Implement AtLeast and AtMost

1 files changed, 49 insertions, 2 deletions

diff --git a/spec/parcom_spec.cr b/spec/parcom_spec.cr
index 713445f..6301c2e 100644
--- a/spec/parcom_spec.cr
+++ b/spec/parcom_spec.cr
@@ -531,10 +531,57 @@ describe Exactly do
   end
 end
 
-pending AtLeast do
+describe AtLeast do
+  letter_a = Token.new('a')
+  tokens = TokenStream.from_string("aaaabcd")
+
+  describe "#parse" do
+    it "fails if there are not enough matching tokens to parse" do
+      p = AtLeast.new(5, letter_a)
+      expect_raises(ParserException) { p.parse(tokens) }
+    end
+
+    it "parses n or more times with the given parser" do
+      p0 = AtLeast.new(0, letter_a)
+      p2 = AtLeast.new(2, letter_a)
+      p4 = AtLeast.new(4, letter_a)
+
+      result0 = p0.parse(tokens)
+      result2 = p2.parse(tokens)
+      result4 = p4.parse(tokens)
+
+      result0.value.should eq("aaaa".chars)
+      result0.tokens.should eq(tokens[4..])
+
+      result2.should eq(result0)
+      result4.should eq(result0)
+    end
+  end
 end
 
-pending AtMost do
+describe AtMost do
+  letter_a = Token.new('a')
+  tokens = TokenStream.from_string("aaaabcd")
+
+  describe "#parse" do
+    it "does not parse more than n times" do
+      p0 = AtMost.new(0, letter_a)
+      p2 = AtMost.new(2, letter_a)
+      p6 = AtMost.new(6, letter_a)
+
+      r0 = p0.parse(tokens)
+      r0.value.empty?.should be_true
+      r0.tokens.should eq(tokens)
+
+      r2 = p2.parse(tokens)
+      r2.value.should eq("aa".chars)
+      r2.tokens.should eq(tokens[2..])
+
+      r6 = p6.parse(tokens)
+      r6.value.should eq("aaaa".chars)
+      r6.tokens.should eq(tokens[4..])
+    end
+  end
 end
 
 pending Between do