From: simon <simon@cda61777-01e9-0310-a592-d414129be87e>
Date: Thu, 25 Mar 2004 19:27:12 +0000 (+0000)
Subject: Introduce \. as a NOP command. The purpose of this is to act as a
X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/halibut/commitdiff_plain/672e462641c3843b10089d25855397d1d92e4962

Introduce \. as a NOP command. The purpose of this is to act as a
zero-width delimiter between a macro invocation and text beyond it,
so that you can define (say) a macro which expands to a Euro sign
and then write `\eur\.2500' to avoid having space between the Euro
sign and the number.


git-svn-id: svn://svn.tartarus.org/sgt/halibut@3982 cda61777-01e9-0310-a592-d414129be87e
---

diff --git a/doc/input.but b/doc/input.but
index 587836f..7755d57 100644
--- a/doc/input.but
+++ b/doc/input.but
@@ -1201,8 +1201,19 @@ macro, using the \c{\\define} command:
 
 \c \define{eur} \u20AC{EUR }
 
-Then you can just write
+Then you can just write ...
 
 \c This is likely to cost \eur 2500 at least.
 
-\# FIXME: need a NOP to allow text to directly follow this. \.?
+... except that that's not terribly good, because you end up with a
+space between the Euro sign and the number. In this case, it's
+helpful to use the special \c{\\.} command, which is defined to do
+nothing at all! But it acts as a separator between your macro and
+the next character:
+
+\c This is likely to cost \eur\.2500 at least.
+
+This way, you will see no space between the Euro sign and the number
+(although, of course, there will be space between \q{EUR} and the
+number if the Euro sign is not available, because the macro
+definition specifically asked for it).
diff --git a/input.c b/input.c
index 9d165fa..95a7709 100644
--- a/input.c
+++ b/input.c
@@ -162,6 +162,7 @@ enum {
     c__invalid,			       /* invalid command */
     c__comment,			       /* comment command (\#) */
     c__escaped,			       /* escaped character */
+    c__nop,			       /* no-op */
     c__nbsp,			       /* nonbreaking space */
     c_A,			       /* appendix heading */
     c_B,			       /* bibliography entry */
@@ -231,6 +232,7 @@ static void match_kw(token *tok) {
     static const struct { char const *name; int id; } keywords[] = {
 	{"#", c__comment},	       /* comment command (\#) */
 	{"-", c__escaped},	       /* nonbreaking hyphen */
+	{".", c__nop},		       /* no-op */
 	{"A", c_A},		       /* appendix heading */
 	{"B", c_B},		       /* bibliography entry */
 	{"BR", c_BR},		       /* bibliography rewrite */
@@ -360,7 +362,7 @@ token get_token(input *in) {
     } else if (c == '\\') {	       /* tok_cmd */
 	c = get(in, &cpos);
 	if (c == '-' || c == '\\' || c == '_' ||
-	    c == '#' || c == '{' || c == '}') {
+	    c == '#' || c == '{' || c == '}' || c == '.') {
 	    /* single-char command */
 	    rdadd(&rs, c);
 	} else if (c == 'u') {
@@ -905,6 +907,11 @@ static void read_file(paragraph ***ret, input *in, indexdata *idx) {
 		break;
 	    }
 
+	    if (t.type == tok_cmd && t.cmd == c__nop) {
+		dtor(t), t = get_token(in);
+		continue;	       /* do nothing! */
+	    }
+
 	    if (t.type == tok_cmd && t.cmd == c__escaped) {
 		t.type = tok_word;     /* nice and simple */
 		t.aux = 0;	       /* even if `\-' - nonbreaking! */
diff --git a/inputs/test.but b/inputs/test.but
index 683d19b..9eb469d 100644
--- a/inputs/test.but
+++ b/inputs/test.but
@@ -25,7 +25,9 @@ a bit]
 
 \define{coopt} co\u00F6{-o}pt
 
-\versionid $Id: test.but,v 1.22 2004/03/25 19:16:28 simon Exp $
+\define{eur} \u20AC{EUR }
+
+\versionid $Id: test.but,v 1.23 2004/03/25 19:27:12 simon Exp $
 
 \C{ch\\ap} First chapter title; for similar wrapping reasons this
 chapter title will be ludicrously long. I wonder how much more
@@ -154,6 +156,8 @@ A\_paragraph\_full\_of\_nonbreaking\_spaces\_to\_test\_the\_idea\_that\_word\_wr
 Use of macros: let's talk about \coopt. And about \coopt some more.
 And a nested macro: \metacoopt.
 
+A slightly more difficult macro: \eur\.2500.
+
 Oh, while I'm here: some special characters. The \\, \{ and \}
 characters, to be precise. And their code equivalents, \c{\\},
 \i\c{\{}, \c{\}}.