Added the Epilogue module

lang/m2/libm2/.distr

@@ -22,3 +22,4 @@ head_m2.e
 random.def
 Traps.def
 CSP.def
+Epilogue.def

lang/m2/libm2/Epilogue.def

@@ -0,0 +1,13 @@
+(*$Foreign*)
+DEFINITION MODULE Epilogue;
+(* MODULA-2 offers a facility for the initialization of modules, but there
+   is no mechanism to have some code executed when the program finishes.
+   This module is a feeble attempt at solving this problem.
+*)
+  PROCEDURE CallAtEnd(p: PROC);
+  (* Add procedure "p" to the list of procedures that must be executed when
+     the program finishes.
+     When the program finishes, these procedures are executed in the order in
+     which they were added to the list.
+  *)
+END Epilogue.

lang/m2/libm2/Makefile

@@ -5,7 +5,8 @@ SOURCES =	ASCII.def EM.def MathLib0.def Processes.def \
 		RealInOut.def Storage.def Arguments.def Conversion.def \
 		random.def Semaphores.def Unix.def RealConver.def \
 		Strings.def InOut.def Terminal.def TTY.def \
-		Mathlib.def PascalIO.def Traps.def CSP.def
+		Mathlib.def PascalIO.def Traps.def CSP.def \
+		Epilogue.def
 
 all:
 

lang/m2/libm2/catch.c

@@ -35,6 +35,7 @@ static struct errm {
 	{ M2_NORESULT,	"no RETURN from procedure function"},
 	{ M2_UOVFL,	"cardinal overflow"},
 	{ M2_FORCH,	"Warning: FOR-loop control variable was changed in the body"},
+	{ M2_ENDPROCS,	"too many procedures to be called on program termination"},
 	{ -1,		0}
 };
 

lang/m2/libm2/halt.c

@@ -1,3 +1,29 @@
+#define MAXPROCS 20
+#include <m2_traps.h>
+
+static int callindex;
+static int (*proclist[MAXPROCS])();
+
+_cleanup()
+{
+	register int i;
+
+	for (i = 0; i < callindex; i++) {
+		(*proclist[i])();
+	}
+}
+
+CallAtEnd(p)
+	int (*p)();
+{
+	if (callindex >= MAXPROCS) {
+		TRP(M2_ENDPROCS);
+	}
+	else {
+		proclist[callindex++] = p;
+	}
+}
+
 _halt()
 {
 	exit(0);

lang/m2/libm2/head_m2.e

@@ -91,6 +91,7 @@ mainroutine
  sig
  asp EM_PSIZE
  cal $_M2M
- loc 0
+ cal $_halt
+ loc 0			; should not get here
  ret EM_WSIZE
  end