Add domain glossary (CONTEXT.md) (#2016)

Author: DerManoMann

.gitignore

@@ -15,3 +15,4 @@ vendor/
 .idea/
 .phpstan/
 /.phpunit.cache/test-results
+/.claude/settings.local.json

CONTEXT.md

@@ -0,0 +1,93 @@
+# swagger-php
+
+A PHP library that generates OpenAPI specification documents from PHP source code
+by scanning annotations (attributes and docblocks) and processing them into a
+complete spec.
+
+## Language
+
+### Core Concepts
+
+**Annotation**:
+An OpenAPI specification element declared as a PHP 8+ attribute or legacy docblock comment on a class, method, or property.
+_Avoid_: Attribute (too narrow), decorator, metadata
+
+**Analysis**:
+The aggregate result of scanning source code — contains all discovered annotations and structural definitions, before processing.
+_Avoid_: Result, scan output
+
+**Context**:
+Nested metadata describing where an annotation was found in the source hierarchy (file, namespace, class, method, property).
+_Avoid_: Location, position
+
+**Generator**:
+The orchestrator that coordinates scanning, processing, and output — it generates an OpenAPI spec from annotations, not code from a spec.
+_Avoid_: Builder, compiler
+
+**Processor**:
+A single transformation step in an ordered pipeline that converts raw Analysis into a valid, complete OpenAPI specification.
+_Avoid_: Handler, middleware, transformer
+
+### Annotation Lifecycle
+
+**Unmerged**:
+An annotation that has been discovered but not yet incorporated into the target OpenAPI root object.
+_Avoid_: Pending, orphaned
+
+**Merge**:
+Incorporating an annotation into its correct position within the OpenAPI object tree, guided by the nesting map.
+_Avoid_: Combine, attach
+
+**Augment**:
+Filling in missing annotation fields with values inferred from code (e.g. deriving a schema type from a PHP type hint).
+_Avoid_: Enrich, hydrate
+
+**Expand**:
+Resolving PHP inheritance (classes, interfaces, traits, enums) by copying parent annotations into child schemas.
+_Avoid_: Inherit, flatten
+
+### Structural Concepts
+
+**Nesting**:
+The declarative parent-child mapping (`$_nested`) that defines which annotation types can belong inside other annotation types — distinct from PHP class inheritance.
+_Avoid_: Hierarchy (ambiguous with class hierarchy)
+
+**Component**:
+A reusable named definition stored in `#/components/` and referenced via `$ref` elsewhere in the spec.
+_Avoid_: Shared schema, template
+
+**Ref**:
+A JSON Pointer (`$ref`) linking to another part of the spec, resolved by processors into `#/components/...` paths.
+_Avoid_: Link (means something else in OpenAPI), pointer
+
+### Scanning
+
+**Analyser**:
+Reflects on PHP source files to discover annotations and produce an Analysis.
+_Avoid_: Scanner (too narrow — TokenScanner is a sub-component), parser
+
+**AnnotationFactory**:
+Creates annotation objects from discovered PHP attributes or docblock comments during analysis.
+_Avoid_: Builder, constructor
+
+## Relationships
+
+- A **Generator** uses an **Analyser** to produce an **Analysis**
+- An **Analysis** contains **Annotations**, each carrying a **Context**
+- **Processors** run sequentially on an **Analysis**, first **merging** unmerged annotations, then **expanding** inheritance, then **augmenting** missing fields
+- **Nesting** defines where an **Annotation** can be merged within the OpenAPI tree
+- A **Component** is an **Annotation** that has been merged into `#/components/` and is reachable by **Ref**
+
+## Example dialogue
+
+> **Dev:** "I added a `@OA\Schema` on a class but it's not appearing in the output."
+> **Domain expert:** "Is it still **unmerged**? Check that the **nesting** map allows it to be **merged** into Components, and that a **processor** hasn't filtered it out."
+
+> **Dev:** "Why does the child class schema include the parent's properties?"
+> **Domain expert:** "That's **expansion** — the ExpandClasses **processor** copies parent **annotations** into the child during the pipeline."
+
+## Flagged ambiguities
+
+- "generate" — resolved: reserve for the full end-to-end pipeline (`Generator::generate()`). Use **analyse** for the discovery phase and **serialize** for producing JSON/YAML output.
+- "merge" — resolved: reserve for tree-placement (moving an annotation into its correct position in the OpenAPI object). Combining multiple annotations' fields into one (e.g. Properties into a Schema) is part of **augment**.
+- "nested" — resolved: use **nesting map** when referring to the `$_nested` declaration. Use **enclosing** when talking about the physical source code structure (file, class, method) that Context tracks.

docs/guide/under-the-hood.md

@@ -4,8 +4,7 @@
 
 - The `Generator` iterates over the given sources (Symfony `Finder`, file/directory list, etc.)
 - The configured analyser (`AnalyserInterface`) reads the files and builds an `Analysis` object.
-  Default (as of v4) is the `ReflectionAnalyser`. Alternatively, there is the `TokenAnalyser` which was the default in v3.
-- The legacy `TokenAnalyser` was removed in v5.
+  The default is the `ReflectionAnalyser`.
 - The `Analysis` object and its annotations are then processed by the configured processors.
 - If enabled, the analysis/annotations are validated.
 - The root `OpenApi` annotation then contains all annotations and is serialized into YAML/JSON.
@@ -15,7 +14,7 @@
 Each annotation is associated with a unique `Context` instance. This contains details, collected by the parser/analyser,
 about the PHP context where the annotation was found.
 
-Typically, there will be a processor that uses the data to augment/enrich the annotation.
+Typically, there will be a processor that uses the data to augment the annotation.
 
 **Examples of the data collected:**
   - class/interface/trait/enum names