An underscore (_) can be placed anywhere, where comment can be placed. Like the comment, it is ignored. It is just a separator, which can be useful in some situations.

Names Separator

Underscore can be used to separate subsequent names inside a phrase. The following code will place two new line characters after the "Hello" string:

Print "Hello" nl _nl

The underscore is required here, because without it the two subsequent nl words will be considered a single name, which will raise a compile time error:

Print "Hello" nl nl ~~ **Error**: `print` phrase can not recognize a
                    ~~ `nl nl` symbol.

Line Continuation

An underscore can be used to continue an expression or statement to the next line.

The line is considered a continuation of preceding one if it starts with an underscore:

A * b +

Only spaces can precede the underscore on the same line. No comments allowed. But comments allowed between the line and its continuation:

  A + ~~ comment 1
  Block comment
  between the lines
  _ ~~Inline comment after underscore~~ b