Dear Peter, Raph, and all, Peter writes:
I'm not sure exactly what you would like to do. Here is some information that might be useful for you.
As Raph deduced, I am looking to do dynamic checks of program properties and raise an exception if it's not found. I find this especially useful for testing.
The Compiler.evalExpression function takes a string and an environment and compiles and evaluates the string as an Oz expression. See: http://www.mozart-oz.org/documentation/compiler/node4.html#section.api.modul e For example, {Compiler.evalExpression "X+3" env('X':4) _} returns 7.
Thanks, I spent a while working with that, and even wrote up something that evaluates an expression in the OPI's top-level environment, which you can find at: http://www.cs.iastate.edu/~cs541/lib/OPIEval.oz But in the end, I decided that this was too error prone, as the top-level environment of the OPI is not always what is wanted, and because this wouldn't make sense in a stand alone program. So I have gone back to the simplest thing: %% Assert that the argument is true. proc {Assert B} if {Not B} then raise assertionFailed(debug:unit) end end end This certainly works, although in the OPI it is not ideal for pinpointing where the error comes from, and the message one gets doesn't display the source code for the expression that evaluated to the argument (B). For those interested, see http://www.cs.iastate.edu/~cs541/lib/Testing.oz for a module with procedures assert, assume, and test. All of these are equally simple-minded, however. My conclusion was that these simple versions were better than trying to use the compiler's evalExpression procedure, because: - I couldn't figure out how to get the current lexical environment to pass to evalExpression as an argument, and - Quoting expressions is more error-prone using expressions directly. Ideally assert would be a macro that could grab a quoted version of the expression for use in the exception. (Or it could be directly supported by the compiler.) Thanks for all your help with this. Gary T. Leavens Department of Computer Science, Iowa State University 229 Atanasoff Hall, Ames, Iowa 50011-1041 USA http://www.cs.iastate.edu/~leavens phone: +1-515-294-1580 _________________________________________________________________________________ mozart-users mailing list mozart-users@ps.uni-sb.de http://www.mozart-oz.org/mailman/listinfo/mozart-users
