Strange compiler errors

[Parker]

I'm trying to write a class function that skips whitespace (tabs, comments, spaces, the BASIC _\n continuation character) but I'm getting very odd compiler errors.

Code Select Expand

Lexer::SkipWhitespace()
{
// We can skip any number of -
// - Comments
// - Spaces and tabs
// - 0x0A
// - _\n
byte ch;

wsagain:
switch (*(Lexer)this.lookahead(0))
{
case /*_*/ 95: // We have to allow the 3 types of newlines.
if ((*(Lexer)this.lookahead(1) = 0x0A and *(Lexer)this.lookahead(2) = 0x0D))
{
*(Lexer)this.input();
*(Lexer)this.input();
*(Lexer)this.input();
m_uLine++;
}
else if ((*(Lexer)this.lookahead(1) = 0x0D) or (*(Lexer)this.lookahead(1) = 0x0A))
{
*(Lexer)this.input();
*(Lexer)this.input();
m_uLine++;
}
else
{
return;
}
case /*space*/ 32:
case& /*tab*/ 9:
case& 0x0A:
*(Lexer)this.input();
case /*'*/ 39:
// Go until a 0x0A or 0x0D character.
_cagain:
ch = *(Lexer)this.input();
if (ch = 0x0A or ch = 0x0D or ch = 0) unput();
goto _cagain;
default:
return;
}

goto wsagain;
return;
}

And the output

Compiling...
Zen.src
Lexer.src
File: C:\dev\ac\Zen\Lexer.src (130) Warning: RETURN value expected.
File: C:\dev\ac\Zen\Lexer.src (163) unknown method -

File: C:\dev\ac\Zen\Lexer.src (164) unknown method -

File: C:\dev\ac\Zen\Lexer.src (165) unknown method -

File: C:\dev\ac\Zen\Lexer.src (167) unknown method -

Error(s) in compiling C:\dev\ac\Zen\Lexer.src

If I hadn't added the *(Lexer)this. part to each input and lookahead function, it gives me "Undefined function - this" errors, so does the assembler. I looked at the output, and it's trying to call $this.

[Bruce Peaslee]

I'm not sure I would be of any help with this, but I can't match up error line numbers with a code fragment.

[Ionic Wind Support Team]

I would check your class definitions carefully, and any include files your using.

[Parker]

I have looked at my class definition, the function, and the assembly output quite a few times and still can't figure out what's wrong.

This is the class definition, and no includes are being used.

Code Select Expand

class Lexer
{
unsigned int m_uPos;
unsigned int m_uLen;
unsigned int m_uLine;
string *m_pText;
// Values used by a token getting method
string *m_pVal; // I want this to be a union but they aren't implemented yet :(

declare Lexer();
declare _Lexer();

declare OpenFile(string filename);
declare OpenString(string str);

declare input(),byte; // Reads a char
declare lookahead(int cnt),byte; // Reads a char without incrementing position
declare unput(); // Puts back a char
declare isend(),int;

declare GetToken(),int;
declare GetWord(),int;
/* declare GetString(),int;
declare GetNumber(),int;
declare GetOper(),int;
declare GetNL(),int;
declare GetHTML(),int;*/

// Skips whitespace
// Whitespace is defined as spaces, tabs, line comments and block comments
// Also the _\n character is accepted, but increments the line count.
// Finally, the 0x0A character is discarded. Newlines must contain a 0x0D.
declare SkipWhitespace();
}

Like I said above, it generates lots of call $this instructions. Or at least it used to until I added the *(Lexer)this. lines. Now it generates nothing or at least doesn't attempt an assemble. The lines that give compiler errors are the ones that say "case /*space*/ 32:", "case& /*tab*/ 9:", "case& 0x0A:", and "case /*'*/ 39:".

I'm really sorry if it's just a dumb error on my part, but I can't see anything at all.

[Ionic Wind Support Team]

Change your switch statement to:

tmp = lookahead(0);
switch(tmp)
{
...
}

Something about using a class method in the switch statment was messing it up.  Also the lookahead(0) would have been executed for each 'case' statement, probably not what you would want anyway.

[Ionic Wind Support Team]

And the underlying bug has been fixed now.  Still you should use the temporary variable since each case comparison will execute the switch clause.

[Parker]

Thanks, it's good to know I wasn't missing something obvious. It compiles fine now.