/* OS/2 REXX implementation of the UNIX yes "filter" optionally   */
/* using any "local" Yes / No / Abort / Retry / Ignore character: */

   call trace 'O'                   /* disable any SET RXTRACE=ON */
   signal on novalue  name TRAP  ;  signal on syntax name TRAP
   signal on failure  name TRAP  ;  signal on halt   name TRAP
   call UTIL 'SysSleep'          ;  call UTIL 'SysGetMessage'

   YES = strip( arg( 1 ))           /* stripped arg = output line */

   if pos( left( YES, 1 ), '-/' ) > 0 then do      /* "-" or "/": */
      GOT = translate( substr( YES, 2, 1 ))        /* option char */
      YES = strip( substr( YES, 3 ))               /* white space */
      select
         when GOT = '-' then nop                   /* -- = IGNORE */
         when YES <> '' then exit TELL( YES )      /* if bad arg. */
         when \ datatype( GOT, 'w' ) then exit TELL( GOT )
         when 1 > GOT | GOT > 5      then exit TELL( GOT )
         otherwise YES = left( word( SysGetMessage( 0 ), GOT ), 1 )
      end                           /* last word is no character  */
   end
   else GOT = ''                    /* no option, default YES 'y' */

   if abbrev( YES, '"' ) & lastpos( '"', YES ) = length( YES )
      then YES = substr( YES, 2, length( YES ) - 2 )
   if YES = '' & GOT = '' then YES = 'y'

   signal on notready name DONE  /* NOTREADY: pipe broken => exit */
   do while lineout( /**/, YES ) = 0   ;  call SysSleep 1   ;  end
DONE: exit 0

TELL: procedure                  /* unknown option or -?, -h, -u  */
   parse source . . YES ;  L = x2c( 0D0A )
   M = L || L || 'usage:' YES '        | prog'
   M = M || L || 'or   :' YES '   text | prog'
   M = M || L || 'or   :' YES '-- text | prog'
   M = M || L || 'or   :' YES '-n      | prog'
   M = M || L || 'The 1st form sends yes-lines to a program.'
   M = M || L || 'The 2nd form allows to specify which text'
   M = M || L || 'is sent instead of "y", e.g. Y, n, NO, ...'
   M = M || L || 'The 3rd form is used either to send texts'
   M = M || L || 'starting with "-" or to send empty lines.'
   M = M || L || 'Finally -n (n = 1..5) sends word 1..5 of'
   M = M || L || 'SysGetMessage(0): Y N Abort Retry Ignore,'
   M = M || L || '= on this system:' SysGetMessage( 0 )
   if wordpos( arg( 1 ), '? h H u U' ) = 0
      then return TRAP( 'unknown option -' arg( 1 ) || M )
   say M ;  return 1             /* TRAP is ugly but save: STDERR */

/* see <URL:http://purl.net/xyzzy/rexxtrap.htm>, (c) F. Ellermann */

UTIL: procedure                  /* load necessary RexxUtil entry */
   if RxFuncQuery(  arg( 1 )) then
      if RxFuncAdd( arg( 1 ), 'RexxUtil', arg( 1 )) then
         exit TRAP( "can't add RexxUtil"  arg( 1 ))
   return 0

TRAP:                            /* select REXX exception handler */
   call trace 'O' ;  trace N           /* don't trace interactive */
   parse source TRAP                   /* source on separate line */
   TRAP = x2c( 0D ) || right( '+++', 10 ) TRAP || x2c( 0D0A )
   TRAP = TRAP || right( '+++', 10 )   /* = standard trace prefix */
   TRAP = TRAP strip( condition( 'c' ) 'trap:' condition( 'd' ))
   select
      when wordpos( condition( 'c' ), 'ERROR FAILURE' ) > 0 then do
         if condition( 'd' ) > ''      /* need an additional line */
            then TRAP = TRAP || x2c( 0D0A ) || right( '+++', 10 )
         TRAP = TRAP '(RC' rc || ')'   /* any system error codes  */
         if condition( 'c' ) = 'FAILURE' then rc = -3
      end
      when wordpos( condition( 'c' ), 'HALT SYNTAX'   ) > 0 then do
         if condition( 'c' ) = 'HALT' then rc = 4
         if condition( 'd' ) > '' & condition( 'd' ) <> rc then do
            if condition( 'd' ) <> errortext( rc ) then do
               TRAP = TRAP || x2c( 0D0A ) || right( '+++', 10 )
               TRAP = TRAP errortext( rc )
            end                        /* future condition( 'd' ) */
         end                           /* may use errortext( rc ) */
         else  TRAP = TRAP errortext( rc )
         rc = -rc                      /* rc < 0: REXX error code */
      end
      when condition( 'c' ) = 'NOVALUE'  then rc = -2 /* dubious  */
      when condition( 'c' ) = 'NOTREADY' then rc = -1 /* dubious  */
      otherwise                        /* force non-zero whole rc */
         if datatype( value( 'RC' ), 'W' ) = 0 then rc = 1
         if rc = 0                             then rc = 1
         if condition() = '' then TRAP = TRAP arg( 1 )
   end                                 /* direct: TRAP( message ) */

   TRAP = TRAP || x2c( 0D0A ) || format( sigl, 6 )
   signal on syntax name TRAP.SIGL     /* throw syntax error 3... */
   if 0 < sigl & sigl <= sourceline()  /* if no handle for source */
      then TRAP = TRAP '*-*' strip( sourceline( sigl ))
      else TRAP = TRAP '+++ (source line unavailable)'
TRAP.SIGL:                             /* ...catch syntax error 3 */
   if abbrev( right( TRAP, 2 + 6 ), x2c( 0D0A )) then do
      TRAP = TRAP '+++ (source line unreadable)'   ;  rc = -rc
   end
   select
      when 1 then do                   /* in pipes STDERR: output */
         parse version TRAP.REXX . .   /* REXX/Personal: \dev\con */
         signal on syntax name TRAP.FAIL
         if TRAP.REXX = 'REXXSAA'      /* fails if no more handle */
            then call lineout 'STDERR'  , TRAP
            else call lineout '\dev\con', TRAP
      end
      when 0 then do                   /* OS/2 PM: RxMessageBox() */
         signal on syntax name TRAP.FAIL
         call RxMessageBox ,           /* fails if not in PMREXX  */
            translate( TRAP, ' ', x2c( 0D )), , 'CANCEL', 'WARNING'
      end                              /* replace any CR by blank */
      otherwise   say TRAP ; trace ?L  /* interactive Label trace */
   end

   if condition() = 'SIGNAL' then signal TRAP.EXIT
TRAP.CALL:  return rc                  /* continue after CALL ON  */
TRAP.FAIL:  say TRAP ;  rc = 0 - rc    /* force TRAP error output */
TRAP.EXIT:  exit   rc                  /* exit for any SIGNAL ON  */