This is a simple academic project that explores the basics of PLY. This compiler will generate MIPS assembly code that can be run using MARS MIPS Simulator.

• In order to run it, Python 2.7 must be installed.
• Run command: python compiler.py 'input' , where input is the name of the file that contains the source code.
• A file named output.asm will be generated and it can be used in MARS MIPS Simulator.

• All commands end in ;.
• Variables are defined as: x <- 5;.
• Variables are accessible in the current and children's scopes.
• Variables keep the type that was assigned to them when they were initialized.

x <- 5;

if x > 0 then
begin
	z <- 4   x;
	print z;
end;

y <- 3.0;
p <- 2.3 * y;

print p;

x <- 5;

if x > 0 then
begin
	z <- 4   x;
	print z;
	y <- 3.0   x;
end;

p <- 2.3 * y;

print p;

• The first mistake is related with the variable x. Adding 3.0 to x will lead to a type error because x was initialized as an Integer.
• The second mistake is related with scope violation. The variable y was initialized within the if scope and shall only be accessible within the scope where it was created or within the children scopes.

.data
newline: .asciiz "\n"
FALSE: .float 0.0
TRUE: .float 1.0
FL0: .float 3.0
FL1: .float 2.3
li $s0 5
li $t0 0
sgt $t0 $s0 $t0
bge $t0 1 L0
j L1
L0:
li $t0 4
add $s1 $t0 $s0
move $a0 $s1
li $v0 1
syscall
li $v0 4
la $a0 newline
syscall
L1:
lwc1 $f20 FL0
lwc1 $f0 FL1
mul.s $f21 $f0 $f20
mov.s $f12 $f21
li $v0 2
syscall
li $v0 4
la $a0 newline
syscall
li $v0, 10
syscall