# -*- shell-script -*-
# display.sh - gdb-like "display" debugger command
#
#   Copyright (C) 2002-2003, 200-2011, 2016
#   Rocky Bernstein <rocky@gnu.org>
#
#   This program is free software; you can redistribute it and/or
#   modify it under the terms of the GNU General Public License as
#   published by the Free Software Foundation; either version 2, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#   General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this Program; see the file COPYING.  If not, write to
#   the Free Software Foundation, 59 Temple Place, Suite 330, Boston,
#   MA 02111 USA.

_Dbg_help_add display \
"**display** [*stmt*]

Evalute *stmt* each time the debugger is stopped. If *stmt* is omitted, evaluate
all of the display statements that are active. In contrast, **info display**
shows the display statements without evaluating them.

Examples:
---------

  display echo \$x  # show the current value of x each time debugger stops
  display          # evaluate all display statements

See also:
---------

**undisplay** and **info display**."

# Set display command or list all current display expressions
proc _Dbg_do_display {
  if (( 0 == $# )) {
    _Dbg_eval_all_display
  } else {
    typeset -i n=_Dbg_disp_max++
    _Dbg_disp_exp[$n]="$ifsjoin(Argv)"
    _Dbg_disp_enable[$n]=1
    _Dbg_printf '%2d: %s' $n $(_Dbg_disp_exp[$n])
  }
  return 0
}
(CommandList
  children: [
    (C {(_Dbg_help_add)} {(display)} 
      {
        (DQ ("**display** [*stmt*]\n") ("\n") 
          ("Evalute *stmt* each time the debugger is stopped. If *stmt* is omitted, evaluate\n") ("all of the display statements that are active. In contrast, **info display**\n") 
          ("shows the display statements without evaluating them.\n") ("\n") ("Examples:\n") ("---------\n") ("\n") ("  display echo ") 
          (EscapedLiteralPart token:<Lit_EscapedChar "\\$">) ("x  # show the current value of x each time debugger stops\n") 
          ("  display          # evaluate all display statements\n") ("\n") ("See also:\n") ("---------\n") ("\n") ("**undisplay** and **info display**.")
        )
      }
    )
    (FuncDef
      name: _Dbg_do_display
      body: 
        (BraceGroup
          children: [
            (If
              arms: [
                (if_arm
                  cond: [
                    (Sentence
                      child: 
                        (DParen
                          child: 
                            (ArithBinary
                              op_id: Arith_DEqual
                              left: (ArithWord w:{(Lit_Digits 0)})
                              right: (ArithWord w:{($ VSub_Pound "$#")})
                            )
                        )
                      terminator: <Op_Semi ";">
                    )
                  ]
                  action: [(C {(_Dbg_eval_all_display)})]
                  spids: [-1 112]
                )
              ]
              else_action: [
                (C {(typeset)} {(-i)} 
                  {(Lit_VarLike "n=") (_Dbg_disp_max) (Lit_Other "+") (Lit_Other "+")}
                )
                (C 
                  {(_Dbg_disp_exp) (Lit_Other "[") ($ VSub_Name "$n") (Lit_Other "]") (Lit_Other "=") 
                    (DQ ($ VSub_At "$@"))
                  }
                )
                (C 
                  {(_Dbg_disp_enable) (Lit_Other "[") ($ VSub_Name "$n") (Lit_Other "]") 
                    (Lit_Other "=") (1)
                  }
                )
                (C {(_Dbg_printf)} {(SQ <"%2d: %s">)} {($ VSub_Name "$n")} 
                  {
                    (DQ 
                      (BracedVarSub
                        token: <VSub_Name _Dbg_disp_exp>
                        bracket_op: (ArrayIndex expr:(ArithWord w:{($ VSub_Name "$n")}))
                        spids: [158 163]
                      )
                    )
                  }
                )
              ]
              spids: [118 167]
            )
            (ControlFlow token:<ControlFlow_Return return> arg_word:{(0)})
          ]
          spids: [95]
        )
      spids: [91 94]
    )
  ]
)