arith-python

Implementation of the arith language in python

Author

Michael David Covarrubias Course CSE210A Programming Languages Assignment Homework 1

Clone Repository

Software Requirements

Documentation

Build Project

Test Software

Clone repository

git clone https://github.com/mdcovarr/arith-python.git

Development Enviornment

Software was developed on CentOS 7

Software requirements

Required software in order to run arith-python software

python3
pip3
pyinstaller

Software requirements on Debian 10

python3 already comes installed with Debian 10 however you will need to install pip3. pip3 will be used to install pyinstaller. You can do this manually via commands

sudo apt-get install python3-pip
sudo pip3 install pyinstaller

Directories and Scripts

arith-python/bin, arith-python/libexec, arith-python/test.sh

Teaching Assistants Testing Software

arith-python/src

Soruce code of implementation

Software documentation

Classs Arith (arith.py)

Class used by the main to run software.

Class InputReader (input_reader.py)

Class used to read from stdin. Once string is read, we validate that there are only valid characters in the input. Else we throw an Exception. If all characters are valid, then we create tokens of input

Example

stdin: '9 * 9 + !'
stdout: Error Invalid Character!

Example

stdin: 4 * 8 + 11
tokens = ['4', '*', '8', '+', '11']

Class Parser (parser.py)

Class used to validate the format of the expression, like not having the expression end with an operator e.g., '+', '-', '*'. And making sure that there are no expressions with invalid format of operators e.g., '9 * - - - 9'. If expression is invalid, an Exception is thrown and the Abstract Syntax Tree is not formed. However, if the expression is validate the Parser class creates the Abstract Syntax Tree.

Example's

'9 * 8 - 2 -'       // Invalid Expression
'9 * - * 10 + 2'    // Invalid Expression
'-1 * -2 + 7'       // Valid Expression

Class Interpreter (interpreter.py)

Class used to interpret the Abstract Syntax Tree and return the result of the expression.

Parent Class ASTNode (ast_node.py)

Abstract class representing a node in the Abstract Syntac Tree (AST).

Child Class ASTInteger (ast_integer.py)

Class representing an integer node in the AST.

Child Class ASTOperator (ast_operator.py)

Class representing an operator node in the AST. An operator such as '+', '-' or '*'.

Class ASTToken (ast_token.py)

Enum class representing all valid tokens

class ASTToken(enum.Enum):
    NONE = 1
    INTEGER = 2
    PLUS = 3
    MINUS = 4
    MULT = 5

Class Expression (expression.py)

Class to encapsulate the expression to be added to the currently built AST. Expression object encapsulates a ASTOperator and a ASTInteger.

Build project

Installing pyinstaller

If you have installed pip3 and python you can install pyinstaller with command:

sudo make init

Build arith executable

executable will be created at arith-python/arith. To make arith executable run command:

make arith

Test software

Once you have built the arith executable to test arith executable with the cse210A-nsgtest repository tests run command:

./test.sh

mdcovarr/arith-python