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Topic: Overriding the single quote (')
Replies: 2   Last Post: May 23, 2013 3:50 AM

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 LBoogie Posts: 10 Registered: 3/15/07
Overriding the single quote (')
Posted: May 17, 2013 4:34 AM

The Verilog "programming" language provide a compact way to describe and work with digital circuits. The language features a nifty syntax for representing bits. For example 3'b101 is the 3 bit unsigned binary number 101. 3'd5 is the same binary number but represented as the decimal 5.

I wanted to set up an expression in Mathematica such as f[3'b101] rather than the more verbose f["3'b101"].

I thought I could simply set f to hold all its arguments using SetAttributes[f,HoldAll]. But FullForm[f[3'b101]] results in f[Times[Derivative[1][2], b101]].

I tried to "control the evaluation" using \$PreRead and \$Pre. I observed that Mathematica replaces the single-quote with Derivative sometime between \$PreRead and \$Pre. The closest I got to the solution is that I've managed to assign \$PreRead a purefunction that will convert f[3'b101] to f["3'b101"]. (With 3'b101 as a string, Mathematica will not convert to Derivative.) But then, how do I set \$Post to convert f["3'b101"] to f[3'b101]?

Does anyone know how to set Mathematica to avoid replacing single-quote with a Derivative under special circumstances?

Thanks,
Lawrence

Date Subject Author
5/17/13 LBoogie
5/19/13 David Bailey
5/23/13 LBoogie