Problem when reading backslash in Prolog

Posted by Jerry on Stack Overflow See other posts from Stack Overflow or by Jerry
Published on 2010-05-15T20:36:12Z Indexed on 2010/05/15 20:44 UTC
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escape-character

I'm writing a lexer in Prolog which will be used as a part of functional language interpreter. Language spec allows expressions like for example let \x = x + 2; to occur. What I want lexer to do for such input is to "return":

[tokLet, tokLambda, tokVar(x), tokEq, tokVar(x), tokPlus, tokNumber(2), tokSColon]

and the problem is, that Prolog seems to ignore the \ character and "returns" the line written above except for tokLambda.

One approach to solve this would be to somehow add second backslash before/after every occurrence of one in the program code (because everything works fine if I change the original input to let \\x = x + 2;) but I don't really like it.

Any ideas?

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