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From: Kristaps Dzonsons <kristaps@bsd.lv>
To: tech@mdocml.bsd.lv
Subject: Can of worms: \h"..."
Date: Tue, 03 Jan 2012 13:19:48 +0100	[thread overview]
Message-ID: <4F02F264.2070407@bsd.lv> (raw)

[-- Attachment #1: Type: text/plain, Size: 1228 bytes --]

Hi,

On the verge of checking in a quick fix for the \h"..." TODO, it 
occurred to me that we either don't want to accomodate for pod2man 
badness OR something more subtle's at work.  \h"..." is specifically 
disallowed by groff(1).  So I searched in the groff source.  Behold!

In groff.c's input.cpp, we see several escapes (h, H, N, S, v, x) 
directly condition their enclosing markers on the first character (see 
get_delim_number()) while others do so indirectly.  These set the end 
marker on the first character given that it satisfies the 
token::delimiter() method (or whatever is C++'s name for an object 
function).

The delimiter() function (also in input.cpp) allows any character but a 
certain ASCII subset and whitespace.  groff(7) mentions the apostrophe, 
but it can much much more.

Question is: do we want this behaviour?  I'd say we do, but as it's 
somewhat intrusive, I want some consensus before committing.  Either 
way, I do NOT suggest that we outwardly document this.

Note that this also fixes the situation where some non-\N escapes were 
being assigned the NUMERIC identifier, which is only used for \N.  I 
also removed the check for \N numbers, as this is done again later.

Thoughts?

Kristaps

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Index: mandoc.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/mandoc.c,v
retrieving revision 1.62
diff -u -p -r1.62 mandoc.c
--- mandoc.c	3 Dec 2011 16:08:51 -0000	1.62
+++ mandoc.c	3 Jan 2012 12:18:51 -0000
@@ -209,9 +209,15 @@ mandoc_escape(const char **end, const ch
 		break;
 
 	/*
-	 * These escapes are of the form \X'N', where 'X' is the trigger
-	 * and 'N' resolves to a numerical expression.
+	 * These escapes accept most characters as enclosure marks
+	 * (except for those listed in the switch).
+	 * The enclosed materials are numbers, so run them through the
+	 * numerical subexpression calculator after we process.
 	 */
+	case ('N'):
+		/* Special case: numerical representation of char. */
+		gly = ESCAPE_NUMBERED;
+		/* FALLTHROUGH */
 	case ('B'):
 		/* FALLTHROUGH */
 	case ('h'):
@@ -221,7 +227,6 @@ mandoc_escape(const char **end, const ch
 	case ('L'):
 		/* FALLTHROUGH */
 	case ('l'):
-		gly = ESCAPE_NUMBERED;
 		/* FALLTHROUGH */
 	case ('S'):
 		/* FALLTHROUGH */
@@ -230,32 +235,62 @@ mandoc_escape(const char **end, const ch
 	case ('w'):
 		/* FALLTHROUGH */
 	case ('x'):
-		if (ESCAPE_ERROR == gly)
+		if (ESCAPE_NUMBERED != gly)
 			gly = ESCAPE_IGNORE;
-		if ('\'' != cp[i++])
+		numeric = term = cp[i++];
+		switch (numeric) {
+		case('0'):
+			/* FALLTHROUGH */
+		case('1'):
+			/* FALLTHROUGH */
+		case('2'):
+			/* FALLTHROUGH */
+		case('3'):
+			/* FALLTHROUGH */
+		case('4'):
+			/* FALLTHROUGH */
+		case('5'):
+			/* FALLTHROUGH */
+		case('6'):
+			/* FALLTHROUGH */
+		case('7'):
+			/* FALLTHROUGH */
+		case('8'):
+			/* FALLTHROUGH */
+		case('9'):
+			/* FALLTHROUGH */
+		case('+'):
+			/* FALLTHROUGH */
+		case('-'):
+			/* FALLTHROUGH */
+		case('/'):
+			/* FALLTHROUGH */
+		case('*'):
+			/* FALLTHROUGH */
+		case('%'):
+			/* FALLTHROUGH */
+		case('<'):
+			/* FALLTHROUGH */
+		case('>'):
+			/* FALLTHROUGH */
+		case('='):
+			/* FALLTHROUGH */
+		case('&'):
+			/* FALLTHROUGH */
+		case(':'):
+			/* FALLTHROUGH */
+		case('('):
+			/* FALLTHROUGH */
+		case(')'):
+			/* FALLTHROUGH */
+		case('.'):
 			return(ESCAPE_ERROR);
-		term = numeric = '\'';
-		break;
-
-	/*
-	 * Special handling for the numbered character escape.
-	 * XXX Do any other escapes need similar handling?
-	 */
-	case ('N'):
-		if ('\0' == cp[i])
+		default:
+			break;
+		}
+		if (isspace((unsigned char)numeric))
 			return(ESCAPE_ERROR);
-		*end = &cp[++i];
-		if (isdigit((unsigned char)cp[i-1]))
-			return(ESCAPE_IGNORE);
-		while (isdigit((unsigned char)**end))
-			(*end)++;
-		if (start)
-			*start = &cp[i];
-		if (sz)
-			*sz = *end - &cp[i];
-		if ('\0' != **end)
-			(*end)++;
-		return(ESCAPE_NUMBERED);
+		break;
 
 	/* 
 	 * Sizes get a special category of their own.

             reply	other threads:[~2012-01-03 12:19 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-03 12:19 Kristaps Dzonsons [this message]
2012-01-04  0:54 ` Ingo Schwarze

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