example.t: Improve e macro, remove cc, eo requests

The cc and eo requests break mid-listing page breaks.

1 files changed, 63 insertions, 53 deletions

diff --git a/example.t b/example.t
index d192f86..8546f4a 100644
--- a/example.t
+++ b/example.t
@@ -1,23 +1,32 @@
 .so g.tmac
 .
-. _e p
-.  nr sq \n(sp
-.  nr sp 0
-. _e l
-.  fam M
-.  vs +1p
-._e e
-. _ec p
-. ta 3n +3n +3n +3n
-._e
-.
+.eo
 .de e
-. nr ei \\$1+1
+. if !'\$1'' \{\
+.  nr ei \$1-1
+.  af ei 0
+.  if !'\$2'' .af ei \$2
+.  ds e. .
+.  if !'\$3'' .ds e. \$3
+. \}
+. nr ei +1
 . br
 . _e e
 . ti \n(tiu
-\\n(ei.	\c
+\n(ei\*(e.	\c
 ..
+.ec
+.
+._e p
+._e l
+. fam M
+. vs +1p
+._e e
+. _ec p
+. nr sq \n(sp
+. nr sp 0
+. ta 3n +3n +3n +3n
+._e
 .
 .t
 .x Mg ,
@@ -32,7 +41,7 @@ Introduction
 .p
 .i Mg
 is a simple macro package for troff with the following features:
-.e 0
+.e 1
 It is designed to be easy to understand and to customize
 by editing the source code.
 .e
@@ -51,12 +60,25 @@ written to serve the author's personal needs.
 Users of
 .i mg
 are encouraged to
-.e 0
+.e 1 a )
 modify the source code
 according to their own needs, as well as
 .e
-use standard troff requests for some things
-that other packages provide custom macros for.
+use built-in troff requests for some things
+that other packages might provide custom macros for.
+.p
+All in all,
+.i mg
+aspires to abstract as little as possible
+from the underlying troff requests and registers.
+In its author's humble opinion,
+it is the ideal macro package for learning troff.
+.p
+In this document, the fundamental concepts of
+.i mg
+are explained.
+The reader is encouraged to inspect the document's source code
+in order to see how the macro package is used in practice.
 .
 .h
 Environments
@@ -69,26 +91,22 @@ that a macro package (and its user) would need to keep track of.
 For example,
 .i ms
 keeps track of the document's font size in the
-.i PS
+.c PS
 register.
 .i Mg ,
 on the other hand,
 simply sets the font size inside the environment named
-.i p
+.c p
 (for paragraph).
 If the user wishes to modify the default font size,
 he or she can simply switch to the
-.i p
+.c p
 environment and set the font size as desired:
 .l
-.eo
-.cc ,
-.\" set heading font
-.h
-.fam H
-.ps +1p
-,cc
-.ec
+\&.\\" set heading font
+\&.h
+\&.fam H
+\&.ps +1p
 .p
 The environments are initialized
 as soon as the first
@@ -104,18 +122,16 @@ environments.
 It is thus remarkably simple and intuitive to set,
 for example, the default font of a document:
 .l
-.cc ,
-.fam N
-.t
+\&.fam N
+\&.t
 Document title
-.p
+\&.p
 First paragraph.
-,cc
 .p
 In addition to the normal environment-relevant settings,
 .i mg
 manually associates a few special registers with the current environment:
-.e 0
+.e 1
 .c sp ,
 the amount of vertical space to add before an environment
 .e
@@ -142,12 +158,12 @@ Thanks to the reliance on environments,
 there are only two global variables
 controlling the state of
 .i mg :
-.e 0
+.e 1
 .c mt ,
-the margin at the beginning of the page
+the margin at the top of the page
 .e
 .c mb ,
-the margin at the end of the page
+the margin at the bottom of the page
 .
 .h
 External macros
@@ -172,7 +188,7 @@ the text to be formatted,
 the text to be placed immediately after
 and the text to be placed immediately before.
 The inline macros are the following:
-.e 0
+.e 1
 .c b ,
 bold font
 .e
@@ -202,7 +218,7 @@ Block-level macros
 .p
 There is a large group of macros that provide
 block-level formatting:
-.e 0
+.e 1
 .c d ,
 centered date (or given string)
 .e
@@ -229,7 +245,7 @@ Other macros
 .p
 Finally, there are a few macros
 that belong to neither category.
-.e 0
+.e 1
 .c q ,
 quotation
 .e
@@ -246,13 +262,11 @@ surrounding text in quotation marks,
 but if no arguments are given to it,
 it starts an indented block quotation instead:
 .l
-.cc ,
-.q
+\&.q
 This is an indented quotation.
-.p
+\&.p
 This is an inline
-.q quotation .
-,cc
+\&.q quotation .
 .p
 The footnote macros
 .c (
@@ -269,15 +283,11 @@ which is output immediately before or after
 the footnote number.
 .) :
 .l
-.eo
-.cc ,
-.p
-A line of text\c
-.(
+\&.p
+A line of text\\c
+\&.(
 A footnote.
-.) .
-,cc
-.ec
+\&.) .
 .p
 .i Mg
 does not account for cases where a footnote, because of its height,