Member predicate RegexString :: sourceCharacter
Holds if the ith character of the string is represented between offsets
start (inclusive) and end (exclusive) in the source code of this literal.
This only gives correct results if the literal is written as a normal single-line string literal;
without compile-time concatenation involved.
predicate
sourceCharacter
(
int
pos
,
int
start
,
int
end
)