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require "./parser.cr"
require "./map.cr"
require "./exactly.cr"
module Parcom
# `AtLeast` is a `Parser` that tries to parser with another parser
# a specific number of times. The results of each successful parse
# are returned in an array. If the number of successes is less than
# the specified number, the parser fails.
class AtLeast(T, V) < Parser(T, Array(V))
@p : Map(T, {Array(V), Array(V)}, Array(V))
# Accepts the number of parsing attempts, and the parser to use.
# If a negative int is given, it is treated as if it were 0.
def initialize(i : Int, p : Parser(T, V))
@p = (Exactly.new(i, p) + Many.new(p)).map do |tup|
tup[0] + tup[1]
end
end
# Tries to parse the given number of times, or more.
def parse(tokens : Tokens(T)) : Result(T, Array(V))
@p.parse(tokens)
rescue ex : ParserFail
raise ParserFail.new("AtLeast: #{ex.message}")
end
end
end
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