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Treat invalid escape sequences as errors. 

This applies to octal and hexadecimal sequences with out-of-range values, and also to unrecognized escape characters. The C standards say both of these cases are syntax/constraint violations requiring a diagnostic.
This commit is contained in:
Stephen Heumann 2021-08-31 18:36:06 -05:00
parent 00cc05a6a1
commit b8c332deeb
2 changed files with 30 additions and 7 deletions
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33
Scanner.pas
View File

@ -715,6 +715,7 @@ if list or (numErr <> 0) then begin
159: msg := @'_Generic expression includes multiple default cases';
160: msg := @'no matching association in _Generic expression';
161: msg := @'illegal operator in a constant expression';
162: msg := @'invalid escape sequence';
otherwise: Error(57);
end; {case}
writeln(msg^);
@ -3751,13 +3752,14 @@ var
cnt: 0..3; {for counting octal escape sequences}
dig: 0..15; {value of a hex digit}
skipChar: boolean; {get next char when done?}
val: 0..4095; {hex escape code value (scaled to 0..255)}
val: 0..maxint; {hex/octal escape code value}
begin {EscapeCh}
1: skipChar := true;
if lch = '\' then begin
NextCh;
if lch in ['0'..'7','a','b','t','n','v','f','p','r','x'] then
if lch in ['0'..'7','a','b','t','n','v','f','p','r','x',
'''','"','?','\'] then
case lch of
'0','1','2','3','4','5','6','7': begin
val := 0;
@ -3767,6 +3769,8 @@ var
cnt := cnt+1;
NextCh;
end; {while}
if (val & $FF00) <> 0 then
Error(162);
EscapeCh := val & $FF;
skipChar := false;
end;
@ -3792,15 +3796,22 @@ var
dig := ord(lch)-ord('A')+10;
end; {else}
val := (val << 4) | dig;
if (val & $FF00) <> 0 then begin
Error(162);
val := 0;
end; {if}
NextCh;
end; {while}
skipChar := false;
EscapeCh := val & $FF;
end;
'''','"','?','\': EscapeCh := ord(ch);
otherwise: Error(57);
end {case}
else
else begin
Error(162);
EscapeCh := ord(lch);
end; {else}
end {if}
else
EscapeCh := ord(lch);
@ -4222,7 +4233,7 @@ var
cnt: 0..3; {for counting octal escape sequences}
dig: 0..15; {value of a hex digit}
skipChar: boolean; {get next char when done?}
val: 0..4095; {hex escape code value (scaled to 0..255)}
val: 0..maxint; {hex/octal escape code value}
codePoint: ucsCodePoint; {code point given by UCN}
chFromUCN: integer; {character given by UCN (converted)}
@ -4230,7 +4241,8 @@ var
1: skipChar := true;
if ch = '\' then begin
NextCh;
if ch in ['0'..'7','a','b','t','n','v','f','p','r','x','u','U'] then
if ch in ['0'..'7','a','b','t','n','v','f','p','r','x','u','U',
'''','"','?','\'] then
case ch of
'0','1','2','3','4','5','6','7': begin
val := 0;
@ -4240,6 +4252,8 @@ var
cnt := cnt+1;
NextCh;
end; {while}
if (val & $FF00) <> 0 then
Error(162);
EscapeCh := val & $FF;
skipChar := false;
end;
@ -4265,6 +4279,10 @@ var
dig := ord(ch)-ord('A')+10;
end; {else}
val := (val << 4) | dig;
if (val & $FF00) <> 0 then begin
Error(162);
val := 0;
end; {if}
NextCh;
end; {while}
skipChar := false;
@ -4281,10 +4299,13 @@ var
Error(146);
end; {else}
end;
'''','"','?','\': EscapeCh := ord(ch);
otherwise: Error(57);
end {case}
else
else begin
Error(162);
EscapeCh := ord(ch);
end; {else}
end {if}
else
EscapeCh := ord(ch);

4
cc.notes
View File

@ -123,7 +123,9 @@ String and character constants may now contain universal character names, a type
p. 240
The discussion of escape sequences states that hexadecimal numeric escape sequences can contain from one to three digits. This was true until ORCA/C 2.1, when the compiler was changed to respect the ANSI C standard. The compiler will now scan a hexadecimal numeric escape sequence until no more hexadecimal characters are found. The result is then anded with 0x00FF to yield a single character. (ORCA/C 2.1 would also scan an octal escape sequence until no more octal characters were found, but this has been changed back to limit octal escape sequences to at most three octal digits, as required by the C standards.)
The discussion of escape sequences states that hexadecimal numeric escape sequences can contain from one to three digits. This was true until ORCA/C 2.1, when the compiler was changed to respect the ANSI C standard. The compiler will now scan a hexadecimal escape sequence until no more hexadecimal characters are found. (ORCA/C 2.1 would also scan an octal escape sequence until no more octal characters were found, but this has been changed back to limit octal escape sequences to at most three octal digits, as required by the C standards.)
The value of an octal or hexadecimal escape sequence must be within the range of representable character values (0-255). Also, \ may not be followed by a character other than one of the ones described as forming an escape sequence. ORCA/C now gives an error in these cases. Accordingly, the examples of "\410" and '\g' mentioned in the manual are now treated as errors.
p. 241