Daily Log: Day 9 & 10

• The stack we talked about in the last post is to hold intermediary values generated by our interpreter, e.g.:

 fun echo(n): print n; return n; print echo(echo(1) + echo(2)) + (echo(4) + echo(5)); 

While our interpreter is computing echo(2), it would need some space in memory to hold the output from echo(1) -- That's where the stack comes in. Similarly, it would need to store the output of echo(1) + echo(2), while it computes echo(4) + echo(5). These "produced" values are all pushed in a stack.

• After implementing the stack, noticed that the order of execution of opcodes is not correct in the last output:

== Test Chunk == 0000 122 OP_CONSANT 0 '1.2' 0002 123 OP_CONSANT 1 '456' 0004 124 OP_RETURN 0001 | OP_CONSANT 0 '1.2' 1.2 0003 | OP_RETURN 456 0005 0 OP_CONSANT 0 '1.2' 

The chunk.code should look like this:

OP_CONSTANT 0 // Address of 1.2 in chunk.values OP_CONSTANT 1 // Address of 456 in chunk.values OP_RETURN 

and chunk.values:

1.2 456 

Now, notice that OP_RETURN was executed before the last OP_CONSTANT. Still debugging why.