`-=

No, since the terminal `+= exists in the grammar and the lexer is constructed to always choose the longest possible terminal. So if `-= was added to the grammar then it would be just as wrong to parse the sequence `-= as two tokens.

(This shows that it isn't so easy to extend the set of operator tokens and backquote identifiers. If the new token is a concatenation of shorter tokens then one must make sure that the concatenation isn't grammatically valid anywhere in the language.)

/ Martin Stjernholm, Roxen IS

Previous text:

2003-04-05 19:23: Subject: `-=

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That is of course a problem. Does that mean that it is an error in the grammar that

int `+ =7;

works but

int `+=7;

does not?

/ Martin Nilsson (har bott i google)