FunctionalLanguage

Implementation of a (really simple) Functional Language with a Stack Virtual Machine, using ANTLR. This project is a case-study for the course "Linguaggi di programmazione e modelli computazionali", Ingegneria e Scienze Informatiche LM, Cesena, UNIBO.

General

The "FunctionalLanguage" (described by the grammar FunctionalLanguage.g) compiles in pseudo-machine code, that is then executed by a pseudo-virtualmachine. The language generated is described by the grammar in StackVirtualMachine.g.

Sample functional language syntax

def INT sommatutti( LIST-OF[INT] l) = 
 if (l==empty) then 0
               else (l.first)+sommatutti( (l.rest) );  

print sommatutti([5,[3,empty]]);
print (5-3+2+3);

/*
 *  Simple var assignment and print
 */
def INT num = 10;
def BOOL state = true;
print num;
print state;

/*
 * Fn INT -> INT
 */
def INT double(INT number) =
if (number == 0) then 0 else number+number;
	
def INT test0 = double(0);
def INT test1 = double(1);
print test0;
print test1;

/*
 * Fn INT -> BOOL
 */
def BOOL isZero(INT number) =
if (number == 0) then true else false;

def BOOL prova0 = isZero(0);
print prova0;

def BOOL prova1 = isZero(1);
print prova1;

/*
 * Fn INT, BOOL -> BOOL
 */
def INT testFn(INT num, BOOL cond) =
if(cond == true) then num else 0;

Sample generated pseudo-machine code

lfp
push -1
push 3
lhp
sw
lhp
push 1
add
sw
lhp
lhp
push 2
add
shp
push 5
lhp
sw
lhp
push 1
add
sw
lhp
lhp
push 2
add
shp
jal sommatutti
print

push 3
push 5
sub
push 2
add
push 3
add
print

...

Type Checking

The type checking has been succesfully implemented, following these steps:

Build the AST
Create and populate a Symbol Table, that stores information about types of each node/leaf.
Use the information stored during the top-down process of syntax-directed translation to perform type checks.

AL333Z/FunctionalLanguage

FunctionalLanguage

General