Parser failing with the given message where current position is added.

parse_error ctx e raises a T.Error with a parse error e and last position of ctx.

opt_ p returns None if p fails, else return Some r where r is the result of p.

take_char is a parser returning None is there is no more char, else accept any character c, Angstrom.advance by 1 char and returns Some c.

take_while_upto pred n accepts at most n characters or as long a pred returns true. Returns accepted characters as a string.

Same as take_while_upto but fails if no character is available.

Accept a comment.

ws ctx accepts any number of white spaces or comments.

p1 &&& p2 returns a parser succeeding when p1 and p2 succeed, in any order.

p1 ||| p2 returns a parser accepting values for p1 or p2 or both.

alt_1_2 def1 p1 def2 p2 is the same as (|||) but returns the provided default values for each parser.