Re: "trap ... DEBUG" to execute before (instead of after) each

[Peter Stephenson <p.w.stephenson@ntlworld.com>]

On Thu, 11 Jan 2007 22:32:33 +0000
Peter Stephenson <p.w.stephenson@ntlworld.com> wrote:
> nwsgpamachine@alcatel-lucent.com wrote:
> > Dear Peter,
> > !! The BIG problem is that the patched version does not report 
> > !! LINENO values correctly. 
> 
> Yes, I forgot about the line number stuff which isn't particularly well
> implemented at the moment.

I think the following (relatively straightforward) change should do the
trick.  The reason I think it's OK is that it sets up the line number
right at the start of each top-level chunk of code, so it should cover
all possible cases.  The line number is still updated for each pipeline,
which is what you'd see if you were doing debugging at a lower level (or
printing the line number).  The difference is that code like "foo &&
bar" only invokes the DEBUG trap once, but updates the line number for
both "foo" and "bar".

There may be other simplifications or rearrangements but I couldn't see
anything crying out to be changed.

The zsh.h changes are simply making definitions clearer; there's no
functional change, and hence no incompatibility in compiled wordcode.

Please let me know if you notice any more line numbering
oddities... there have been a number over the years and it looks like
you're in a good position to notice them.

Index: Src/exec.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/exec.c,v
retrieving revision 1.108
diff -u -r1.108 exec.c
--- Src/exec.c	9 Jan 2007 21:59:31 -0000	1.108
+++ Src/exec.c	14 Jan 2007 19:01:12 -0000
@@ -866,6 +866,35 @@
     code = *state->pc++;
     while (wc_code(code) == WC_LIST && !breaks && !retflag) {
 	int donedebug;
+
+	ltype = WC_LIST_TYPE(code);
+	csp = cmdsp;
+
+	if ((!intrap || trapisfunc) && !ineval) {
+	    /*
+	     * Ensure we have a valid line number for debugging,
+	     * unless we are in an evaluated trap in which case
+	     * we retain the line number from the context.
+	     * This was added for DEBUGBEFORECMD but I've made
+	     * it unconditional to keep dependencies to a minimum.
+	     *
+	     * The line number is updated for individual pipelines.
+	     * This isn't necessary for debug traps since they only
+	     * run once per sublist.
+	     */
+	    wordcode code2 = *state->pc, lnp1 = 0;
+	    if (ltype & Z_SIMPLE) {
+		lnp1 = code2;
+	    } else if (wc_code(code2) == WC_SUBLIST) {
+		if (WC_SUBLIST_FLAGS(code2) == WC_SUBLIST_SIMPLE)
+		    lnp1 = state->pc[2];
+		else
+		    lnp1 = WC_PIPE_LINENO(state->pc[1]);
+	    }
+	    if (lnp1)
+		lineno = lnp1 - 1;
+	}
+
 	if (sigtrapped[SIGDEBUG] && isset(DEBUGBEFORECMD)) {
 	    exiting = donetrap;
 	    ret = lastval;
@@ -881,9 +910,6 @@
 	} else
 	    donedebug = 0;
 
-	ltype = WC_LIST_TYPE(code);
-	csp = cmdsp;
-
 	if (ltype & Z_SIMPLE) {
 	    next = state->pc + WC_LIST_SKIP(code);
 	    execsimple(state);
Index: Src/zsh.h
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/zsh.h,v
retrieving revision 1.107
diff -u -r1.107 zsh.h
--- Src/zsh.h	9 Jan 2007 21:59:31 -0000	1.107
+++ Src/zsh.h	14 Jan 2007 19:01:14 -0000
@@ -703,8 +703,9 @@
 #define WC_LIST_TYPE(C)     wc_data(C)
 #define Z_END               (1<<4) 
 #define Z_SIMPLE            (1<<5)
-#define WC_LIST_SKIP(C)     (wc_data(C) >> 6)
-#define WCB_LIST(T,O)       wc_bld(WC_LIST, ((T) | ((O) << 6)))
+#define WC_LIST_FREE        (6)	/* Next bit available in integer */
+#define WC_LIST_SKIP(C)     (wc_data(C) >> WC_LIST_FREE)
+#define WCB_LIST(T,O)       wc_bld(WC_LIST, ((T) | ((O) << WC_LIST_FREE)))
 
 #define WC_SUBLIST_TYPE(C)  (wc_data(C) & ((wordcode) 3))
 #define WC_SUBLIST_END      0
@@ -714,8 +715,10 @@
 #define WC_SUBLIST_COPROC   4
 #define WC_SUBLIST_NOT      8
 #define WC_SUBLIST_SIMPLE  16
-#define WC_SUBLIST_SKIP(C)  (wc_data(C) >> 5)
-#define WCB_SUBLIST(T,F,O)  wc_bld(WC_SUBLIST, ((T) | (F) | ((O) << 5)))
+#define WC_SUBLIST_FREE    (5)	/* Next bit available in integer */
+#define WC_SUBLIST_SKIP(C)  (wc_data(C) >> WC_SUBLIST_FREE)
+#define WCB_SUBLIST(T,F,O)  wc_bld(WC_SUBLIST, \
+				   ((T) | (F) | ((O) << WC_SUBLIST_FREE)))
 
 #define WC_PIPE_TYPE(C)     (wc_data(C) & ((wordcode) 1))
 #define WC_PIPE_END         0


-- 
Peter Stephenson <p.w.stephenson@ntlworld.com>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/