This is a simple modular expression evaluator. It uses several components, focusing on the use of JastAdd system, with AST and aspects definition. The scanner class is generated by the JFlex scanner generator tool, and the parser class is generated by the Beaver LALR parser generator tool.
External dependencies are self contained in the tools directory, except
for Ant.
The Jar artifact needs the Beaver runtime to be executed; a simple method to
run Calc is provided in the run.sh script, as described below.
The expressions syntax is very simple, see res/input0.asc for an example.
The prog directory includes a Java driver that prints sequentially the
results for the given expressions, by using the synthesized attribute
result declaratively defined in spec/Result.jrag.
By creating new aspects (.jrag and .jadd files) the translator can be
extended with new functionalities. Furthermore, concrete and abstract syntax
can be extended or modified by editing .jflex, .parser and .ast files
in the spec directory.
The Ant build.xml reflects the most updated features for all external
packages we use; for example it demonstrates how to use JastAddParser
(Beaver preprocessor) and JastAdd (which have currently no built-in Ant
support).
Just run
$ ant
to build a working jar file in the jar directory.
Run
$ ant clean
to clean up the project tree.
If you encounter some problems on Cygwin environment, try to add the -v flag.
We provide a shell script in the top-level directory, run.sh to try it out.
You can use stdin and then send EOF to process, simply running:
$ ./run.sh
Or you can provide an input file, like res/input0.asc and then executing:
$ ./run.sh res/input0.asc