From 6f93f16468d83b84ea386fcf74666a89e80bc704 Mon Sep 17 00:00:00 2001
From: Matthew Hall <hallmatthew314@gmail.com>
Date: Sat, 11 Mar 2023 00:54:33 +1300
Subject: Implement SepBy

---
 spec/parcom_spec.cr | 48 ++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 10 deletions(-)

(limited to 'spec/parcom_spec.cr')

diff --git a/spec/parcom_spec.cr b/spec/parcom_spec.cr
index d67f19a..9b70c2e 100644
--- a/spec/parcom_spec.cr
+++ b/spec/parcom_spec.cr
@@ -637,15 +637,6 @@ describe Between do
   end
 end
 
-pending StopAt do
-end
-
-pending StopAfter do
-end
-
-pending StopIf do
-end
-
 describe FirstOf do
   tokens = TokenStream.from_string("abcd")
   letter_a = Token.new('a')
@@ -680,6 +671,43 @@ describe FirstOf do
   end
 end
 
-pending SepBy do
+describe SepBy do
+  describe "#parse" do
+    letter_a = Token.new('a')
+    comma = Token.new(',')
+    tokens = TokenStream.from_string("a,a,a,a")
+
+    it "fails if no elements can be parsed" do
+      p = SepBy(Char, Char, Char).new(comma, comma)
+      expect_raises(ParserException) { p.parse(tokens) }
+    end
+
+    it "succeeds if only one element can be parsed" do
+      t1 = TokenStream.from_string("a")
+      t2 = TokenStream.from_string("a,")
+      p = SepBy(Char, Char, Char).new(letter_a, comma)
+
+      result = p.parse(t1)
+      result.value.should eq(['a'])
+      result.tokens.should eq(t1[1..])
+
+      result = p.parse(t2)
+      result.value.should eq(['a'])
+      result.tokens.should eq(t2[1..])
+    end
+
+    it "parses 1 element, then 0 or more (sep >> element)" do
+      p = SepBy(Char, Char, Char).new(letter_a, comma)
+
+      result = p.parse(tokens)
+      result.value.should eq("aaaa".chars)
+      result.tokens.empty?.should be_true
+
+      # drop last char in tokens, should parse three elements
+      result = p.parse(tokens[..5])
+      result.value.should eq("aaa".chars)
+      result.tokens.should eq(TokenStream.from_string(","))
+    end
+  end
 end
 
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