Workaround to issue #1129. TODO: error trapping in user contributed functions.

stack/maxima/contrib/vectorcalculus.mac

@@ -24,7 +24,7 @@
 /* Calculate the divergence of a vector-valued function         */
 /****************************************************************/
 div(u, vars):= block([div_vec],
-    if not(listp(vars)) or emptyp(vars) then error("div: the second argument must be a list of variables."),
+    /* TODO: error trapping: if not(listp(vars)) or emptyp(vars) then error("div: the second argument must be a list of variables."), */
     if matrixp(u) then funcs: list_matrix_entries(u) else funcs: flatten(u),
     /* TODO: confirm div should always simplify? */
     div_vec: map(lambda([ex], ev(diff(funcs[ex],vars[ex]), simp)), ev(makelist(ii,ii,1,length(vars)), simp)),
@@ -39,7 +39,7 @@ s_test_case(div(matrix([x^2*cos(y),y^3]),[x,y]), 2*x*cos(y)+3*y^2);
 /* Calculate the curl of a vector-valued function               */
 /****************************************************************/
 curl(u,vars):= block([cux, cuy, cuz],
-    if not(listp(vars)) or emptyp(vars) then error("curl: the second argument must be a list of 3 variables."),
+    /* TODO: error trapping: if not(listp(vars)) or emptyp(vars) then error("curl: the second argument must be a list of 3 variables."), */
     if matrixp(u) then [ux,uy,uz]: list_matrix_entries(u) else [ux,uy,uz]: flatten(u),
     cux: diff(uz,vars[2]) - diff(uy,vars[3]),
     cuy: diff(ux,vars[3]) - diff(uz,vars[1]),