Python_Interpreter

Object

The project is built based on UIUC CS-421 MP2 (https://github-dev.cs.illinois.edu/cs421-su21/release.git)

Running Code

Install Haskell: https://www.haskell.org/platform/

To run the interpolator, start GHCi with stack ghci. From here, run REPL by calling main.

Type Python commands under Python REPL:

Python>

Use exit() or cmd + c to quit the interpolator.

To test the interpolator use the embedded test, use the following command:

$ stack test

To check all the unit and property test been implemented, it is recommended to use the following command:

$ stack test interpreter\:test\:friendly-test

The friendly test spec can be found in test/friendly/FriendlySpec.hs.

Interpolator Functions

Constants

Recognizable constants include

• integer (both positive and negative)
• double (both positive and negative)
• string (the combination of letters, numbers, marks, punctuation, symbols and spaces, excluding double quote ")

Variables

Assign a constant to a variable The variable name should start with a letter or a underscore. The latter part of the variable name can be letter, number, or underscore.

Python> a = 3

Python> print(a)
3

Basic Operations

Arithmetic Opeartions

Arithmetic operations (+, -, * and /) for integer and double values.

Bool Operations

Bool operations (and, or and not) for bool values (True and False)

Comparison Opeartions

Comparison operations (<, >, <=, >=, /=, ==) for integer and double values.

Python Built-in Functions

abs(x)

Return the aboslute value of a number.

Python> abs(-4)
4
Python> abs(-4.1-9.0)
13.1

bool(x)

Return a Boolean value. x is converted using the standard truth testing procedure.

Python> bool(3.2)
True
Python> bool(-1)
True
Python> bool(0)
False
Python> bool(0.0)
False
Python> bool("ab")
True
Python> bool(True)
True
Python> bool(False or True)
True
Python> bool(not False)
True

chr(i)

Return the string representing a character whose Unicode code point is the integer i.

Python> chr(97)
'a'
Python> chr(45)
'-'

eval(expression)

Evaluate the value of the expression.

Python> eval(1+1)
2
Python> a=4

Python> eval(a+2)
6

print()

Print string or value of an expression given in the argument.

Python> a="Test"

Python> print(a)
"Test"

round(number, ndigits)

Return number rounded to ndigits precision after the decimal point.

Python> round(-8.021,2)
-8.02

To-do

Expression statement

When input an expression, such as a variable expression, display its value. Now it cannot be realized, because an expression statement could be interpolated as a set statement.

Integer and double operations

Currently, the arithmetic and comparison operations require the two operators to be of the same type (int or doulbe). Need to extend to accept mixed data types.