a # 1 63 R ' mat#headings output matrix;s;i;a;`a;v;w;h;Lio                 '
a # a,[1]  '"output - center headings over formatted columns.              '
a # a,[1]  '"from ''the apl handbook of techniques'' copyright 1978, ibm.    '
a # a,[1]  '"-headings, a character vector with blank delimiters, will be  '
a # a,[1]  '" centered over the appropriate columns, and unerscored to     '
a # a,[1]  '" the full width of those columns in the preformatted matrix.  '
a # a,[1]  '"-any heading too wide for its columns will be noted.          '
a # a,[1]  '"-any insufficient number of headings will cause length error. '
a # a,[1]  '"-only the leftmost headings will be used.                     '
a # a,[1]  '"-uses: hdma hnext`a hcntr hwidth hdlb                         '
a # a,[1]  '"-generates a global variable, `b, which can be used to reduce '
a # a,[1]  '" (then expand) the result by eliminating blank columns.       '
a # a,[1]  ' mat#(1URmatrix)R'' '',s#(i#~Lio#1)R`a#headings                  '
a # a,[1]  ' w#''`b''width matrix                                            '
a # a,[1]  'back:$((i=Rw)V0=Rh#next`a)/final                               '
a # a,[1]  ' $(0^=Ra H s#s,a#w[i#i+1]cntr h)/back                          '
a # a,[1]  ' $0,RL#''column width ('',(Fw),'') too narrow for '',h             '
a # a,[1]  'final:mat[`b/IR`b]#s                                           '
a # a,[1]  ' mat#(mat,[0.1]`b\''-''),[1]matrix                               '
Lfx a