The Language of Trees

The packages {@link tree} and {@link treelanguage} defines a "Language of Trees".

This is not a "programming language". It is a "data description" language, more like XML or JSON.

The grammar for this language is,

    Tree ::= '(' String Tree+ ')'
           | String

where {@code '('} and {@code ')'} are literals and {@code Tree+} means one-or-more sub trees.

The files

{@link Tree_Language_Example_0},
{@link Tree_Language_Example_1},
{@link Tree_Language_Example_2},
{@link Tree_Language_Example_3}

give simple examples of how to use the tree language to construct tree data structures.

Instead of writing out all the constructor calls for building an instance of a tree, which makes for fairly complex code, we can instead use a string to describe a tree and then build an instance of the tree from its descriptive string.

The file {@link Tree_Language} defines an interpreter for the tree language.

To build the interpreter, run (double-click)

   build_all_classes.cmd

then run

   build_jar_file.cmd

which builds an executable jar file for the interpreter program.

To run the interpreter jar file, on the command-line run

> Tree_Language.cmd

which runs the interpreter as a REPL (read eval print loop).

The files

script-1.tree
script-2.tree

are "script files" written in the tree language.

To run a script file using the interpreter, on the command-line run

> Tree_Language.cmd  script-1.tree
> Tree_Language.cmd  script-2.tree

You can use the Tree_Language.cmd shell script without opening a command-line window. This makes it easy to run the interpreter's jar file. If you double click on Tree_Language.cmd (after having built the jar file), it will run the interpreter as a REPL. If you drag-and-drop one of the "tree language scripts," script-1.tree or script-2.tree, onto Tree_Language.cmd, it will execute the script file.