From 15e3a96876ca9e8bd67c7408ebcc123c35a1e447 Mon Sep 17 00:00:00 2001
From: Matthew Hall <hallmatthew314@gmail.com>
Date: Thu, 9 Mar 2023 15:39:01 +1300
Subject: Implement Many and Some

---
 spec/parcom_spec.cr | 50 ++++++++++++++++++++++++++++++++++++++++++++++++--
 src/parcom.cr       | 31 +++++++++++++++++++++++++++++--
 2 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/spec/parcom_spec.cr b/spec/parcom_spec.cr
index 937c43c..57c5024 100644
--- a/spec/parcom_spec.cr
+++ b/spec/parcom_spec.cr
@@ -402,10 +402,56 @@ describe Tokens do
   end
 end
 
-pending Many do
+describe Many do
+  p = Many.new(Token.new('a'))
+
+  describe "#parse" do
+    it "returns an empty array if the wrapped parser never succeeds" do
+      tokens = TokenStream.from_string("bb")
+      result = p.parse(tokens)
+
+      result.value.empty?.should be_true
+      result.tokens.should eq(tokens)
+    end
+
+    it "stops parsing when the wrapped parser fails, returns all successes" do
+      tokens = TokenStream.from_string("aaabcd")
+      result = p.parse(tokens)
+
+      result.value.should eq("aaa".chars)
+      result.tokens.should eq(tokens[3..])
+
+      tokens = TokenStream.from_string("aaa")
+      result = p.parse(tokens)
+
+      result.value.should eq("aaa".chars)
+      result.tokens.should eq(tokens[3..])
+    end
+  end
 end
 
-pending Some do
+describe Some do
+  p = Some.new(Token.new('a'))
+  describe "#parse" do
+    it "fails if the wrapped parser never succeeds" do
+      tokens = TokenStream.from_string("")
+      expect_raises(ParserException) { p.parse(tokens) }
+    end
+
+    it "stops parsing when the wrapped parser fails, returns all successes" do
+      tokens = TokenStream.from_string("aaabcd")
+      result = p.parse(tokens)
+
+      result.value.should eq("aaa".chars)
+      result.tokens.should eq(tokens[3..])
+
+      tokens = TokenStream.from_string("aaa")
+      result = p.parse(tokens)
+
+      result.value.should eq("aaa".chars)
+      result.tokens.should eq(tokens[3..])
+    end
+  end
 end
 
 pending Exactly do
diff --git a/src/parcom.cr b/src/parcom.cr
index 760a450..8d7c754 100644
--- a/src/parcom.cr
+++ b/src/parcom.cr
@@ -246,10 +246,37 @@ module Parcom
     end
   end
 
-  class Many
+  class Many(T, V) < Parser(T, Array(V))
+    def initialize(@p : Parser(T, V))
+    end
+
+    def parse(tokens : TokenStream(T)) : Result(T, Array(V))
+      parsed = [] of V
+
+      loop do
+        result = @p.parse?(tokens)
+        if result.nil?
+          break
+        else
+          parsed << result.value
+          tokens = result.tokens
+        end
+      end
+
+      Result.new(tokens, parsed)
+    end
   end
 
-  class Some
+  class Some(T, V) < Parser(T, Array(V))
+    @p : Assert(T, Array(V))
+
+    def initialize(p : Parser(T, V))
+      @p = Many.new(p).assert { |arr| !arr.empty? }
+    end
+
+    def parse(tokens : TokenStream(T)) : Result(T, Array(V))
+      @p.parse(tokens)
+    end
   end
 
   class Exactly
-- 
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