# Animated Parse Tree
| | |
|---------------|-------------------|
| Author | Ethan Tan |
| Date | 11/12/2021 |
| Language | Python (py) |
## Description
This package is meant to provide a high-level API for programmers to visualise parse trees. The eventual goal is to animate the tokenization (extracting symbols from a string), lexing (formatting the tokens), parsing (building the parse tree) and evaluation (reducing the parse tree).
## Setup
It is extremely easy to integrate this package in your existing projects.
In the command line, run:
```console
pip install animated_parse_tree
```
## Sample Usage
### From Command Line
Then in your terminal/shell, enter:
```console
python -m animated_parse_tree
```
The output should look similar to the following:
```console
Greetings...
"This is a utility program which aims
to show the beauty of parse trees
in a fun and engaging way"
Don't be intimidated :)
It was designed to be easy to use, yet extensible.
Enjoy!
?>
```
Enter 'help' to display the help menu or 'mode' to change your current mode
### From Source Files
Then in your Python source file / Jupyter Notebook, insert:
```python
from animated_parse_tree import ParseTree
# Instantiate Parse Tree Object
t = ParseTree()
# Read a Mathematical String Expression (separated by singular whitespace characters)
t.read('1 + 2 * 3')
# Retrieve the Result
print('<<< Equation >>>')
print(t.expression, '=', t.evaluate(), end='\n\n')
# Display the Parse Tree
print('<<< Parse Tree >>>')
print(str(t))
```
The output in the terminal will look something like this:
```console
<<< Equation >>>
1 + 2 * 3 = 7
<<< Parse Tree >>>
+
/ \
1 *
/ \
2 3
```
## Declaring Custom Operands/Operators
A `Bundle` is simply a list of Operands and/or Operators.
To extend functionality, one simply has to register their own custom operands/operators like so:
```python
# Instantiate Parse Tree Object
t = ParseTree()
# Declare Custom Operand/Operator(s)
op = Operator(symbol='sum', func=lambda *args: sum(args), priority=Priority.PRE, kind='pre', operands=4)
# Register the Custom Operand/Operator(s)
t.register(bundle=[op])
# Use it in Expressions
t.read('sum(0.1, 2.5, 30, 49)')
# Animate all the Processes
t.animate(seconds_per_frame=1.0)
# Display the Parse Tree
print(str(t))
# Evaluate the Expression
print(t.evaluate())
```
## Current Support
* Operands
* Integers (-1, 0, 2345)
* Floats (0.0, 2.5, -0.77)
* Constants (pi, e)
* Operators
* Unary
* Pre-fix (lg, -)
* Post-fix (deg, !)
* Binary
* Pre-fix (log)
* In-fix (+, -, *, /, ^)
* Multi
* Pre-fix (if)
* Parentheses
* Unlimited nesting
### Other Features Supported
* Implicit Operator (default is higher-priority multiplication)
* Operator Overloading (maximum of 2: 1 pre-fix and 1 non-pre-fix)
* Custom Word Operands/Operators (operands/operators whose symbols are lowercase alphabetical characters)
* Custom Symbol Operands/Operators (operands/operators whose symbols are special characters)
## See Also
- [GitHub Source Code](https://github.com/ethanolx/Animated-Parse-Tree-py)
- [Full Documentation](https://github.com/ethanolx/Animated-Parse-Tree-py/wiki)
- [Python Package (PyPI)](https://pypi.org/project/animated-parse-tree)
