yal's Introduction

Yet Another Language

small interpreted language to try out kotlin and ANTLR

it supports:

int, float, string and bool
int to float type aliasing
simple type checks
some binary ops
if, while
I/O

Example

if (3<4) 
    write "condition was true";
else 
    write "condition was false";

if (true) {
    write "inside";
    write "second";
    write "if";
}

int a, b;

while(a < 10) {
 write "a=", a;
 a = a + 1;
}

a = 0;

read b;

while(a < b) {
 write "a=", a, ", b=", b;
 a = a + 1;
}

run

$  ./gradlew run --args path/to/file.yal

instruction set

Instruction	Description
add	binary +
sub	binary -
mul	binary *
div	binary /
mod	binary %
uminus	unary -
concat	binary . - concatenation od strings
and	binary &&
or	binary \|\|
gt	binary >
lt	binary <
eq	binary == - campares two values
not	unary ! - negating boolean value
itof	Instruction takes int value from the stack, converts it to float and returns it to stack.
push T x	Instruction pushs the value x of type T. Where T represents I - int, F - float, S - string, B - bool. Example: push I 10, push B true, push S "A B C "
pop	Instruction takes on value from the stack and discards it.
load id	Instruction loads value of variable id on stack.
save id	Instruction takes value from the top of the stack and stores it into the variable with name id
label n	Instruction marks the spot in source code with unique number n
jmp n	Instruction jumps to the label defined by unique number n
fjmp n	Instruction takes boolean value from the stack and if it is false, it will perform a jump to a label with unique number n
print n	Instruction takes n values from stack and prints them on standard output
read T	Instruction reads value of type T (I - int, F - float, S - string, B - bool) from standard input and stores in on the stack