{$A-}
PROGRAM CHAPTER5;
{$I TOOLU.PAS}
{$I FPRIMS.PAS}


PROCEDURE FIND;

VAR
  ARG,LIN,PAT:XSTRING;

FUNCTION GETPAT(VAR ARG,PAT:XSTRING):BOOLEAN;
BEGIN
  GETPAT:=(MAKEPAT(ARG,1,ENDSTR,PAT)>0)
END;


BEGIN
  IF(NOT GETARG(2,ARG,MAXSTR))THEN
    ERROR('Usage: find pattern');
  IF (NOT GETPAT(ARG,PAT)) THEN
    ERROR('FIND: illegal pattern');
  WHILE(GETLINE(LIN,STDIN,MAXSTR))DO
    IF (MATCH(LIN,PAT))THEN
      PUTSTR(LIN,STDOUT)
END;
 
PROCEDURE CHANGE;
CONST
  DITTO=255;
VAR
  LIN,PAT,SUB,ARG:XSTRING;

FUNCTION GETPAT(VAR ARG,PAT:XSTRING):BOOLEAN;
BEGIN
  GETPAT:=(MAKEPAT(ARG,1,ENDSTR,PAT)>0)
END;

FUNCTION GETSUB(VAR ARG,SUB:XSTRING):BOOLEAN;

FUNCTION MAKESUB(VAR ARG:XSTRING; FROM:INTEGER;
  DELIM:CHARACTER; VAR SUB:XSTRING):INTEGER;
VAR I,J:INTEGER;
   JUNK:BOOLEAN;
BEGIN
  J:=1;
  I:=FROM;
  WHILE (ARG[I]<>DELIM) AND (ARG[I]<>ENDSTR) DO BEGIN
    IF(ARG[I]=ORD('&')) THEN
      JUNK:=ADDSTR(DITTO,SUB,J,MAXPAT)
    ELSE
      JUNK:=ADDSTR(ESC(ARG,I),SUB,J,MAXPAT);
    I:=I+1
  END;
  IF (ARG[I]<>DELIM) THEN
    MAKESUB:=0
  ELSE IF (NOT ADDSTR(ENDSTR,SUB,J,MAXPAT)) THEN
    MAKESUB:=0
  ELSE
    MAKESUB:=I
END;

BEGIN
  GETSUB:=(MAKESUB(ARG,1,ENDSTR,SUB)>0)
END;

PROCEDURE SUBLINE(VAR LIN,PAT,SUB:XSTRING);
VAR
  I, LASTM, M:INTEGER;
  JUNK:BOOLEAN;


PROCEDURE PUTSUB(VAR LIN:XSTRING; S1,S2:INTEGER;
  VAR SUB:XSTRING);
VAR
  I,J:INTEGER;
  JUNK:BOOLEAN;
BEGIN
  I:=1;
  WHILE (SUB[I]<>ENDSTR) DO BEGIN
    IF(SUB[I]=DITTO) THEN
      FOR J:=S1 TO S2-1 DO
        PUTC(LIN[J])
      ELSE
        PUTC(SUB[I]);
      I:=I+1
  END
END;

BEGIN
  LASTM:=0;
  I:=1;
  WHILE(LIN[I]<>ENDSTR) DO BEGIN
    M:=AMATCH(LIN,I,PAT,1);
    IF (M>0) AND (LASTM<>M) THEN BEGIN
      PUTSUB(LIN,I,M,SUB);
      LASTM:=M
    END;
    IF (M=0) OR (M=I) THEN BEGIN
      PUTC(LIN[I]);
      I:=I+1
    END
    ELSE
      I:=M
    END
END;

BEGIN
  IF(NOT GETARG(2,ARG,MAXSTR)) THEN
    ERROR('Usage: change from [to]');
  IF (NOT GETPAT(ARG,PAT)) THEN
    ERROR('CHANGE: illegal "from" pattern');
  IF (NOT GETARG(3,ARG,MAXSTR)) THEN
    ARG[1]:=ENDSTR;
  IF(NOT GETSUB(ARG,SUB)) THEN
    ERROR('CHANGE: illegal "to" string');
  WHILE (GETLINE(LIN,STDIN,MAXSTR)) DO
    SUBLINE(LIN,PAT,SUB)
END;

PROCEDURE COMMAND;
BEGIN
       IF (GlobalArg1='change')THEN CHANGE
  ELSE IF (GlobalArg1='find')THEN FIND
  ELSE ERROR('Chap 5: can''t happen');
END;

BEGIN
  COMMAND;
  ENDCMD;
END.