Is this a disadvantage of perl?

[Tushar Gokhale]

I just came across a magazine where it did comparison head to head with 
all scripting languages. I'm a beginer in perl.  I couldnt really 
understand what they said so I'm pasting the line on this news group to 
know what exactly this line means

"I can clearly see its disadvantage (convoluted semanitc, absence of 
coroutines, inability to use pipes for connecting loops and subroutines 
like in ksh93) "

This all went over my head but I want to know more on this, atleast 
meaning of this. This was publised in Magazine called "DeveloperIQ 
Issues June 2004" Any comment on this?