This is MetaPost, version 1.203 (kpathsea version 3.5.7dev)
**(./trap.mp
\*//*\trap\pass2!
! Missing symbolic token inserted.
<inserted text> 
                 INACCESSIBLE
l.22 ...opmode; outer\; let next=\; delimiters ^~7
                                                  ! fi
! Extra tokens will be flushed.
<to be read again> 
                   !
l.22 ...pmode; outer\; let next=\; delimiters ^~7!
                                                   fi
! Forbidden token found while scanning to the end of the statement.
<inserted text> 
                ;
<to be read again> 
                   \
l.23 next\
          ; % the second pass will now compute silently; the first pass will...


Missing character: There is no c in font trapf!
Missing character: There is no Ü in font trapf!
Missing character: There is no h in font nullfont!
Missing character: There is no i in font nullfont!
hello again^^_
{tracingonline:=1}

f<expr>->let)=];let[=(;show._
(EXPR0)<-xx
{let}
{let}
{show}
>> _1
{showdependencies}
xpart '=-ypart '-0.66667
{qq:=pen}
{showstats}
Memory usage 2372&536 (167 still untouched)
String usage 69&244 (1&6758 now untouched)
{[repeat the loop]}
>> bye
! Isolated expression.
<to be read again> 
                   endtext
l.206 ...pendencies; qq:=q; showstats; bye endtext
                                                  
! Extra tokens will be flushed.
<to be read again> 
                   endtext
l.206 ...pendencies; qq:=q; showstats; bye endtext
                                                  
! Forbidden token found while scanning to the end of the statement.
<inserted text> 
                ;
<to be read again> 
                   endtext
l.206 ...pendencies; qq:=q; showstats; bye endtext
                                                  
{show}
)
*! An expression can't begin with `end'.
<inserted text> 
                0
<to be read again> 
                   end
<*> end
       
>> 0
! A group begun on line 206 never ended.
<to be read again> 
                   end
<*> end
       
{endgroup}
(end occurred when else on line 88 was incomplete)
(end occurred when if on line 37 was incomplete)
(end occurred when elseif on line 22 was incomplete)
(see the transcript file for additional information)
(illegal design size has been changed to 128pt)
(some chardp values had to be adjusted by as much as 0.5pt)
(local label 0:: was missing)
(local label 5:: was missing)
(4 font metric dimensions had to be decreased)
Font metrics written on trap.tfm.
25 output files written: trap.ps .. trap.200
Transcript written on trap.log.