The Bracket command brackets a verification, ver, by converting it to a verification suitable for testing the content of an addressable structure that has been wrapped in list brackets.

Bracket(ver) expands dummy verifications %NULL, seq, and &, in ver, as explained on verify,exprseq.

%NULL verifies empty expression sequences.

seq(ver) verifies expression sequences of ver verifications.

(ver1 &, ver2 &, ver3 ... ) verifies expression sequences using ver1 for the first element, etc.

This procedure is used by the verifications Array, Matrix, Vector, rtable, record, and table, when an optional verification is specified.

$\mathrm{with}\left(\mathrm{VerifyTools}\right)\:$

$v≔\mathrm{Vector}\left(2\right)\:$

$v\left[1\right]≔1,\left[2\,6\,4\right]\:$

$v\left[2\right]≔\mathrm{NULL}\:$

$w≔\mathrm{Vector}\left(2\right)\:$

$w\left[1\right]≔1,\left[2\,4\,4\,6\right]\:$

$w\left[2\right]≔\mathrm{NULL}\:$

$v,w$

$\left[\begin{array}{c}1,\left[2\,6\,4\right]\\ \left(\right)\end{array}\right],\left[\begin{array}{c}1,\left[2\,4\,4\,6\right]\\ \left(\right)\end{array}\right]$

my_verification := proc(v1, v2, ver, $)
   if not (v1 :: Vector and v2 :: Vector) then
     return false;
   elif numelems(v1) <> numelems(v2) then
     return false;
   end if;
   for local i to numelems(v1) do
     if not verify([v1[i]], [v2[i]], Bracket({(truefalse &, ver), %NULL})) then
       return false;
     end if;
   end do;
   return true;
 end proc;

$\mathrm{my\_verification}≔\mathbf{proc}\left(\mathrm{v1}\&comma;\mathrm{v2}\&comma;\mathrm{ver}\&comma;\$\right)\mathbf{local}i\&semi;\mathbf{if}\mathbf{not}\left(\mathrm{v1}::\mathrm{Vector}\mathbf{and}\mathrm{v2}::\mathrm{Vector}\right)\mathbf{then}\mathbf{return}\mathrm{false}\mathbf{elif}\mathrm{numelems}\left(\mathrm{v1}\right)<>\mathrm{numelems}\left(\mathrm{v2}\right)\mathbf{then}\mathbf{return}\mathrm{false}\mathbf{end\; if}\&semi;\mathbf{for}i\mathbf{to}\mathrm{numelems}\left(\mathrm{v1}\right)\mathbf{do}\mathbf{if}\mathbf{not}\mathrm{verify}\left(\left[\mathrm{v1}\&lsqb;i\&rsqb;\right]\&comma;\left[\mathrm{v2}\&lsqb;i\&rsqb;\right]\&comma;\mathrm{VerifyTools}:-\mathrm{Bracket}\left(\left\{\mathrm{\%NULL}\&comma;\mathrm{truefalse}\&,\mathrm{ver}\right\}\right)\right)\mathbf{then}\mathbf{return}\mathrm{false}\mathbf{end\; if}\mathbf{end\; do}\&semi;\mathbf{return}\mathrm{true}\mathbf{end\; proc}$

$\mathrm{AddVerification}\left(\mathrm{my\_Vector}\&comma;\mathrm{my\_verification}\right)$

$\mathrm{verify}\left(v\&comma;w\&comma;\mathrm{my\_Vector}\left(\mathrm{as\_set}\right)\right)$

$\mathrm{true}$

$\mathrm{verify}\left(v\&comma;w\&comma;\mathrm{my\_Vector}\left(\mathrm{as\_list}\right)\right)$

$\mathrm{false}$