sequence?

[gaborcsardi]

there is nothing wrong with it, just ansistrings/crayon do not use it. If it is widely implemented, then they should.

[gaborcsardi]

So, 39 is the closing "tag" in crayon, essentially. I am not sure how we could use it as an opening tag.

[lionel-]

From what I read for instance here 39 is supposed to refer to the default colour, not the last one used (which is what using it as closing tag does I presume).

[gaborcsardi]

ANSI colors do not have opening and closing tags, they just change the state. So crayon commands emulate the tags, because they are much easier to work with, they compose. E.g.:

cat(crayon::red(paste("pre", crayon::green("in"), "post")))

Without this, coloring the output would be nightmare. This is basically the single cool feature of crayon.

It would be nice to have a "default color" tag (and another one for the bg), but I am not sure if it is possible to implement that.

All this said, ansistrings should support arbitrary (even invalid) sequences.

[lionel-]

oh no worries, I'm adding escape codes "manually". I agree that crayon should be about balanced tags.

[brodieG]

FWIW, I'm pretty close to finishing fansi which should support this and unbalanced tags.

[gaborcsardi]

The problem with the manual tags is that they might not compose. E.g. if I want to include your output in a paragraph, that has a certain color (e.g. because it is in the report of a testthat test failure, so it is red), then your escape code just makes this hard.

Maybe there is a way to have a nice "default color" tag that crayon can work with. (You can still add it manually, it does not matter how it is added.) Right now, using 39 as both the start and end tag confuses crayon.

[gaborcsardi]

Btw. AFAIR @brodieG looked into this a bit, i.e. having a "default style" tag, and it was a bit cumbersome.

[brodieG]

Yeah, this is what I had looked at.