Second rewrite attempt, this one should work, monkaS

1 files changed, 33 insertions, 0 deletions

diff --git a/src/__OLD_parcom/sequence.cr b/src/__OLD_parcom/sequence.cr
new file mode 100644
index 0000000..6a05cde
--- /dev/null
+++ b/src/__OLD_parcom/sequence.cr
@@ -0,0 +1,33 @@
+require "./parser.cr"
+
+module Parcom
+  # `Sequence` is a `Parser` that combines multiple parsers and
+  # tries to parse all of them in succession. If all of the parsers
+  # succeed, the values parsed are returned in an array, in the order
+  # they were parsed in. If any of the parsers fail,
+  # the `Sequence` also fails.
+  class Sequence(T, V) < Parser(T, Array(V))
+    # Accepts the parsers to use.
+    def initialize(@ps : Iterable(Parser(T, V)))
+    end
+
+    # Tries each parser in order, and returns their results.
+    # Fail if any of the wrapped parsers fail.
+    # TODO: this can probably be optimised more for Arrays
+    # TODO: might be better to use #zip
+    def parse(tokens : Tokens(T)) : Result(T, Array(V))
+      parsed = [] of V
+
+      @ps.each do |p|
+        r = p.parse(tokens)
+        parsed << r.value
+        tokens = r.tokens
+      end
+
+      Result.new(tokens, parsed)
+    rescue ex : ParserFail
+      raise ParserFail.new("Sequence: #{ex.message}")
+    end
+  end
+end
+