Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred).

This is a static analysis: The question is not how often each function is
actually executed at runtime, but how often it is used by the programmer.

Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.

fid='pgm.rex'
cnt.=0
funl=''
Do While lines(fid)>0
  l=linein(fid)
  Do Until p=0
    p=pos('(',l)
    If p>0 Then Do
      do i=p-1 To 1 By -1 While is_tc(substr(l,i,1))
        End
      fn=substr(l,i+1,p-i-1)
      If fn<>'' Then
        Call store fn
      l=substr(l,p+1)
      End
    End
  End
Do While funl<>''
  Parse Var funl fn funl
  Say right(cnt.fn,3) fn
  End
Exit
x=a(3)+bbbbb(5,c(555))
special=date('S') 'DATE'() "date"()
is_tc:
abc='abcdefghijklmnopqrstuvwxyz'
Return pos(arg(1),abc||translate(abc)'1234567890_''"')>0
 
store:
Parse Arg fun
cnt.fun=cnt.fun+1
If cnt.fun=1 Then
  funl=funl fun
Return