only attach ojs_define etc if needed.

[cscheid]

(cc @jennybc)

This PR makes it so that search() doesn't get polluted by the tools:quarto attach() call, which is really only needed on OJS settings.

[cderv]

Small comment on the regex.

Otherwise, regarding the duplication, I think attach() is used to put in search path what they call a database. So when you call it twice with same name, it will add a new one and not assign the what value to it.

You need to use assign() for that.

So you could do

• .tools_env <- attach(NULL, name = "tools:quarto") to create the environment. This is mentioned in the help page

  One useful ‘trick’ is to use what = NULL (or equivalently a length-zero list) to create a new environment on the search path into which objects can be assigned by assign()

• Then use assign(..., envir = .tools_env) when you need to add to that one

This is how I would do it.

As I remembered RStudio IDE is also using a tools:rstudio, I checked and they are doing this kind of things, with more complex tricks for some reason (using a function to get the environment as an environment if it already exists, I don't think we need that).
Anyhow, you can see here
https://github.com/rstudio/rstudio/blob/68c31072ae07761aab3747ead8044b729cfe9cb4/src/cpp/r/R/Tools.R#L16-L22

Hope it helps

[cderv]

FWIW this is the pattern we use in knitr to detect chunks
https://github.com/yihui/knitr/blob/1239f36c5dee8b0e029958a793ae71558902f52c/R/pattern.R#L32

^[\t >]*```+\\s*\\{([a-zA-Z0-9_]+( *[ ,].*)?)\\}\\s*$

A bit more complex regex but I think this is because it covers more case in knitr; like options in chunk header and we match on line. So seems good.

Only two comments on the pattern:

• I think [[:space:]] covers new line so you don't need \n before.
• Are we really strict on {ojs} exactly ? Nothing else can be in the { } ? We support a bit more in knitr
  • for example I think a space works currently like ```{ojs } works
  • Could there be any options ?

Just sharing as this could breaks some usage (that we could see as bad syntax, but it works today)

This could mean using \\{ojs( *)?\\} or \\{ojs[^}]*\\}

[cscheid]

This could mean using \\{ojs( *)?\\} or \\{ojs[^}]*\\}

Either one of these is better than what I have, you're totally right.

[cscheid]

So you could do

• .tools_env <- attach(NULL, name = "tools:quarto") to create the environment. This is mentioned in the help page

  One useful ‘trick’ is to use what = NULL (or equivalently a length-zero list) to create a new environment on the search path into which objects can be assigned by assign()

• Then use assign(..., envir = .tools_env) when you need to add to that one

This is how I would do it.

Yes, I agree that this is how we should do that. My first goal was to hide them at all because Jenny needed a clean search() result for the book she's writing.

The reason I didn't do it right away is that the two calls to attach happen in separate files, and I don't know the semantics of source() well enough to understand what happens with the variable assignment and the associated scope. But I'd appreciate the help in fixing that!