From 0b0b42e2a1fc13c94f0c8721f083aeb01b198bf7 Mon Sep 17 00:00:00 2001
From: Marcel Otto <marcelotto@gmx.de>
Date: Mon, 27 Jun 2022 00:21:03 +0200
Subject: [PATCH] Add :auto_fix for :case_validation option on defvocab

---
 CHANGELOG.md                                  |  6 ++++--
 .../vocabulary/namespace/case_validation.ex   | 11 ++++++++++
 .../namespace/vocabulary_namespace_test.exs   | 21 +++++++++++++++++++
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 66b1979..341f335 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,8 +19,10 @@ The generated namespaces are much more flexible now and compile faster.
 - `RDF.IRI.starts_with?/2` and `RDF.IRI.ends_with?/2` 
 - `RDF.Graph.build/2` now supports the creation of ad-hoc vocabulary namespaces
   with a `@prefix` declaration providing the URI of the namespace as a string
-- the `case_violations` option of `defvocab` now supports custom handler functions,
-  either as an inline function or as a function on a separate module
+- The `case_violations` option of `defvocab` now supports an `:auto_fix` option 
+  which adapts the first letter of violating term accordingly. It also supports
+  custom handler functions, either as an inline function or as a function on a 
+  separate module.
 
 ### Changed
 
diff --git a/lib/rdf/vocabulary/namespace/case_validation.ex b/lib/rdf/vocabulary/namespace/case_validation.ex
index fc601fa..1e78c06 100644
--- a/lib/rdf/vocabulary/namespace/case_validation.ex
+++ b/lib/rdf/vocabulary/namespace/case_validation.ex
@@ -145,6 +145,10 @@ defmodule RDF.Vocabulary.Namespace.CaseValidation do
     terms_and_ignored
   end
 
+  defp do_handle_case_violations(terms_and_ignored, violation_groups, :auto_fix, base_iri) do
+    do_handle_case_violations(terms_and_ignored, violation_groups, &auto_fix_term/2, base_iri)
+  end
+
   defp do_handle_case_violations(terms_and_ignored, violation_groups, fun, base_iri)
        when is_function(fun) do
     {alias_violations, term_violations} =
@@ -209,4 +213,11 @@ defmodule RDF.Vocabulary.Namespace.CaseValidation do
   defp case_violation_warning(:lowercased_alias, term, _, _) do
     IO.warn("lowercased alias '#{term}' for a non-property resource")
   end
+
+  defp auto_fix_term(:property, term) do
+    {first, rest} = String.next_grapheme(term)
+    {:ok, String.downcase(first) <> rest}
+  end
+
+  defp auto_fix_term(:resource, term), do: {:ok, :string.titlecase(term)}
 end
diff --git a/test/unit/vocabulary/namespace/vocabulary_namespace_test.exs b/test/unit/vocabulary/namespace/vocabulary_namespace_test.exs
index ddba37f..04ee6fc 100644
--- a/test/unit/vocabulary/namespace/vocabulary_namespace_test.exs
+++ b/test/unit/vocabulary/namespace/vocabulary_namespace_test.exs
@@ -139,6 +139,18 @@ defmodule RDF.Vocabulary.NamespaceTest do
       base_iri: "http://example.com/ex#",
       terms: [foo: "bar", baz: "bar", Foo: "Bar", Baz: "Bar"]
 
+    defvocab ExampleWithAutoFixedCaseViolations,
+      base_iri: "http://example.com/ex#",
+      case_violations: :auto_fix,
+      data:
+        RDF.Graph.new([
+          {~I<http://example.com/ex#FooTest>, RDF.type(), RDF.Property},
+          {~I<http://example.com/ex#barTest>, RDF.type(), RDF.Property},
+          {~I<http://example.com/ex#bazTest>, RDF.type(), RDFS.Resource},
+          {~I<http://example.com/ex#baazTest>, RDF.type(), RDFS.Resource}
+        ]),
+      alias: [BaazAlias: :baazTest]
+
     defvocab ExampleWithCustomInlineCaseViolationFunction,
       base_iri: "http://example.com/ex#",
       case_violations: fn
@@ -799,6 +811,15 @@ defmodule RDF.Vocabulary.NamespaceTest do
       end
     end
 
+    test "auto_fix case violations" do
+      alias TestNS.ExampleWithAutoFixedCaseViolations, as: Example
+
+      assert Example.fooTest() == RDF.iri(Example.__base_iri__() <> "FooTest")
+      assert Example.barTest() == RDF.iri(Example.__base_iri__() <> "barTest")
+      assert RDF.iri(Example.BazTest) == RDF.iri(Example.__base_iri__() <> "bazTest")
+      assert RDF.iri(Example.BaazAlias) == RDF.iri(Example.__base_iri__() <> "baazTest")
+    end
+
     test "case violation function (inline)" do
       alias TestNS.ExampleWithCustomInlineCaseViolationFunction, as: Example