This Parser will always success and return the clone of given output.
parser that success if reached end of input
This Parser will always fail.
Check one character is equal to the given character.
This Parser will use the closure to parse the input.
Check one character is in the given range.
This Parser will compare the input string starts with the given string.
‘string’ may be a iterator returned by ‘chars()’, etc.
string must be cheaply cloneable.
since iterator from ‘chars()’ is borrowed reference to the original string,
it is cheaply cloneable.