3 IMPORT Strings
, DevCPM
, DevCPT
;
6 MaxIdLen
= LEN(DevCPT
.Name
);
10 if
= 1; then
= 2; else
= 3; elsif
= 4; end
= 5;
11 new
= 6; error
= 7; ident
= 8; plus
= 9; minus
= 10;
12 not
= 11; and
= 12; or
= 13; rpar
= 14; lpar
= 15; defined
= 16;
13 endcom
= 17; eof
= 18;
16 Context
= POINTER TO RECORD
17 next
: Context
; (* upper level block *)
18 alt
: BOOLEAN; (* else branch *)
19 val
: BOOLEAN; (* condition value, inverted if alt *)
20 ref
: INTEGER (* ELSIF count *)
23 Selector
= POINTER TO RECORD
30 ch
-: CHAR; (* current character *)
31 name
: DevCPT
.Name
; (* ident *)
34 sym
: BYTE; (* parser symbol *)
35 fold
: INTEGER; (* condition folding *)
40 PROCEDURE err (n
: SHORTINT);
44 PROCEDURE Identifier (VAR sym
: BYTE);
45 VAR i
, res
: INTEGER; n
: ARRAY MaxIdLen
OF CHAR;
48 n
[i
] := ch
; INC(i
); DevCPM
.Get(ch
)
49 UNTIL ~Strings
.IsIdent(ch
) OR (i
= MaxIdLen
);
50 IF i
= MaxIdLen
THEN err(240); DEC(i
) END ;
51 n
[i
] := 0X
; Strings
.StringToUtf8(n
, name
, res
); sym
:= ident
;
52 IF res
= 1 (*truncated*) THEN err(240) END
55 PROCEDURE Get (VAR sym
: BYTE);
57 DevCPM
.errpos
:= DevCPM
.curpos
- 1;
58 WHILE (ch
# DevCPM
.Eot
) & ((ch
<= " ") OR (ch
= 0A0X
)) DO DevCPM
.Get(ch
) END;
59 DevCPM
.startpos
:= DevCPM
.curpos
- 1;
61 | DevCPM
.Eot
: sym
:= eof
62 |
"&": sym
:= and
; DevCPM
.Get(ch
)
63 |
"(": sym
:= lpar
; DevCPM
.Get(ch
)
64 |
")": sym
:= rpar
; DevCPM
.Get(ch
)
66 sym
:= null
; DevCPM
.Get(ch
);
67 IF ch
= ">" THEN sym
:= endcom
; DevCPM
.Get(ch
) END
68 |
"+": sym
:= plus
; DevCPM
.Get(ch
)
69 |
"-": sym
:= minus
; DevCPM
.Get(ch
)
70 |
"D": Identifier(sym
); IF name
= "DEFINED" THEN sym
:= defined
END
71 |
"E": Identifier(sym
);
72 IF name
= "END" THEN sym
:= end
73 ELSIF name
= "ELSE" THEN sym
:= else
74 ELSIF name
= "ELSIF" THEN sym
:= elsif
75 ELSIF name
= "ERROR" THEN sym
:= error
77 |
"I": Identifier(sym
); IF name
= "IF" THEN sym
:= if
END
78 |
"N": Identifier(sym
); IF name
= "NEW" THEN sym
:= new
END
79 |
"O": Identifier(sym
); IF name
= "OR" THEN sym
:= or
END
80 |
"T": Identifier(sym
); IF name
= "THEN" THEN sym
:= then
END
81 |
"A".."C", "J".."M", "P".."S", "U".."Z", "a".."z", "_": Identifier(sym
)
82 |
"~": sym
:= not
; DevCPM
.Get(ch
)
84 IF Strings
.IsIdent(ch
) THEN Identifier(sym
) ELSE sym
:= null
; DevCPM
.Get(ch
) END
88 PROCEDURE New (IN name
: DevCPT
.Name
): Selector
;
92 WHILE (s
.next
# NIL) & (s
.next
.name$
# name$
) DO s
:= s
.next
END;
93 IF s
.next
= NIL THEN NEW(s
.next
); s
.next
.name
:= name$
; s
.next
.val
:= FALSE
99 PROCEDURE Old (IN name
: DevCPT
.Name
): Selector
;
103 WHILE (s
.next
# NIL) & (s
.next
.name$
# name$
) DO s
:= s
.next
END;
105 err(0); NEW(s
.next
); s
.next
.name
:= name$
; s
.next
.val
:= FALSE
110 PROCEDURE Find (IN name
: DevCPT
.Name
): Selector
;
114 WHILE (s
.next
# NIL) & (s
.next
.name$
# name$
) DO s
:= s
.next
END;
118 PROCEDURE Set
* (IN name
: DevCPT
.Name
; val
: BOOLEAN);
122 WHILE (s
.next
# NIL) & (s
.next
.name$
# name$
) DO s
:= s
.next
END;
123 IF s
.next
= NIL THEN NEW(s
.next
) END;
124 s
.next
.name
:= name$
; s
.next
.val
:= val
127 PROCEDURE ^
Expression (VAR x
: BOOLEAN; use
: BOOLEAN);
129 PROCEDURE Factor (VAR x
: BOOLEAN; use
: BOOLEAN);
133 IF use
THEN x
:= Old(name
).val
END; Get(sym
);
134 ELSIF sym
= defined
THEN
139 IF use
THEN x
:= Find(name
) # NIL END;
143 IF sym
# rpar
THEN err(23)
148 ELSIF sym
= lpar
THEN
149 Get(sym
); Expression(x
, use
);
150 IF sym
# rpar
THEN err(23)
154 Get(sym
); Factor(x
, use
); IF use
THEN x
:= ~x
END
160 PROCEDURE Term (VAR x
: BOOLEAN; use
: BOOLEAN);
165 Get(sym
); Factor(y
, use
& x
); IF use
& x
THEN x
:= x
& y
END
169 PROCEDURE Expression (VAR x
: BOOLEAN; use
: BOOLEAN);
174 Get(sym
); Term(y
, use
& ~x
); IF use
& ~x
THEN x
:= x
OR y
END
178 PROCEDURE Printable (): BOOLEAN;
182 WHILE (c
# NIL) & c
.val
DO c
:= c
.next
END;
186 PROCEDURE If (cond
: BOOLEAN);
189 NEW(c
); c
.next
:= top
; c
.alt
:= FALSE
; c
.val
:= cond
; c
.ref
:= 0; top
:= c
;
190 INC(fold
); skip
:= ~
Printable()
195 IF top
.alt
THEN err(14) (* double ELSE *)
196 ELSE top
.alt
:= TRUE
; top
.val
:= ~top
.val
; skip
:= ~
Printable()
203 i
:= 0; ref
:= top
.ref
; DEC(fold
, ref
+ 1);
204 WHILE (top
# NIL) & (i
<= ref
) DO top
:= top
.next
; INC(i
) END;
205 IF top
= NIL THEN err(51); fold
:= 0; If(TRUE
) END;
210 VAR val
: BOOLEAN; s
: Selector
; use
: BOOLEAN;
212 ch
:= " "; Get(sym
); use
:= ~skip
;
216 IF use
THEN s
:= New(name
) END; Get(sym
);
217 IF (sym
= plus
) OR (sym
= minus
) THEN
218 IF use
THEN s
.val
:= sym
= plus
END; Get(sym
)
222 ELSIF sym
= ident
THEN
223 IF use
THEN s
:= Old(name
) END; Get(sym
);
224 IF (sym
= plus
) OR (sym
= minus
) THEN
225 IF use
THEN s
.val
:= sym
= plus
END; Get(sym
)
228 ELSIF sym
= error
THEN
229 IF use
THEN err(501) END; Get(sym
)
231 Get(sym
); Expression(val
, use
); If(val
);
232 IF sym
= then
THEN Get(sym
)
235 ELSIF sym
= elsif
THEN
236 IF fold
<= 1 THEN err(14) END; (* ELSIF without IF *)
237 Else
; Get(sym
); Expression(val
, use
); If(val
); INC(top
.ref
);
238 IF sym
= then
THEN Get(sym
)
241 ELSIF sym
= else
THEN
242 IF fold
<= 1 THEN err(14) END; (* ELSE without IF *)
245 IF fold
<= 1 THEN err(14) END; (* END without IF *)
250 IF sym
# endcom
THEN err(5) ELSE DevCPM
.errpos
:= DevCPM
.curpos
- 1 END
255 IF fold
# 1 THEN err(14) END
260 ch
:= " "; sym
:= eof
; name
:= "";
261 fold
:= 0; top
:= NIL; scope
:= NIL;