Let's say I have a string, maybe "Enable && Signal" for simplicity's sake.

I'd like to convert this string to standard && operations in tcl, such that Enable && Signal would return 0 if any of the value is false and 1 only when both are true.

Is there an easy way to do this, As for my case i would need a generic method where the number of arguments can be any and perform logical/relational operations like && || == <= > != etc

Any help and insights would be very much appreciated.

Thanks

I initially tried to split the arguments into conditions list and data list but could not handled the precedence of operations. Like == need to be done first and later && operations for n^n combinations

CodePudding user response：

I'm assuming that in your example, Enable and Signal are Tcl variables. So, all that would be needed to be able to pass the string to expr is to prepend a '$' to all identifiers. That can be done with regsub as follows:

set str "Enable && Signal"
regsub -all {\m[A-Za-z]\w*\M} $str {$&} expr
set result [expr $expr]

Due to the \m\M, This will properly leave numbers like 1e3 alone. But this method falls short if you also want to be able to use functions, like sin(x). If that is also a requirement, a negative lookahead may help:

set str "sin(x) * cos(y)"
regsub -all {\m[A-Za-z]\w*\M(?!\()} $str {$&} expr
puts $expr

This produces: sin($x) * cos($y)