Разработка программы-компилятора

begin

Termyes: =0; // флаг: найдена ли лексема

if (NumTerm<>0) and (str_lex<>'') then

begin

if (CompareStr (Term_tab [Curr_term]. lex,str_lex) >0) and (Term_tab [Curr_term]. Left<>0) then

Search_Term (Term_tab [Curr_term]. Left,str_lex); // рекурсивный "спуск по дереву"

if (CompareStr (Term_tab [Curr_term]. lex,str_lex) <0) and (Term_tab

[Curr_term]. Right<>0) then

Search_Term (Term_tab [Curr_term]. Right,str_lex);

if Term_tab [Curr_term]. lex=str_lex then Termyes: =Term_tab [Curr_term]. nomer;

end;

end;

// функция распознавания 16-рич. констант

function FConst (str: string): integer;

var

sost: byte;

begin

sost: =0;

if str [1] ='$' then // распознаём символ '$'

begin

sost: =1;

delete (str,1,1);

end

else exit;

if (str [1] ='+') or (str [1] ='-') then // распознаём знак

begin

sost: =2;

delete (str,1,1)

end

else begin sost: =4; exit; end;

if str='' then exit;

while length (str) >0 do begin

if (str [1] in cifra) or (str [1] in bukva)

then sost: =2 // распознаём буквы или цифры

else begin sost: =4; exit;

end;

delete (str,1,1);

end;

sost: =3;

if sost=3 then FConst: =1 else FConst: =-1;

end;

function termin: integer; // распознаватель терминальных символов

begin

termin: =-1;

for k: =1 to 14 do if Words [k] =Lexem then termin: =3;

for k: =1 to 8 do if Razdel [k] =Lexem then termin: =1;

for k: =1 to 11 do if Operacii [k] =Lexem then termin: =2;

end;

function Rome (str: string): integer; // распознаватель римских констант

var sost: byte;

begin

sost: =0;

if (str [1] ='-') or (str [1] ='+')

then begin sost: =12; delete (str,1,1); end;

if str='' then exit;

if str [1] ='X'

then begin sost: =1; delete (str,1,1) end

else begin

if str [1] ='V' then begin sost: =2; delete (str,1,1) end

else begin

if str [1] ='I' then begin sost: =3; delete (str,1,1) end

else begin sost: =4; exit; end; end; end;

while Length (str) <>0 do begin

case sost of

1: if str [1] ='X'

then begin sost: =5; delete (str,1,1) end

else begin

if str [1] ='V' then begin sost: =2; delete (str,1,1) end

else begin

if str [1] ='I' then begin sost: =3; delete (str,1,1) end

else begin sost: =4; exit; end; end; end;

2: if str [1] ='I'

then begin sost: =7; delete (str,1,1) end

else begin sost: =4; exit; end;

3: if str [1] ='X'

then begin sost: =8; delete (str,1,1) end

else begin

if str [1] ='V' then begin sost: =9; delete (str,1,1) end

else begin

if str [1] ='I' then begin sost: =10; delete (str,1,1) end

else begin sost: =4; exit; end; end; end;

4: exit;

5: if str [1] ='X'

then begin sost: =6; delete (str,1,1) end

else begin

if str [1] ='V' then begin sost: =2; delete (str,1,1) end

else begin

if str [1] ='I' then begin sost: =3; delete (str,1,1) end

else begin sost: =4; exit; end; end; end;

6: if str [1] ='V'

then begin sost: =2; delete (str,1,1) end

else begin

if str [1] ='I' then begin sost: =3; delete (str,1,1) end

else begin sost: =4; exit; end; end;

7: if str [1] ='I'

then begin sost: =10; delete (str,1,1) end

else begin sost: =4; exit; end;

8: begin sost: =4; exit; end;

9: begin sost: =4; exit; end;

10: if str [1] ='I'

then begin sost: =11; delete (str,1,1) end

else begin sost: =4; exit; end;

11: begin sost: =4; exit; end;

end;

end;

if (sost=4) or (sost=12) then Rome: =-1 else Rome: =1;

end;

// функция распознавания идентификаторов

function Ident (str: string): integer;

var

sost: byte;

begin

sost: =0; // реализация конечного автомата

if str [1] in ['a'. 'z'] then

begin

sost: =1;

delete (str,1,1)

end

else exit;

while length (str) >0 do begin

if str [1] in ['a'. 'z','0'. '9','_']

then begin sost: =1; delete (str,1,1); end

else begin sost: =3; exit; end;

end;

sost: =2;

if sost=2 then ident: =1 else ident: =-1;

end;

procedure WriteCode (nomer: integer; lex: string; typ: char; num: integer); // запись в таблицу кодов лексем

begin

Code_Tab [NumLex]. nomer: =nomer;

Code_Tab [NumLex]. Lex: =lex;

Code_Tab [NumLex]. typ: =typ;

Code_Tab [NumLex]. Num: =num;

Code_Tab [NumLex]. numstr: =string_counter+1;

end;

procedure WriteLex (typelex: char); // запись лексем в таблицы

begin

case typelex of

'C': begin // если лексема-16-рич. константа

NumLex: =NumLex+1;

Search_Const (1,Lexem);

if Constyes=0 then // если лексема не найдена

begin

NumConst: =NumConst+1;

Add_Const (1,Lexem);

Const_tab [NumConst]. Typ: ='16-рич. ';

Const_tab [Numconst]. Width: ='2 байта';

WriteCode (NumLex,Lexem,'C',NumConst);

end else // если лексема найдена

begin

WriteCode (NumLex,Lexem,'C',Constyes);

end;

end;

'M': begin // если лексема-римская константа

NumLex: =NumLex+1;

Search_Const (1,Lexem);

if Constyes=0 then // если лексема не найдена

begin

NumConst: =NumConst+1;

Add_Const (1,Lexem);

Const_tab [NumConst]. Typ: ='римск. ';

Const_tab [Numconst]. Width: ='2 байта';

WriteCode (NumLex,Lexem,'C',NumConst);

end else // если лексема найдена

begin

WriteCode (NumLex,Lexem,'C',Constyes);

end;

end;

'I': begin // если лексема-идентификатор

NumLex: =NumLex+1;

y: =Search_Ident ({1,}Lexem);

if y=0 then // если лексема не найдена

begin

NumId: =NumId+1;

WriteCode (NumLex,Lexem,'I',NumId);

Add_Ident (Lexem);

end else WriteCode (NumLex,Lexem,'I',y); // если лексема найдена

end;

'K': begin // если лексема-служебное слово

NumLex: =NumLex+1;

Search_Term (1,Lexem);

if Termyes=0 then // если лексема не найдена

begin

NumTerm: =NumTerm+1;

Add_Term (1,Lexem);

Term_tab [Numterm]. razd: =0;

Term_tab [Numterm]. oper: =0;

Term_tab [Numterm]. slug: =1;

WriteCode (NumLex,Lexem,'T',NumTerm);

end else WriteCode (NumLex,Lexem,'T',Termyes); // если лексема найдена

end;

'R': begin // если лексема-разделитель

NumLex: =NumLex+1;

Search_Term (1,Lexem);

if Termyes=0 then // если лексема не найдена

begin

NumTerm: =NumTerm+1;

Add_Term (1,Lexem);

Term_tab [NumTerm]. razd: =1;

Term_tab [NumTerm]. oper: =0;

Term_tab [NumTerm]. slug: =0;

WriteCode (NumLex,Lexem,'T',NumTerm)

end else WriteCode (NumLex,Lexem,'T',Termyes) // если лексема найдена

end;

'O': begin // если лексема-знак операция

NumLex: =NumLex+1;

Search_Term (1,Lexem);

if Termyes=0 then // если лексема не найдена

begin

NumTerm: =NumTerm+1;

Add_Term (1,Lexem);

Term_tab [Numterm]. razd: =0;

Term_tab [Numterm]. oper: =1;

Term_tab [Numterm]. slug: =0;

WriteCode (NumLex,Lexem,'T',NumTerm)

 Скачать реферат