AST example: CalcTree

This example shows

how specify object-oriented ASTs by means of a JastAdd abstract grammar (in an .ast file)
how to use JJTree to build such ASTs in the parser (specified in the .jjt file)
how to modularize computations on the AST using two different techniques:
- intertype declarations (programmed as JastAdd .jadd files)
- the visitor pattern (programmed as subclasses to the Visitor class generated by JJTree)

Files:

CalcTree.ast - the abstract grammar
CalcParser.jjt - the JJTree specification with AST-building actions
DumpCalcExpression.java - a main program which reads a calculator program from standard input, parses the program, and prints the AST on standard output.
ComputationByAOP.java - a main program which analyses a calculator program and reports if it contains a certain kind of statement (the "ask user" statement). The program is implemented by means of intertype declarations (in a .jadd file). See InteractiveComputation.jadd.
ComputationByVisitor.java - another main program which computes the same thing, but by means of a visitor. See InteractiveComputationVisitor.java.
build.xml - the build file used by ant:
- ant -
  - runs JastAdd to generate AST classes with code weaved in from the .jadd files
  - runs JJTree to generate the .jj-file instrumented with AST-building actions
  - runs JavaCC to generate the parser (and scanner)
  - runs a java compiler to compile all java code
- ant gen - the same as above but without compiling. Suitable when running from Eclipse rather than from the command line.
- ant test - runs all main programs on a number of test programs and checks the output against result files containing the expected results
- ant clean - removes generated files
Test cases (with expected results) are organized in two subdirectories
- DumpTests.java - junit test for tests in DumpTests folder
- DumpTests - for testing DumpCalcExpression
  - allsyntax.calc and allsyntax.res
  - associativetest.calc and associativetest.res
- ComputationTests.java - junit tests of ComputationByAOP and ComputationByVisitor
- ComputationTests - for testing CalcInteractive1 and CalcInteractive2
  - interactiveExample.calc and interactiveExample.res
  - nonInteractiveExample.calc and nonInteractiveExample.res
CalcTree.zip - all the files listed above. Go to the directory where you want the CalcTree folder and extract with:
```
  unzip CalcTree.zip
   
```

You can experiment with the example by copying it to your own directory and using the ant commands.

Instead of using ant you can also run manually as follows:

Create the directory in which generated files will be placed (both AST classes and parser classes will be placed there)
```
  mkdir AST
```
Run JastAdd to generate the AST classes (do "java -jar tools/jastadd2.jar --help" for an explanation of the options).
```
  java -jar tools/jastadd2.jar --package=AST --jjtree --grammar=CalcParser *.ast *.jadd
```

Run JJTree to generate the .jj file and Java classes for tree building.

  java -classpath tools/javacc.jar jjtree -OUTPUT_DIRECTORY=AST -STATIC=false -VISITOR=true -NODE_PACKAGE="AST" CalcParser.jjt

Run JavaCC to generate the Java classes for the parser (and scanner):

  java -classpath tools/javacc.jar javacc -OUTPUT_DIRECTORY=AST -STATIC=false AST/CalcParser.jj

Compile all java files

  javac -classpath tools/junit.jar:. *.java AST/*.java

Examples for running the main programs

  java DumpCalcExpression DumpTests/allsyntax.calc
  java ComputationByAOP ComputationTests/interactiveExample.calc
  java ComputationByVisitor ComputationTests/interactiveExample.calc

Run all the tests
```
  java -cp tools/junit.jar:. TestAll
```

Last modified: Feb 3, 2006 (Görel Hedin)