1. SASSi Carl Morgan (Group Leader) Paul Salama Xiaotang Zhang

2. Why be SASSi? Our motivation was to design a language to let a user make quick and simple programs to deal with various statistical problems But what about SAS and other statistics programs?...

3. Unlike SASSi… SAS and other programs like it are big and bulky in terms of maintenance, learning curve, and installation They also cost a bunch. $$$$$$$=bad SASSi is free!!!! (currently) SASSi is simple, easy to learn, and easy to use

4. What can SASSi do? Handles many standard statistical problems such as getting the mean, median, standard deviation, etc. for a set of numbers. Defined as a “vector” in SASSi Supports more complicated statistical problems like regressions, distributions, etc. Graphical output.

5. What SASSi looks like Double b; Vector a=[1,1,2,3,5,8]; b=mean(a); print(“The mean of a is: ”); print(b); plot(bar,a);

6. More Samples SASSi allows users to define their own procedure calls Example: procedure Vector foo( Double sheep, Double cow ) { Double dog = sheep*cow; sheep = sheep+1; Vector animals=[sheep, cow, dog]; //etc… return animals; }

7. SASSi grammar (1) Types of data bool: Boolean values that can either be true or false (and True/False and TRUE/FALSE) int: standard 32-bit integers double: 64-bit IEEE double floating-point format string: a string of characters procedure: a user defined procedure vector: an M by 1 vector of doubles Expressions - Very similar to C: Primary expression: Identifiers, constants, procedure calls, and access to vector types Arithmetic expressions: “+”, “-”, “*”, “/” Relational expressions: “ =”, “==”, “ ”, and “<>”

8. SASSi grammar (2) Constants implemented by: const int a = 3;. xconst Include statement: include ;

9. SASSi grammar (3) Statements Assignments Direct assignment in the form: left-valued expression = right-valued expression; Conditional Statements if( relational expression) {statement} else {statement} For Loops for( assignment ; relation expression ; action) {statement}

10. SASSi built-in procedures Basic statistic methods: mean, median, stdDev, etc… Dealing with vectors: sort, range, union, intersect, etc… Distributions: normal, standard, geometric, etc… Regression: linear

11. SASSi Plotting SASSi supports five built-in graphing functions: Bar Pie Chart Line Error Curve

12. SASSi printing Printing variables (Doubles, Int, and Vector) print(v); Printing strings print(“Who knows why you name something foo?”);

13. SASSi implementation ANTLR Interm. Code AST Tree Tokens*.ssi file LEXERPARSER AST WALKER CODE GENE- RATOR Java Bytecode

14. SASSi Summary SASSi is an efficient, small, FREE, statistics language Expandable with user procedures/plots: So even though we didn’t include Poisson distributions, someone could include it in the future… Enough functionality for a base of statistics

15. Lessons Learned Not sticking to your schedule is bad Meeting twice a week is far more effective and comforting than just once Don’t try to implement all statistics functions, or all of C Get feedback from your TA. They’re there to help, and have been there before Think big, build small Decide if what you think is a language would be better off as a program. If so, don’t try to implement it as a language

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