1 files changed, 109 insertions, 0 deletions
diff --git a/otherlibs/labltk/support/cltkVar.c b/otherlibs/labltk/support/cltkVar.c
new file mode 100644
index 0000000000..9d0f083511
--- /dev/null
+++ b/otherlibs/labltk/support/cltkVar.c
@@ -0,0 +1,109 @@
+/* Alternative to tkwait variable */
+#include <string.h>
+#include <tcl.h>
+#include <tk.h>
+#include <caml/mlvalues.h>
+#include <caml/memory.h>
+#include "camltk.h"
+
+value camltk_getvar(var) /* ML */
+     value var;
+{
+  char *s;
+  char *stable_var = NULL;
+  CheckInit();
+
+  stable_var = string_to_c(var);
+  s = Tcl_GetVar(cltclinterp,stable_var,
+		   TCL_GLOBAL_ONLY|TCL_LEAVE_ERR_MSG);
+  stat_free(stable_var);
+
+  if (s == NULL)
+    tk_error(cltclinterp->result);
+  else 
+    return(copy_string(s));
+}
+
+value camltk_setvar(var,contents) /* ML */
+     value var;
+     value contents;
+{
+  char *s;
+  char *stable_var = NULL;
+  CheckInit();
+
+  /* SetVar makes a copy of the contents. */
+  /* In case we have write traces in Caml, it's better to make sure that
+     var doesn't move... */
+  stable_var = string_to_c(var);
+  s = Tcl_SetVar(cltclinterp,stable_var, String_val(contents),
+		   TCL_GLOBAL_ONLY|TCL_LEAVE_ERR_MSG);
+  stat_free(stable_var);
+
+  if (s == NULL)
+    tk_error(cltclinterp->result);
+  else 
+    return(Val_unit);
+}
+
+
+/* The appropriate type is
+typedef char *(Tcl_VarTraceProc) _ANSI_ARGS_((ClientData clientData,
+	Tcl_Interp *interp, char *part1, char *part2, int flags));
+ */
+static char * tracevar(clientdata, interp, name1, name2, flags)
+     ClientData clientdata;
+     Tcl_Interp *interp;	/* Interpreter containing variable. */
+     char *name1;		/* Name of variable. */
+     char *name2;		/* Second part of variable name. */
+     int flags;			/* Information about what happened. */
+{
+  Tcl_UntraceVar2(interp, name1, name2,
+		TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
+		tracevar, clientdata);
+  callback2(*handler_code,Val_int(clientdata),Val_unit);
+  return (char *)NULL;
+}
+
+/* Sets up a callback upon modification of a variable */
+value camltk_trace_var(var,cbid) /* ML */
+     value var;
+     value cbid;
+{
+  char *cvar = NULL;
+
+  CheckInit();
+  /* Make a copy of var, since Tcl will modify it in place, and we
+   * don't trust that much what it will do here
+   */
+  cvar = string_to_c(var);
+  if (Tcl_TraceVar(cltclinterp, cvar,
+		   TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
+		   tracevar,
+		   (ClientData) (Long_val(cbid)))
+		   != TCL_OK) {
+    stat_free(cvar);
+    tk_error(cltclinterp->result);
+  };
+  stat_free(cvar);
+  return Val_unit;
+}
+
+value camltk_untrace_var(var,cbid) /* ML */
+     value var;
+     value cbid;
+{
+  char *cvar = NULL;
+
+  CheckInit();
+  /* Make a copy of var, since Tcl will modify it in place, and we
+   * don't trust that much what it will do here
+   */
+  cvar = string_to_c(var);
+  Tcl_UntraceVar(cltclinterp, cvar,
+		 TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
+		 tracevar,
+		 (ClientData) (Long_val(cbid)));
+  stat_free(cvar);
+  return Val_unit;
+}