add doc tag

.gitignore

@@ -20,3 +20,4 @@ packaging/builds
 
 # Theme Liquid docs live at git@github.com:Shopify/theme-liquid-docs.git,
 /data/shopify_liquid/documentation/
+.claude

CLAUDE.md

@@ -0,0 +1,91 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+platformOS Check is a linter and language server (LSP) for platformOS applications. It analyzes Liquid templates, JSON, YAML, and GraphQL files to enforce best practices, identify performance issues, and catch errors. Written in Ruby 3.2+.
+
+## Common Commands
+
+```bash
+# Run all tests (runs against both InMemory and FileSystem storage)
+bundle exec rake test
+
+# Run tests with specific storage (faster for development)
+bundle exec rake tests:in_memory
+bundle exec rake tests:file_system
+
+# Run a single test file
+bundle exec ruby -Itest test/checks/unused_assign_test.rb
+
+# Run linter
+bundle exec rubocop
+
+# Run CLI on a platformOS app
+bin/platformos-check /path/to/app
+
+# Create a new check (generates check, test, and docs files)
+bundle exec rake "new_check[MyCheckName]"
+
+# Update platformOS Liquid documentation
+bundle exec rake download_theme_liquid_docs
+```
+
+## Architecture
+
+### Entry Points
+- `bin/platformos-check` - CLI tool
+- `bin/platformos-check-language-server` - LSP server for IDE integration
+
+### Core Components
+
+**Analyzer** (`lib/platformos_check/analyzer.rb`): Central orchestrator that runs checks. Manages check lifecycle: `analyze_platformos_app()` → `analyze_files()` → `finish()`.
+
+**App** (`lib/platformos_check/app.rb`): Represents a platformOS application as a collection of typed files (LiquidFile, YamlFile, GraphqlFile, etc.). Uses regex patterns to categorize files into pages, partials, forms, layouts, etc.
+
+**Check System** (`lib/platformos_check/check.rb`): Base class for all checks. Checks inherit from `LiquidCheck`, `YamlCheck`, or `HtmlCheck` and implement visitor methods like `on_document`, `on_assign`, `on_variable_lookup`, `on_end`.
+
+**Storage Layer**: Abstract interface with two implementations:
+- `FileSystemStorage` - Reads from disk (production)
+- `InMemoryStorage` - For language server and tests
+
+**Language Server** (`lib/platformos_check/language_server/`): LSP implementation with completion providers, hover providers, code action providers, and diagnostics engine.
+
+### Visitor Pattern
+Checks use a visitor pattern for AST traversal. The `LiquidVisitor` walks Liquid AST and calls check methods (`on_assign`, `on_graphql`, etc.).
+
+### Reporting Offenses
+```ruby
+add_offense(message, node:) do |corrector|
+  corrector.replace(node.range, "fixed code")
+end
+```
+
+## Creating a New Check
+
+1. Run `bundle exec rake "new_check[CheckName]"`
+2. Implement the check in `lib/platformos_check/checks/check_name.rb`
+3. Add configuration to `config/default.yml`
+4. Write tests in `test/checks/check_name_test.rb`
+
+## Debugging
+
+```bash
+# Enable debug mode (disables timeouts, enables --profile flag)
+export PLATFORMOS_CHECK_DEBUG=true
+
+# Language server logging
+export PLATFORMOS_CHECK_DEBUG_LOG_FILE=/tmp/platformos-check-debug.log
+```
+
+## Configuration
+
+Project configuration is in `.platformos-check.yml`. Default check settings are in `config/default.yml`.
+
+Checks can be disabled in code:
+```liquid
+{% # platformos-check-disable CheckName %}
+...
+{% # platformos-check-enable CheckName %}
+```

data/platformos_liquid/documentation/latest.json

@@ -1,2 +1,2 @@
 
-{"revision":"fdd40db2e085f4472f7adad7966d9b760d82ac79"}
+{"revision":"be109cad315451c536817c95f81a5824dd77f9fe"}

lib/platformos_check.rb

@@ -49,6 +49,7 @@
 require_relative "platformos_check/tags/background"
 require_relative "platformos_check/tags/cache"
 require_relative "platformos_check/tags/context"
+require_relative "platformos_check/tags/doc"
 require_relative "platformos_check/tags/export"
 require_relative "platformos_check/tags/form"
 require_relative "platformos_check/tags/function"

lib/platformos_check/tags.rb

@@ -36,6 +36,7 @@ def register_tags!
         register_tag('content_for', ContentFor)
         register_tag('context', Context)
         register_tag('context_rc', Context)
+        register_tag('doc', Doc)
         register_tag('export', Export)
         register_tag('form', Form)
         register_tag('function', Function)

lib/platformos_check/tags/doc.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module PlatformosCheck
+  module Tags
+    class Doc < Liquid::Block
+      def initialize(tag_name, markup, options)
+        super
+        raise Liquid::SyntaxError, "Syntax Error in 'doc' - doc tag does not accept any parameters" unless markup.strip.empty?
+      end
+    end
+  end
+end

test/tags/doc_tag_test.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+module PlatformosCheck
+  module Tags
+    class DocTagTest < Minitest::Test
+      def test_doc_tag_without_parameters
+        offenses = analyze_platformos_app(
+          "app/views/pages/index.liquid" => <<~END
+            {% doc %}
+              This is a documentation block.
+              It can contain notes about the code.
+            {% enddoc %}
+          END
+        )
+
+        assert_offenses("", offenses)
+      end
+
+      def test_doc_tag_with_parameters_fails
+        offenses = analyze_platformos_app_without_raise(
+          PlatformosCheck::SyntaxError.new,
+          "app/views/pages/index.liquid" => <<~END
+            {% doc arg: 1 %}
+              Documentation
+            {% enddoc %}
+          END
+        )
+
+        assert_equal(1, offenses.size)
+        assert_match(/syntax error/i, offenses.first.message.downcase)
+      end
+
+      def test_doc_tag_with_content
+        offenses = analyze_platformos_app(
+          "app/views/pages/index.liquid" => <<~END
+            {% doc %}
+              # API Documentation
+              This function handles user authentication
+              Parameters:
+              - email: String
+              - password: String
+            {% enddoc %}
+          END
+        )
+
+        assert_offenses("", offenses)
+      end
+    end
+  end
+end