Курсовая работа. / РЯП_Ксю / Other / Bosk_tjp / proga / src / LEX

(*
* Lex.pas - модуль Лексического Анализа
* ver. 0.37
* 21.05.2007 serg
*)

(* Список Fix-ов
* 1) isKeyword(): "Уничтожение" токенов _LOW и _HIGH (для OR и NOT), добавление токена "MOP"
* 2) get_token(): "Уничтожение" токена _LOW (для + и -)
*
* BigFix
* 3) missSpace(): фунциия теперь "пожирает" и комментарии тоже
*
* 4##) добавление операции WRTS и строк (_STR)
*
*)
unit Lex;
interface
uses uStack;
const
(* Fix 4## 1 edit - добавлен токен WRITES*)
keywords: array[0..29] of String[8] =
('AND', 'ARRAY', 'BEGIN', 'BOOLEAN', 'CONST', 'DIV', 'ELSE',
'END', 'FALSE', 'GOTO', 'IF', 'INTEGER', 'LABEL', 'MOD', 'NOT', 'OF',
'OR', 'PROGRAM', 'READ', 'REPEAT', 'THEN', 'TRUE', 'TYPE',
'UNTIL', 'VAR', 'WRITE', 'WRITES','WRITEM','CON', 'DIS');
type
Tokens = String[8];
var
lines: Word;

(* Fix 4## 2 add*)
const strMaxCount = 100;
var strTable:array[1..strMaxCount] of string[50];
var strCount: Integer;
(*end Fix 4## 2*)


function get_token(var f_in: Text; var value1, value2: String; var c: Char; var w: Boolean): Tokens;

implementation


function toUpperCase(str_in: Tokens): Tokens;
var
j: Byte;
begin
for j := 1 to Length(str_in) do
str_in[j] := UpCase(str_in[j]);
toUpperCase := str_in;
end;

function isLetter(c: Char): boolean;
var x: Byte;
begin
x := Ord(c);
if(x>64) and (x<91) or (x>96) and (x<123) then
isLetter := true
else
isLetter := false;
end;

function isNum(c: Char): boolean;
var x: Byte;
begin
x := Ord(c);
if (x>47) and (x<58) then
isNum := true
else
isNum := false;
end;

function isId(c: Char): boolean;
begin
if isLetter(c) or isNum(c) or (c='_') then
isId := true
else
isId := false;
end;

procedure isKeyword(lexem: String; var token: Tokens);
var
j: Byte;
t: String;
q: Boolean;
begin
token := '_ID';
q := false;
j := 0;
repeat
if (keywords[j] = toUpperCase(lexem)) then begin
q := true;
t := toUpperCase(lexem);
(* Fix 1 edit *)
(* "Уничтожение" токенов _LOW и _HIGH (для OR и NOT)*)
(* было *)
(*
if t = 'OR' then token := '_LOW'
else
if (t = 'AND')or(t = 'DIV')or(t = 'MOD') then token := '_MID'
else
if t = 'NOT' then token := '_HIGH'
*)
(* стало *)
if (t = 'AND')or(t = 'DIV')or(t = 'MOD') then token := '_MID'
else
if (t = 'CON')or(t = 'DIS') then
token := '_MOP'
(*end Fix 1*)

else
token := '_' + t;
end;
j := j + 1;
(* Fix 4## 3 edit *)
(* until q or (j = 27); *)
until q or (j = 30);
(* end Fix 4## 3 *)

end;


(* BigFix3 edit - фунциия теперь "пожирает" и комментарии тоже *)
function missSpace(var f_in: Text; var c: Char): Boolean;
var isComment : boolean;
begin
(* стало *)
if not (Ord(c) in [10, 13, 32, Ord('{')]) then
missSpace := false
else begin
isComment := (c='{');
while ((Ord(c) in [10, 13, 32, Ord('{')]) or isComment) and not Eof(f_in) do begin
if isComment then
isComment := (c<>'}')
else
isComment := (c='{');
Read(f_in,c);
if Ord(c) = 10 then Inc(lines);
end;
if Ord(c) in [10, 13, 32] then begin
missSpace := true
end
else
missSpace := false
end;
(* было *)
(*
if not (Ord(c) in [10, 13, 32]) then
missSpace := false
else begin
while (Ord(c) in [10, 13, 32]) and not Eof(f_in) do begin
Read(f_in,c);
if Ord(c) = 10 then Inc(lines);
end;
if Ord(c) in [10, 13, 32] then begin
{ Inc(lines);}
missSpace := true
end
else
missSpace := false
end;
*)
end;
(* BigFix3 end*)

function GoNextT(var f_in: Text; var c: Char): Boolean;
begin
if not Eof(f_in) then begin
Read(f_in, c);
GoNextT := missSpace(f_in, c);
end
else
GoNextT := true;
end;

function get_token(var f_in: Text; var value1, value2: String; var c: Char; var w: Boolean): Tokens;
var
q: Boolean;
token,s: Tokens;
p: tTable;
(*Fix 4## 4 add*)
var myStr: string;
(*end Fix 4## 4*)
begin
q := false;
value1 := '';
w := missSpace(f_in, c);
if isLetter(c) then begin
if not Eof(f_in) then
repeat
value1 := value1 + c;
Read(f_in,c);
until not isId(c) or Eof(f_in)
else w := true;
if isId(c) then begin
value1 := value1 + c;
w := true;
end
else begin
w := missSpace(f_in, c);
end;
isKeyword(value1,token);
if token = '_FALSE' then begin
value1 := 'false';
value2 := 'BOOLEAN'
end;
if token = '_TRUE' then begin
value1 := 'true';
value2 := 'BOOLEAN'
end;
if token = '_ID' then begin
{ value2 := 'INTEGER';}
p := isExist(value1);
{ Str(p^.col1,s);}
value2 := p^.col1
end;
get_token := token;
q := true;
end;
if not q and isNum(c) then begin
if not Eof(f_in) then
repeat
value1 := value1 + c;
Read(f_in,c);
until not isNum(c) or Eof(f_in)
else w := true;
if isNum(c) then begin
value1 := value1 + c;
w := true;
end
else
w := missSpace(f_in, c);
get_token := '_NUM';
value2 := 'INTEGER';
q := true;
end;
if not q and (c = '.') then begin
value1 := c;
get_token := value1;
if not Eof(f_in) then begin
Read(f_in,c);
if (c = '.') then begin
value1 := value1 + c;
w := GoNextT(f_in, c);
get_token := '_DDOT';
end
end
else w := true;
q := true;
end;
if not q and (c = ':') then begin
value1 := c;
get_token := value1;
if not Eof(f_in) then begin
Read(f_in,c);
if (c = '=') then begin
value1 := value1 + c;
w := GoNextT(f_in, c);
get_token := '_EQ';
end
end
else w := true;
q := true;
end;
if not q and (c = '<') then begin
value1 := c;
if not Eof(f_in) then begin
Read(f_in, c);
if c in ['=', '>'] then begin
value1 := value1 + c;
w := GoNextT(f_in, c);
end;
end
else w := true;
get_token := '_REL';
q := true;
end;
if not q and (c = '>') then begin
value1 := c;
if not Eof(f_in) then begin
Read(f_in, c);
if (c = '=') then begin
value1 := value1 + c;
w := GoNextT(f_in, c);
end;
end
else w := true;
get_token := '_REL';
q := true;
end;
if not q and (c = '=') then
begin
value1 := c;
get_token := '_REL';
w := GoNextT(f_in, c);
q := true;
end;
if not q and (c = '*') then
begin
value1 := c;
get_token := '_MID';
w := GoNextT(f_in, c);
q := true;
end;
if not q and (c in ['+', '-']) then
begin
value1 := c;
(* Fix 2 edit *)
(* "Уничтожение" токена _LOW (для + и -)*)
(* было *)
(* get_token := '_LOW';*)
(* стало *)
get_token := c;
(* end Fix 2 *)
w := GoNextT(f_in, c);
q := true;
end;
if not q and (c in [';', ',', '[', ']', '(', ')']) then
begin
value1 := c;
get_token := c;
w := GoNextT(f_in, c);
q := true;
end;


(*Fix 4## 5 add*)
if not q and (c = '''') then
begin
myStr := '';
if not Eof(f_in) then
repeat
if c<>'''' then myStr:= myStr+c;
Read(f_in,c);
until (c='''') or (Ord(c) in [10, 13]) or Eof(f_in)
else w := true; {==EOF}

w := GoNextT(f_in, c);
q := true;

inc(strCount);
strTable[strCount] := myStr;
str(strCount,myStr);
value1 := myStr;
value2 := 'STRING';
get_token := '_STR';
end;

(*end Fix 4## 5 *)

if not q then
get_token := 'nil';
end;

end.