[groff] 13/15: [man]: Refactor, giving `TP` its own trap.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit ab3dce5777ed641cf5788eeaf962ed692fa25bae
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Thu Feb 1 19:35:15 2024 -0600

    [man]: Refactor, giving `TP` its own trap.
    
    * tmac/an.tmac: Refactor.  Give `TP` its own trap.
    
      (an*TP-trap): New macro takes over some of the former functions of
      `an-input-trap` and `an-write-paragraph-tag`, ending the paragraph tag
      diversion, restoring the adjustment mode and line length, and calling
      `an-write-paragraph-tag`...
    
      (an-write-paragraph-tag): ...which now deals only with formatting the
      tag.
    
      (an-input-trap): Ensure that `an*TP-trap` is sprung when input line
      traps overlap...
    
      (an-end): ...and when an ill-formed document ends with an input trap
      pending.
---
 ChangeLog    | 14 ++++++++++++++
 tmac/an.tmac | 22 ++++++++++++++++------
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 5095d2a50..4c6e8659f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2024-02-01  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * tmac/an.tmac: Refactor.  Give `TP` its own trap.
+       (an*TP-trap): New macro takes over some of the former functions
+       of `an-input-trap` and `an-write-paragraph-tag`, ending the
+       paragraph tag diversion, restoring the adjustment mode and line
+       length, and calling `an-write-paragraph-tag`...
+       (an-write-paragraph-tag): ...which now deals only with
+       formatting the tag.
+       (an-input-trap): Ensure that `an*TP-trap` is sprung when input
+       line traps overlap...
+       (an-end): ...and when an ill-formed document ends with an input
+       trap pending.
+
 2024-02-01  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * tmac/an.tmac: Refactor.
diff --git a/tmac/an.tmac b/tmac/an.tmac
index 1852f1219..e09a0d275 100644
--- a/tmac/an.tmac
+++ b/tmac/an.tmac
@@ -111,6 +111,7 @@
 .de1 an-end
 .  if !r an-TH-was-called .return
 .  an-input-trap
+.  if '\\n[.z]'an*paragraph-tag' .an*TP-trap
 .  if \\n[cR] \{\
 .    \" We might have a pending output line that is not yet broken, and
 .    \" also be 1v from the bottom of the page.  If we break (or flush)
@@ -637,10 +638,6 @@ contains unsupported escape sequence
 .\" Output the tag of a tagged paragraph, or of an indented paragraph
 .\" (IP) that has a tag.  Whether we break depends on the tag width.
 .de an-write-paragraph-tag
-.  br
-.  di
-.  ad \\*[AD]
-.  ll
 .  \" We must emit the diversion in a separate environment to ensure
 .  \" that a possible margin character is printed correctly.
 .  ev an*temporary-env
@@ -666,8 +663,8 @@ contains unsupported escape sequence
 ..
 .
 .\" Handle macros that may take an "argument" on the next input line
-.\" producing written or drawn output: .SH, .SS, .B, .I, .SM, .SB--and
-.\" .TP, which does so mandatorily.
+.\" producing written or drawn output: .SH, .SS, .B, .I, .SM, .SB.
+.\" For .TP, see below.
 .de1 an-input-trap
 .  if \\n[an-devtag-needs-end-of-heading] .DEVTAG-EO-H
 .  nr an-devtag-needs-end-of-heading 0
@@ -684,6 +681,19 @@ contains unsupported escape sequence
 .    ns
 .    nr an-need-no-space-mode 0
 .  \}
+.  \" Handle nested traps, as with
+.  \"   .TP
+.  \"   .B foo
+.  \" for instance.
+.  if '\\n[.z]'an*paragraph-tag' .an*TP-trap
+..
+.
+.\" The TP macro _requires_ a one-line input trap.
+.de1 an*TP-trap
+.  br
+.  di
+.  ad \\*[AD]
+.  ll
 .  if \\n[an*have-paragraph-tag] .an-write-paragraph-tag
 ..
 .