PACKET command handler DEFINES                (* Autor: J.Liedtke *)
                                              (* Stand:  29.02.82 *)
       command handler ,
       do command ,
       command error ,
       set command :
 
 
LET esc          = ""27"" ,
    esc k        = ""27"k" ,
    cr lf        = ""4""13""10"" ,
    command pre  = ""4""13"      " ,
    command post =    ""13""10"      " ,
 
    tag type = 1 ,
    texttype = 4 ,
    eof type = 7 ;
 
 
TEXT VAR command line := "" ,
         previous command line := "" ,
         symbol ,
         procedure ,
         pattern ,
         error note := "" ;
 
INT VAR  symbol type ,
         allowed type := 0 ;
 
 
PROC set command (TEXT CONST command, INT CONST type) :

  param position (0) ;
  command line := command ;
  allowed type := type
 
ENDPROC set command ;
 
PROC do command :
 
  do (command line)

ENDPROC do command ;

 
PROC command handler ( TEXT CONST command list,
                       INT VAR command index, number of params,
                       TEXT VAR param 1, param 2,
                       TEXT CONST command text ) :
 
prepare and get command ;
command handler (command list,command index,number of params,param1,param2).
 
prepare and get command :
  set line nr (0) ;
  error protocoll ;
  get command from console .
 
error protocoll :
  IF is error
    THEN put error ;
         clear error
    ELSE command line := "" ;
  FI .
 
get command from console :
  INT VAR x, y;
  out (crlf) ;
  get cursor (x, y) ;
  cursor (x, y) ;
  REP
    out (command pre) ;
    out (command text) ;
    out (command post) ;
    editget command
  UNTIL command line <> "" PER ;
  param position (LENGTH command line) ;
  out (command post) .
 
editget command :
  feldaudit ("") ;
  feldlernmodus (FALSE) ;
  REP
    feldtabulator ("") ;
    feldseparator (esc) ;
    editget (command line) ;
    ignore halt errors during editget ;
    IF feldzeichen = esc k
      THEN command line := previous command line
      ELSE previous command line := command line ;
           LEAVE editget command
    FI
  PER .

ignore halt errors during editget :
  IF is error
    THEN clear error
  FI .

ENDPROC command handler ;
 
PROC command handler ( TEXT CONST command list,
                       INT VAR command index, number of params,
                       TEXT VAR param 1, param 2) :
 
  scan (command line) ;
  next symbol ;
  IF pos (command list, symbol) > 0
    THEN procedure name ;
         parameter list pack option ;
         nothing else in command line ;
         decode command
    ELSE impossible command
  FI .
 
procedure name :
  IF symbol type = tag type OR symbol = "?"
    THEN procedure := symbol ;
         next symbol
    ELSE error ("incorrect procedure name")
  FI .
 
parameter list pack option :
  number of params := 0 ;
  param 1 := "" ;
  param 2 := "" ;
  IF symbol = "("
    THEN next symbol ;
         parameter list ;
         IF symbol <> ")"
           THEN error (") expected")
         FI
  ELIF symbol type <> eof type
    THEN error ("( expected")
  FI .
 
parameter list :
  parameter (param 1, number of params) ;
  IF symbol = ","
    THEN next symbol ;
         parameter (param 2, number of params) ;
  FI ;
  IF symbol <> ")"
    THEN error (") expected")
  FI .
 
nothing else in command line :
  next symbol ;
  IF symbol <> ""
    THEN error ("command too complex")
  FI .

decode command :
  command index := index (command list, procedure, number of params) .
 
impossible command :
  command index := 0 .
 
ENDPROC command handler ;
 
PROC parameter (TEXT VAR param, INT VAR number of params) :
 
  IF symbol type = text type OR symbol type = allowed type
    THEN param := symbol ;
         number of params INCR 1 ;
         next symbol
    ELSE error ("parameter is no text denoter ("" missing!)")
  FI
 
ENDPROC parameter ;
 
INT PROC index (TEXT CONST list, procedure, INT CONST params) :
 
  pattern := procedure ;
  pattern CAT ":" ;
  INT CONST index pos := pos (list, pattern) ;
  IF procedure name found
    THEN get colon pos ;
         get dot pos ;
         get end pos ;
         get command index ;
         get param index ;
         IF param index >= 0
           THEN command index + param index
           ELSE - command index
         FI
    ELSE 0
  FI .
 
procedure name found :
  index pos > 0  AND  (list SUB index pos - 1) <= "9"  .
 
get param index :
  INT CONST param index :=
            pos (list, text (params), dot pos, end pos) - dot pos - 1 .
 
get command index :
  INT CONST command index :=
            int ( subtext (list, colon pos + 1, dot pos - 1) ) .
 
get colon pos :
  INT CONST colon pos := pos (list, ":", index pos) .
 
get dot pos :
  INT CONST dot pos := pos (list, ".", index pos) .
 
get end pos :
  INT CONST end pos := dot pos + 4 .
 
ENDPROC index ;
 
PROC error (TEXT CONST message) :
 
  error note := message ;
  scan ("") ;
  procedure := "-"
 
ENDPROC error ;
 
PROC command error :

  disable stop ;
  IF error note <> ""
    THEN errorstop (error note) ;
         error note := ""
  FI ;
  enable stop

ENDPROC command error ;


PROC next symbol :
 
  next symbol (symbol, symbol type)
 
ENDPROC next symbol ;
 
iNDPACKET command handler ;