Fix operator precedence according to Brian W. Kernighan and Lorinda

[mandoc.git] / roff_term.c

diff --git a/roff_term.c b/roff_term.c
index db59db08def27d49392534a8c6d608b176f1d20c..b5ec764963ea8f9e4a2576c3873143cd844c0914 100644 (file)
--- a/roff_term.c
+++ b/roff_term.c
@@ -1,4 +1,4 @@
-/*     $Id: roff_term.c,v 1.12 2017/06/14 17:51:15 schwarze Exp $ */
+/*     $Id: roff_term.c,v 1.14 2017/06/24 14:38:33 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2014, 2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
  *
@@ -19,6 +19,7 @@
 #include <assert.h>
 #include <stddef.h>
 
+#include "mandoc.h"
 #include "roff.h"
 #include "out.h"
 #include "term.h"
@@ -32,6 +33,7 @@ static        void      roff_term_pre_ce(ROFF_TERM_ARGS);
 static void      roff_term_pre_ft(ROFF_TERM_ARGS);
 static void      roff_term_pre_ll(ROFF_TERM_ARGS);
 static void      roff_term_pre_mc(ROFF_TERM_ARGS);
+static void      roff_term_pre_po(ROFF_TERM_ARGS);
 static void      roff_term_pre_sp(ROFF_TERM_ARGS);
 static void      roff_term_pre_ta(ROFF_TERM_ARGS);
 static void      roff_term_pre_ti(ROFF_TERM_ARGS);
@@ -42,6 +44,7 @@ static        const roff_term_pre_fp roff_term_pre_acts[ROFF_MAX] = {
        roff_term_pre_ft,  /* ft */
        roff_term_pre_ll,  /* ll */
        roff_term_pre_mc,  /* mc */
+       roff_term_pre_po,  /* po */
        roff_term_pre_ce,  /* rj */
        roff_term_pre_sp,  /* sp */
        roff_term_pre_ta,  /* ta */
@@ -152,6 +155,28 @@ roff_term_pre_mc(ROFF_TERM_ARGS)
                p->flags |= TERMP_ENDMC;
 }
 
+static void
+roff_term_pre_po(ROFF_TERM_ARGS)
+{
+       struct roffsu    su;
+       static int       po, polast;
+       int              ponew;
+
+       if (n->child != NULL &&
+           a2roffsu(n->child->string, &su, SCALE_EM) != NULL) {
+               ponew = term_hen(p, &su);
+               if (*n->child->string == '+' ||
+                   *n->child->string == '-')
+                       ponew += po;
+       } else
+               ponew = polast;
+       polast = po;
+       po = ponew;
+
+       ponew = po - polast + (int)p->tcol->offset;
+       p->tcol->offset = ponew > 0 ? ponew : 0;
+}
+
 static void
 roff_term_pre_sp(ROFF_TERM_ARGS)
 {