Wiki: Rockstar 2

Printing

Assignment

Unlike Rockstar 1, you can do x=y instead of x = y.

Augmented assignment

In Rockstar 2, var'sXval (short for var is X val) is the equivalent of other languages' var X= val, where X is in +-*/. While this often doesn't save a byte, it can still be useful, since you can't group expressions with () and, in general, it can save over using an auxiliary variable.

Pronouns

Rockstar 2 supports i as a pronoun, even though it's documented obscurely.

Handling ARGV

This is undocumented, but i's initial value is arguments. It's shorter to assign another variable to i if need be than use arguments directly.

Comparisons

Rockstar 2 has undocumented <, >, <= and >= operators, as well as = (= + space, == in other languages) and != (also with a space).

Printing \

\ now acts like any other character. There used to be an issue.

Whitespace

Usually, statements are separated by a newline (or punctuation within ;.!?), and blocks are ended by 2 newlines, for example:

x=1
for n in 5
m=n*3
say m

say x

Top-level statements do not need newlines between them, and if one ends in [0-9"], it can be attached to the one after it with no whitespace at all:

x=1y="hello"z=3for n in 5
m=n*3
say n

Blocks with a single statement inside them can be collapsed into a single line, and doing so removes the need for multiple newlines after them:

for n in 5 say n
for x in 5 for y in 5 if x>y say x*y
say "done"

A single-line block, if at the top level, does not need a trailing whitespace at all:

for n in 5 say n+1say "done"

Nested blocks require multiple newlines to close them, for example:

for n in 5
if n>2
for y in 5
x=n<y
say n+x



say "done"

But you can collapse the block headers onto a single line, so that only 2 newlines are needed to close the block:

for n in 5 if n>2 for y in 5
x=n<y
say n+x

say "done"

If the code ends after a block, you don't have to close it, no matter how nested the block is.

An odd quirk of if-else: Say you want to port this pseudocode to RS2:

n=10
if n<10 {
 x=n*2
 if x>10 { print x }
} else {
 y=n*3
 print y
}

You might try to port it like this, but it would fail because the else would pair to the inner if:

n=10
if n<10
x=n*2
if x>10 say x
else
y=n*3
say y

You can fix this by just adding a space before the else. No idea why:

n=10
if n<10
x=n*2
if x>10 say x
 else
y=n*3
say y

Precedence of ,

The , separator (to form expression lists) can sometimes be used to override precedence and create statements that otherwise wouldn't be possible without intermediate variables. For example, consider

say "Foo"+x at 0+"Baz"

vs

say "Foo"+x at 0,"Baz"

The first example tries to query x for key "0Baz", since + has higher precedence than at. The second one doesn't, because at doesn't accept expression lists, hence its operand is just 0, with the , belonging to the outside expression.

Integer Division

You may be able to save a byte on floor division by using a loop (at the cost of probably a lot of speed).

x=50.y=7.z=x/y.turn down z.say z.
x=50.y=7.for z in 1+x/y 0.say z.

Rounding

Apart from using the built-in turn up, you can round a positive number up by multiplying it with a string and then dividing it by the same string:

x=3.1
x=x*"."/"."
say x

For negative numbers, this will turn the number positive and round it up.

Built-ins

There's not a lot of built-ins, but acquaint yourself really well with the few there are. These include operators, mutations, at, rock/push (push value at end), pop (pop last element, mis-documented) and roll (pop first element). Consider all types of arguments to these as well. Some very nifty tricks arise from their clever usage. Some of them are listed here.