Not work: aliases and generics make matt a dull boy

1 files changed, 44 insertions, 0 deletions

diff --git a/spec/practical/json_spec.cr b/spec/practical/json_spec.cr
new file mode 100644
index 0000000..0b85658
--- /dev/null
+++ b/spec/practical/json_spec.cr
@@ -0,0 +1,44 @@
+require "../spec_helper"
+
+include Parcom
+
+# defining my own JSON alias in case of strange interactions
+# with the built-in type
+alias JSONValue = Nil \
+                | Bool \
+                | Int64 \
+                | Float64 \
+                | String \
+                | Array(JSONValue) \
+                | Hash(String, JSONValue)
+
+def json_null
+  Parser.token_sequence("null".chars).map { |_| nil.as(JSONValue) }
+end
+ 
+def json_value : Parser(Char, JSONValue)
+  Parser.first_of([
+    json_null,
+  ])
+end
+
+describe "example: JSON parsing" do
+  describe "json_null" do
+    it "parses the string 'null' and returns nil when successful" do
+      result = json_null.parse(Tokens.from_string("null"))
+      result.value.should be_nil
+      result.tokens.empty?.should be_true
+
+      expect_raises(ParserFail) { json_null.parse(Tokens.from_string("")) }
+    end
+  end
+
+  describe "json_value" do
+    it "parses null" do
+      result = json_value.parse(Tokens.from_string("null"))
+      result.value.should be_nil
+      result.tokens.empty?.should be_true
+    end
+  end
+end
+