push!

Usage

push!(c, s)

Signature

push!:

(Character,%) $\to$ ()

Parameter	Type	Description
c	Character	a character
s	%	a stream

Returns

Pushes the character $c$ back onto $s$. One character of pushback is guaranteed, this function might however fail if it is called too many times on the same stream without intervening read or positionning calls.