Editing COMEFROM (section)

===Examples===
The following is an example of a program in a hypothetical [[BASIC programming language|BASIC]] dialect with "<code>COMEFROM</code>" instead of "<code>GOTO</code>".
<syntaxhighlight lang="qbasic">
10 COMEFROM 40
20 INPUT "WHAT IS YOUR NAME? "; A$
30 PRINT "HELLO, "; A$
40 REM
</syntaxhighlight>
This program (hypothetically) works by asking the user for their name, greeting them with the same name, and continuing all over again. The instruction "<code>REM</code>" on line 40 is simply a [[NOP (code)|NOP]] (in this case, a REMark or [[Comment (computer programming)|comment]]) — the "<code>COMEFROM</code>" statement on line 10 causes a branch back to that line when execution reaches line 40, regardless of its contents.

A fully runnable example in Python with the joke <code>'''goto'''</code> module installed (which uses debugger hooks to control program execution) looks like this:
<syntaxhighlight lang="python">
from goto import comefrom, label

comefrom .repeat
name = raw_input("What is your name? ")
if name:
    print("Hello", name)
    label .repeat
print("Goodbye!")
</syntaxhighlight>

This is an implementation in [[Ruby (programming language)|Ruby]] of the Intercal COME FROM statement.
<syntaxhighlight lang="ruby">
$come_from_labels = {}

def label(l)
  if $come_from_labels[l]
    $come_from_labels[l].call
  end
end

def come_from(l)
  callcc do |block|
    $come_from_labels[l] = block
  end
end
</syntaxhighlight>