Add styledWrite macro

[kaushalmodi]

Also:

• Move the tests block to the end of the file
• Fix the older tests
• Convert styledEcho from a macro to a template, add tests for that.
• Convert styledWriteLine from a macro to a template, add more tests for that.
• Add new tests for styledWrite

Fixes #8046.

---

This commit works, but I don't understand the macro syntax, and would like styledWriteLine to reuse styledWrite that I added.

Let me know if that optimization needs to be made before this can be committed.. or if someone can optimize that after this gets committed.

Also, need to fix these warnings:

terminal.nim(706, 11) Warning: use varargs[untyped] in the macro prototype instead; callsite is deprecated [Deprecated]
terminal.nim(740, 11) Warning: use varargs[untyped] in the macro prototype instead; callsite is deprecated [Deprecated]

Thanks!

[kaushalmodi]

This was my naive approach for refactoring styledWriteLine, so it of course doesn't work..

macro styledWriteLine*(f: File, args: varargs[typed]): untyped =
  ## Similar to ``writeLine``, but treating terminal style arguments specially.
  ## When some argument is ``Style``, ``set[Style]``, ``ForegroundColor``,
  ## ``BackgroundColor`` or ``TerminalCmd`` then it is not sent directly to
  ## ``f``, but instead corresponding terminal style proc is called.
  ##
  ## Example:
  ##
  ## .. code-block:: nim
  ##
  ##   proc error(msg: string) =
  ##     styledWriteLine(stderr, fgRed, "Error: ", resetStyle, msg)
  ##
  result = newCall(bindSym"styledWrite")
  result.add(f)
  for arg in children(args):
    result.add(arg)
  result.add(newCall(bindSym"write", f, newStrLitNode("\n")))

[Vindaar]

You can fix the refactored approach like so:

macro styledWriteLine*(f: File, args: varargs[typed]): untyped =
  # result should be a statement list
  result = newStmtList()
  # create new call with `f` as first argument
  result.add newCall(bindSym"styledWrite", f) 
  for arg in children(args):
    # append all arguments to the `nnkCall` node
    result[^1].add(arg)

  result.add(newCall(bindSym"write", f, newStrLitNode("\n")))

[kaushalmodi]

@Vindaar Actually I just converted the 2 unnecessary? macros to templates.. can you check this PR in entirety?

/cc @krux02

[kaushalmodi]

Earlier when styledWriteLine was a macro, below:

stdout.styledWriteLine(fgRed, "red text ")
stdout.styledWriteLine(fgWhite, bgRed, "white text in red background")
stdout.styledWriteLine(" ordinary text ")
stdout.styledWriteLine(fgGreen, "green text")

resulted in:

(Above the underlined "styled text" was blinking and so wasn't caught in that screenshot :))

Now the same test, with styledWriteLine now being a template, and the newline added after the resetAttributes call in styleWrite, results in this:

[kaushalmodi]

Except for the "callsite is deprecated" warning that was already there, I am happy with this PR now.

Would be great if someone can review this further.

[krux02]

just my two cents for the example, you changed stderr.styledWrite to stdout.styledWrite. There is a convention in unix systems, that output on stdout can be further processed by another application if you pipe it into that program, and stderr the actual text the user is supposed to see. processed text in other appications should better not have colors in them. So I prefer if the example of styleWrite remains on stderr. Apart from that I think it's ok.

[kaushalmodi]

you changed stderr.styledWrite to stdout.styledWrite

So I prefer if the example of styleWrite remains on stderr.

Just to clarify, the styledWrite wasn't there at all to begin with. It was added in this PR.

As styledWriteLine had an stderr example, I decided to throw in a variety and set the new styledWrite example to have stdout.

There is a convention in unix systems, that output on stdout can be further processed by another application if you pipe it into that program, and stderr the actual text the user is supposed to see.

I completely agree with that. But this example is just about displaying colorful text on stdout.

processed text in other appications should better not have colors in them.

I believe, the application developer should consciously prevent adding colors based on terminal.isatty? (my related blog on that)

[krux02]

I mean there are things that are obviously still wrong, but they have never been in a better state either. When two threads call styledWriteLine at the same time, the lines can be interleaved. With for example printf, this can't happen. Neither can it happen with echo afaik.

[dom96]

Looks good :)