[groff] 14/46: [man]: Support undocumented `mG` register.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit b7951b50439db6fea1e6af25bcb71c503bd6db4f
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Fri Dec 2 03:50:13 2022 -0600

    [man]: Support undocumented `mG` register.
    
    * tmac/an-ext.tmac: Support `mG` register: clear it to force the loading
      of this file's macros even if they have an implementation in
      tmac/an.tmac and the formatter claims groff compatibility.  This is to
      ease these macros' testing under groff and keep the implementations
      here simple.
    * tmac/an.tmac: Initialize `mG` register to 0 if not set on command
      line.
    
    ("mG" roughly means "use groff-enhanced versions of extension macros".)
---
 ChangeLog        | 10 ++++++
 tmac/an-ext.tmac |  9 ++++--
 tmac/an-tmp.tmac | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tmac/an.tmac     |  4 +++
 4 files changed, 117 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 051e3abff..bd2f5e439 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2022-12-02  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * tmac/an-ext.tmac: Support `mG` register: clear it to force the
+       loading of this file's macros even if they have an
+       implementation in tmac/an.tmac and the formatter claims groff
+       compatibility.  This is to ease these macros' testing under
+       groff and keep the implementations here simple.
+       * tmac/an.tmac: Initialize `mG` register to 1 if not set on
+       command line.
+
 2022-12-02  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * tmac/an-ext.tmac: Initialize `mX` register.
diff --git a/tmac/an-ext.tmac b/tmac/an-ext.tmac
index 533ee0176..2487e2ab4 100644
--- a/tmac/an-ext.tmac
+++ b/tmac/an-ext.tmac
@@ -207,7 +207,7 @@
 .
 .\" Set a man page cross reference.
 .\" .MR page-topic page-section [trailing-text]
-.if \n(.g .ig
+.if \n(.g-\n(mG \{\
 .de MR
 .  nh
 .  ie \\n(.$=1 \
@@ -216,6 +216,7 @@
 .    IR \\$1 (\\$2)\\$3
 .  hy \\n(mJ
 ..
+.\}
 .
 .
 .\" Continuation line for .TP header.
@@ -227,7 +228,7 @@
 .
 .
 .\" Start example.
-.if \n(.g .ig
+.if \n(.g-\n(mG \{\
 .de EX
 .  br
 .  if !\\n(mX \{\
@@ -239,10 +240,11 @@
 .    nr mX 1
 .  \}
 ..
+.\}
 .
 .
 .\" End example.
-.if \n(.g .ig
+.if \n(.g-\n(mG \{\
 .de EE
 .  br
 .  if \\n(mX \{\
@@ -252,6 +254,7 @@
 .    nr mX 0
 .  \}
 ..
+.\}
 .
 .
 .\" Start display.
diff --git a/tmac/an-tmp.tmac b/tmac/an-tmp.tmac
new file mode 100644
index 000000000..1077f7e3a
--- /dev/null
+++ b/tmac/an-tmp.tmac
@@ -0,0 +1,97 @@
+.
+.
+.\" Check if we're using grohtml or grotty, and therefore support URIs.
+.nr mH 0
+.nr mY 0
+.nr mU 0
+.if \n(.g \{\
+.  if '\*(.T'html' \
+.    nr mH 1
+.  if '\*(.T'ascii' \
+.    nr mY 1
+.  if '\*(.T'cp1047' \
+.    nr mY 1
+.  if '\*(.T'latin1' \
+.    nr mY 1
+.  if '\*(.T'utf8' \
+.    nr mY 1
+.  nr mU \n(mH+\n(mY
+.\}
+.
+.
+.\" Prepare link text for mail/web hyperlinks.  `MT` and `UR` call this.
+.de mV
+.  ds m1 \\$1\"
+.  \" Save the indentation and line length.  We want the diversion to
+.  \" format as if it has an indentation of zero (that comes for free
+.  \" when we switch environments), but we want the line length reduced
+.  \" by the amount of indentation that obtains when we output it.
+.  nr mK \\n(.l
+.  nr mI \\n(.i
+.  \" We can only hyperlink if we're not in a diversion.
+.  nr mD 0
+.  if '\\n(.z'' .nr mD 1
+.  if \\n(mD&\\nU&\\n(mU \{\
+.    \" Start diversion in a new environment.
+.    do ev link-text-env
+.    do di link-text-div
+.    ll (\\n(mKu-\\n(mIu)
+.  \}
+.  rr mI
+.  rr mK
+..
+.
+.
+.\" Emit hyperlink.  The first argument prefixes a URI scheme and colon
+.\" (e.g., "mailto:";) but since Web URLs generally supply their own,
+.\" it is not used for those (but must be present to keep the argument
+.\" count consistent).  An optional second argument supplies trailing
+.\" punctuation after link text.  `ME` and `UE` call this.
+.de mQ
+.  ds mO mailto:\";
+.  if !'\\$1'\\*(mO' \
+.    ds mO \" empty
+.
+.  ie \\n(mD&\\nU&\\n(mU \{\
+.    br
+.    di
+.    ev
+.
+.    \" Has there been at least one input line of hyperlinked text?
+.    ie \\n(dn \{\
+.      if \\n(mH \
+\X^html:<a href="\\*(mO\\*(m1">^\c
+.      if \\n(mY \
+\X^tty: link \\*(mO\\*(m1^\c
+.      \" Strip off the final newline of the diversion and emit it.
+.      do chop link-text-div
+.      do link-text-div
+\c
+.      if \\n(mH \
+\X^html:</a>^\c
+.      if \\n(mY \
+\X^tty: link^\c
+.    \}
+.    \" If there was no link text, format and link the URI.
+.    el \{\
+.      if \\n(mH \
+\X^html:<a href="\\*(mO\\*(m1">\\*(m1</a>^\c
+.      if \\n(mY \
+\X^tty: link \\*(mO\\*(m1^\\*(m1\X^tty: link^\c
+.    \}
+.    do shift
+\&\\$*\"
+.  \}
+.  \" If no link support, format URI in angle brackets.  (The link text
+.  \" was already formatted normally by `mV`.)
+.  el \{\
+.    nh
+\\*(mL\\*(m1\\*(mR\\$2
+.    do shift 2
+.    ie \n(.g .if \\n(.$ \&\\$*\"
+.    el .if \\n(.$>2 \\$3 \\$4 \\$5 \\$6 \\$7 \\$8 \\$9\"
+.    hy \\n(mJ
+.  \}
+.  rr mD
+.  rm mO
+..
diff --git a/tmac/an.tmac b/tmac/an.tmac
index 122d1db52..74397da21 100644
--- a/tmac/an.tmac
+++ b/tmac/an.tmac
@@ -1173,6 +1173,10 @@ contains unsupported escape sequence
 .  ftr CBI BI
 .\}
 .
+.\" undocumented register; unset to test an-ext.tmac extension macros
+.if !r mG \
+.  nr mG 1
+.
 .\" Load man macro extensions.
 .mso an-ext.tmac
 .