[groff] mdoc(7) .Lk: complete rewrite of the macro

[Ingo Schwarze]

Hi,

i just posted a patch containing a complete rewrite of the mdoc(7) .Lk
macro to:  https://savannah.gnu.org/bugs/index.php?52849

The point is to make it callable, get rid of the hard-to-predict
and counter-intuitive switching between in-line and display rendering,
and to make behaviour and implementation better harmonize with other
mdoc macros.  For more details and a demo input file showing the
effects, see the bug tracker.

Because of its current fragility, the macro is often used in non-
portable ways, resulting in ugly and inconsistent output.  The goal
is to make it easier to use and more robust.

I'm looking for consensus here before moving the mandoc(1)
implementation in the direction that we will agree on.
So feedback is appreciated on both the changes in functionality
and on the new implementation.

For convenience, i'm also appending the patch to this posting.

Yours,
  Ingo


--- tmac/doc.tmac-u.orig
+++ tmac/doc.tmac-u
@@ -6447,54 +6447,62 @@
 .\" NS Lk user macro
 .\" NS   link (for conversion to HTML)
 .\" NS
+.\" NS modifies:
+.\" NS   doc-arg-ptr
+.\" NS   doc-curr-font
+.\" NS   doc-curr-size
+.\" NS   doc-macro-name
+.\" NS
 .\" NS local variables:
-.\" NS   doc-delim-Lk
-.\" NS   doc-reg-Lk
+.\" NS   doc-lasttext-Lk
 .\" NS   doc-target-Lk
-.\" NS   doc-text-Lk
 .
 .de Lk
+.  if !\n[doc-arg-limit] \{\
+.    ds doc-macro-name Lk
+.    doc-parse-args \$@
+.  \}
+.
+.  if !\n[doc-arg-limit] \
+.    return
+.
 .  \" The first argument is the target URI.
-.  ds doc-target-Lk \$1
-.  shift
+.  nr doc-arg-ptr +1
+.  ds doc-target-Lk "\*[doc-arg\n[doc-arg-ptr]]
+.  nr doc-arg-ptr +1
 .
-.  \" Split the remaining arguments into link text and delimiters.
-.  ds doc-text-Lk
-.  ds doc-delim-Lk
-.  while \n[.$] \{\
-.    doc-get-width "\$1"
-.    doc-get-arg-type \$1
-.    ie (\n[doc-arg-type] > 2) \
-.      as doc-delim-Lk \$1
-.    el \{\
-.      if !'\*[doc-delim-Lk]'' \{\
-.        \" More text follows delimiter(s); go back to text mode.
-.        as doc-text-Lk \*[doc-delim-Lk]
-.        ds doc-delim-Lk
-.      \}
-.      ie '\*[doc-text-Lk]'' \
-.        ds doc-text-Lk \$1
-.      el \
-.        as doc-text-Lk " \$1
-.    \}
-.    shift
+.  \" Search backwards for the first closing punctuation.
+.  nr doc-lasttext-Lk \n[doc-arg-limit]
+.  while (\n[doc-lasttext-Lk] >= \n[doc-arg-ptr]) \{\
+.    if !(\n[doc-type\n[doc-lasttext-Lk]] == 3) \
+.      break
+.    nr doc-lasttext-Lk -1
 .  \}
 .
 .  \" Print the link text, if any.
-.  if !'\*[doc-text-Lk]'' \
-.      Em \*[doc-text-Lk] Ns :
+.  nr doc-curr-font \n[.f]
+.  nr doc-curr-size \n[.ps]
+.  if (\n[doc-arg-ptr] <= \n[doc-lasttext-Lk]) \{\
+.    nop \*[doc-Em-font]\c
+.    while (\n[doc-arg-ptr] < \n[doc-lasttext-Lk]) \{\
+.      nop \*[doc-arg\n[doc-arg-ptr]]
+.      nr doc-arg-ptr +1
+.    \}
+.    nop \*[doc-arg\n[doc-arg-ptr]]\f[\n[doc-curr-font]]\s[\n[doc-curr-size]u]:
+.    nr doc-arg-ptr +1
+.  \}
 .
 .  \" Print the link target.
-.  ie n \
-.    nr doc-reg-Lk 26
-.  el \
-.    nr doc-reg-Lk 38
-.  doc-get-width "\*[doc-target-Lk]"
-.  ie (\n[doc-width] >= \n[doc-reg-Lk]) \
-.    D1 Sy \*[doc-target-Lk] Ns \*[doc-delim-Lk]\&
-.  el .ie \n[doc-width] \
-.    Sy \*[doc-target-Lk] Ns \*[doc-delim-Lk]\&
-.  el \*[doc-delim-Lk]\&
+.  nop \*[doc-Sy-font]\*[doc-target-Lk]\c
+.  nop \f[\n[doc-curr-font]]\s[\n[doc-curr-size]u]\c
+.
+.  \" Print the delimiters, if any.
+.  while (\n[doc-arg-ptr] <= \n[doc-arg-limit]) \{\
+.    nop \*[doc-arg\n[doc-arg-ptr]]\c
+.    nr doc-arg-ptr +1
+.  \}
+.  nop \&
+.  doc-reset-args
 ..
 .
 .