charAnalyzer -- a lexical analyzer that provides characters from a string one at a time

i1 : a = charAnalyzer "abc"

o1 = a

o1 : FunctionClosure

i2 : peek a()

o2 = (0, "a")

i3 : peek a()

o3 = (1, "b")

i4 : peek a()

o4 = (2, "c")

i5 : peek a()

o5 = null

i6 : (constParser "abc" : charAnalyzer) "abc"

o6 = abc