|result|
result := String new.
1 to: 10 do: [:n | result := result, n printString, ' '].

I am trying to do or print this code. It prints 'nil' instead of a collection. Its an example from PBE book.

do you know the reason?

although this one's working:

result := String new.
(1 to: 10) do: [:n | result := result, n printString, ' '].

I checked the implementation

Interval>>do: aBlock

"Evaluate aBlock for each value of the interval.

Implementation note: instead of repeatedly incrementing the value

aValue := aValue + step.

until stop is reached,

We prefer to recompute value from start

aValue := start + (index * step).

This is better for floating points accuracy, while not degrading Integer and Fraction speed too much.

Moreover, this is consistent with methods #at: and #size"

| aValue index size |

index := 0.

size := self size.

[index < size]

whileTrue: [aValue := start + (index * step).

index := index + 1.

aBlock value: aValue]

Number>>to: stop do: aBlock

"Normally compiled in-line, and therefore not overridable.

Evaluate aBlock for each element of the interval (self to: stop by: 1)."

[aBlock value: nextValue.

nextValue := nextValue + 1]

any further idea than := value is different from value: