Wrote a grammar that recognizes the statements described below and generated its lexical analyzer and parser. After obtaining the lexical analyzer and the parser, all the action routines needed to evaluate a given python code were written.
Python Interpreter written using Java’s ANTLR library.
a. L=[] (this instruction defines an empty list)
b. L=[val_1, val_2, …] where values can be of different types. The types to be considered in this assignment are integers and strings. For example, L=[‘hello’, 2, ‘world’] defines a list of three elements.
c. L[i] = value assigns a value to the ith element of the list. For example, L[1]=4 modifies the above list to: [‘hello’, 4, ‘world’]
L1 + L2 creates a new list by concatenating L1 and L2. For example,[1, 2]+[‘a’, ’b’, ’c’] creates the list [1, 2, ‘a’, ’b’, ’c’]. Concatenating several lists at once is also supported.
a. L[begin_index:end_index] returns the portion starting at begin_index (inclusive) and ending at end_index (exclusive). For example, the following code would return [’b’,’c’]
L=[‘a’,’b’,’c’,’d’,’e’]
L[1:3]
b. L[begin_index:] returns the portion from begin_index (inclusive) till the end of the list
c. L[:end_index] returns the portion from the beginning of the list till end_index (exclusive)
[for val in list if condition]. It defines a new list containing a subset of the elements in the original list satisfying the condition. Only lists of integers should be supported.
Conditions are restricted to the form: operand1 op operand2 where op is a comparison operator (==, !=, <, <=, >, >=) and each of the operands is either an integer or val. You should also support ‘and’, ‘or’, and ‘not’.
L1 = ['hello', 'everybody', 'from', 'aub'] print(L1)
L2 = ['hello', 55, 'from', L1] print(L2)
L2[2] = ‘to’ print(L2)
L3 = ['333', 33, 3] print(L3)
L4 = ['444', 44, 4] print(L4)
L3 = L1 + L2 print(L3)
L5 = L1 + L2 + L3 + L4 print(L5)
L6 = L5[3:7] print(L6)
L7 = L5[:6] print(L7)
L8 = L5[3:] print(L8)
L9 = [1, 2, 3, 4, 5, 6, 7, 8, 9]
c1=[for x in L9 if (x > 4)] print(c1)
c2=[for x in L9 if (5 == 2)] print(c2)
c3=[for x in L9 if (5 > x)] print(c3)
c4=[for x in L9 if (x == x)] print(c4)
c5=[for x in L9 if not (x == 4)] print(c5)
c6=[for x in L9 if (x != 4)] print(c6)
c7=[for y in L9 if (x != 4)] print(c7)
c8=[for x in L9 if (7 != y)] print(c8)
c10=[for x in L9 if ( ( ((x > 2) and (7 > x)) or (x == 9) ) and (x > 5) )] print(c10)
c11=[for x in L9 if ( ( ((x > 2) and (7 > x)) or not(x == 9) ) and (x > 5) )] print(c11)
c12=[for x in L9 if ( ( not ((x > 2) and (7 > x)) or not(x == 9) ) and (x > 5) ) ] print(c12)
L1 is ['hello', 'everybody', 'from', 'aub']
L2 is ['hello', 55, 'from', L1]
L2 is ['hello', 55, 'to', L1]
L3 is ['333', 33, 3]
L4 is ['444', 44, 4]
L3 is ['hello', 'everybody', 'from', 'aub', 'hello', 55, 'to', L1]
L5 is ['hello', 'everybody', 'from', 'aub', 'hello', 55, 'to', L1, 'hello', 'everybody', 'from', 'aub', 'hello', 55, 'to', L1, '444', 44, 4]
L6 is ['aub', 'hello', 55, 'to']
L7 is ['hello', 'everybody', 'from', 'aub', 'hello', 55]
L8 is ['aub', 'hello', 55, 'to', L1, 'hello', 'everybody', 'from', 'aub', 'hello', 55, 'to', L1, '444', 44]
c1 is [5, 6, 7, 8, 9]
c2 is []
c3 is [1, 2, 3, 4]
c4 is [1, 2, 3, 4, 5, 6, 7, 8, 9]
c5 is [1, 2, 3, 5, 6, 7, 8, 9]
c6 is [1, 2, 3, 5, 6, 7, 8, 9]
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
Unknown variable x. Did you mean y
c7 is []
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
Unknown variable y. Did you mean x
c8 is []
c10 is [6, 9]
c11 is [6, 7, 8]
c12 is [6, 7, 8, 9]