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LAB 11 - ciLisp Final Project COMP-232 Programming Languages TASK 3 In this task, you will add typecasting functionality to the let_elem, allowing symbols to have a specified type

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LAB 11 - ciLisp Final Project

COMP-232 Programming Languages

TASK 3

In this task, you will add typecasting functionality to the let_elem, allowing symbols to have a specified type.

 

The new additions to the grammar are:

let_elem ::= ( TYPE SYMBOL s_expr )

 

TYPE ::= "int" | "double"

 

You'll need to expand the SYMBOL_TABLE_NODE to include a type field (storing a NUM_TYPE). You should also expand the NUM_TYPE enum to include a NO_TYPE element, for when SYMBOL_TABLE_NODEs are created without typecasting. Numbers with NO_TYPE should never exist; NO_TYPE is solely a placeholder to say "this variable will take whatever type it was assigned, without casting it", i.e. the variable will be duck-typed.

When evaluating symbols, you'll need to take their type into consideration; the AST_NUMBER (which should be stored in the SYMBOL_TABLE_NODE's referenced value AST_NODE after evaluation) should be stored with typecasting applied. If this causes a loss of precision (i.e. if a double is cast as an integer) then a warning should be printed stating that this is the case.

This task should be quick; if you find you need to make more than a few simple changes, you're likely overthinking it!

The sample run below coincides with the provided task 3 test input. This only tests the basic new functionality, and does not ensure that it is well integrated with the old functionality. You should create more complex test cases, testing the entire project so far.

> ((let (int a 1.25))(add a 1))

WARNING: Precision loss on int cast from 1.25 to 1.

Integer : 2

 

> ((let (double a 5))(add a 25))

Double : 30.000000

 

> ((let (double $_1 (add 1 2))) (mult $_1 3))

Double : 9.000000

 

> quit

 

Process finished with exit code 0