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From: Ingo Schwarze <schwarze@usta.de>
To: "Anthony J. Bentley" <anthony@anjbe.name>
Cc: tech@mandoc.bsd.lv
Subject: Re: eqn(7): Precedence of from/to/sub/sup
Date: Thu, 6 Jul 2017 02:26:41 +0200	[thread overview]
Message-ID: <20170706002640.GG88736@athene.usta.de> (raw)
In-Reply-To: <14094.1499140567@cathet.us>

Hi Anthony,

Anthony J. Bentley wrote on Mon, Jul 03, 2017 at 09:56:07PM -0600:

> Kernighan & Cherry's "Typesetting Mathematics: User's Guide" (2e) says:
> 
>     If you don't use braces, eqn(1) will do operations in the order
>     shown in this list.
> 
>     dyad vec under bar tilde hat dot dotdot
>     fwd back down up
>     fat roman italic bold size
>     sub sup sqrt over
>     from to

Good point, fixed by the commit below.

If you still see errors, don't hesitate to tell me.

Thanks,
  Ingo


Log Message:
-----------
Fix operator precedence according to Brian W. Kernighan and Lorinda
L. Cherry, "Typesetting Mathematics - User's Guide (Second Edition)",
August 15, 1978, paragraph 23; swarm of bugs pointed out by bentley@.

Modified Files:
--------------
    mandoc:
        eqn.c
        eqn_term.c
    mandoc/regress/eqn/fromto:
        Makefile
    mandoc/regress/eqn/over:
        precedence.in
        precedence.out_ascii
        precedence.out_html
    mandoc/regress/eqn/subsup:
        Makefile
    mandoc/regress/eqn/unary:
        bold.in
        bold.out_ascii
        bold.out_html
        diacrit.in
        diacrit.out_ascii
        diacrit.out_html
        sqrt.in
        sqrt.out_ascii
        sqrt.out_html

Added Files:
-----------
    mandoc/regress/eqn/fromto:
        precedence.in
        precedence.out_ascii
        precedence.out_html
    mandoc/regress/eqn/subsup:
        precedence.in
        precedence.out_ascii
        precedence.out_html

Revision Data
-------------
Index: eqn_term.c
===================================================================
RCS file: /home/cvs/mandoc/mandoc/eqn_term.c,v
retrieving revision 1.10
retrieving revision 1.11
diff -Leqn_term.c -Leqn_term.c -u -p -r1.10 -r1.11
--- eqn_term.c
+++ eqn_term.c
@@ -113,15 +113,6 @@ eqn_box(struct termp *p, const struct eq
 
 	if (bp->font != EQNFONT_NONE)
 		term_fontpop(p);
-	if ((bp->type == EQN_LIST && bp->expectargs > 1) ||
-	    (bp->type == EQN_PILE && (bp->prev || bp->next)) ||
-	    (bp->parent != NULL && bp->parent->pos == EQNPOS_SQRT)) {
-		p->flags |= TERMP_NOSPACE;
-		term_word(p, bp->right != NULL ? bp->right : ")");
-		if (bp->parent->type == EQN_SUBEXPR && bp->next != NULL)
-			p->flags |= TERMP_NOSPACE;
-	}
-
 	if (bp->top != NULL) {
 		p->flags |= TERMP_NOSPACE;
 		term_word(p, bp->top);
@@ -129,5 +120,13 @@ eqn_box(struct termp *p, const struct eq
 	if (bp->bottom != NULL) {
 		p->flags |= TERMP_NOSPACE;
 		term_word(p, "_");
+	}
+	if ((bp->type == EQN_LIST && bp->expectargs > 1) ||
+	    (bp->type == EQN_PILE && (bp->prev || bp->next)) ||
+	    (bp->parent != NULL && bp->parent->pos == EQNPOS_SQRT)) {
+		p->flags |= TERMP_NOSPACE;
+		term_word(p, bp->right != NULL ? bp->right : ")");
+		if (bp->parent->type == EQN_SUBEXPR && bp->next != NULL)
+			p->flags |= TERMP_NOSPACE;
 	}
 }
Index: eqn.c
===================================================================
RCS file: /home/cvs/mandoc/mandoc/eqn.c,v
retrieving revision 1.73
retrieving revision 1.74
diff -Leqn.c -Leqn.c -u -p -r1.73 -r1.74
--- eqn.c
+++ eqn.c
@@ -819,6 +819,8 @@ next_tok:
 			ep->gsize = size;
 			break;
 		}
+		while (parent->args == parent->expectargs)
+			parent = parent->parent;
 		parent = eqn_box_alloc(ep, parent);
 		parent->type = EQN_LIST;
 		parent->expectargs = 1;
@@ -840,13 +842,25 @@ next_tok:
 			cur->type = EQN_TEXT;
 			cur->text = mandoc_strdup("");
 		}
-		/* Handle the "subsup" and "fromto" positions. */
-		if (EQN_TOK_SUP == tok && parent->pos == EQNPOS_SUB) {
+		while (parent->expectargs == 1 && parent->args == 1)
+			parent = parent->parent;
+		if (tok == EQN_TOK_FROM || tok == EQN_TOK_TO)  {
+			for (cur = parent; cur != NULL; cur = cur->parent)
+				if (cur->pos == EQNPOS_SUB ||
+				    cur->pos == EQNPOS_SUP ||
+				    cur->pos == EQNPOS_SUBSUP ||
+				    cur->pos == EQNPOS_SQRT ||
+				    cur->pos == EQNPOS_OVER)
+					break;
+			if (cur != NULL)
+				parent = cur->parent;
+		}
+		if (tok == EQN_TOK_SUP && parent->pos == EQNPOS_SUB) {
 			parent->expectargs = 3;
 			parent->pos = EQNPOS_SUBSUP;
 			break;
 		}
-		if (EQN_TOK_TO == tok && parent->pos == EQNPOS_FROM) {
+		if (tok == EQN_TOK_TO && parent->pos == EQNPOS_FROM) {
 			parent->expectargs = 3;
 			parent->pos = EQNPOS_FROMTO;
 			break;
@@ -895,6 +909,8 @@ next_tok:
 			cur->type = EQN_TEXT;
 			cur->text = mandoc_strdup("");
 		}
+		while (parent->args == parent->expectargs)
+			parent = parent->parent;
 		while (EQN_SUBEXPR == parent->type)
 			parent = parent->parent;
 		parent = eqn_box_makebinary(ep, EQNPOS_OVER, parent);
@@ -1099,13 +1115,6 @@ next_tok:
 				parent = split->parent;
 			break;
 		}
-		/*
-		 * Post-process list status.
-		 */
-		while (parent->type == EQN_LIST &&
-		    parent->expectargs == 1 &&
-		    parent->args == 1)
-			parent = parent->parent;
 		break;
 	default:
 		abort();
--
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      reply	other threads:[~2017-07-06  0:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-04  3:56 Anthony J. Bentley
2017-07-06  0:26 ` Ingo Schwarze [this message]

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