Add readme section about generating

README.md

@@ -104,6 +104,7 @@ in the freemarker template as a Map of String-keys to String-values.
 `/some/endpoint <- SomeType(foo:String)` is an endpoint declaration. It declares one endpoint that have a request body 
 data type called `SomeType` that has a field called `foo` of the type `String`.
 
+### Data types
 The DSL uses Scala convention of writing data types after the field name separated by a colon. Of course the DSL parser
 does not know anything about java or scala types, as far as it is concerned these are 2 strings and the first one is
 just named field-name and the other string is named field-type.
@@ -111,6 +112,8 @@ just named field-name and the other string is named field-type.
 `Embedded(foo:Bar)` is a `namedTypeDeclaration` which is parsed the same way as the request type above. But isn't tied
 to a specific endpoint.
 
+### Automatically named data types
+
 `/some/other/endpoint <- (bar:Seq[Embedded])` is another endpoint declaration. However this time the request body is
 not named in the DSL. But all datatypes must have a name so it will simply name it after the last path segment and
 tack on the string 'Request' at the end. So the AST till contain a datatype named `endpointRequest` with a field named
@@ -122,9 +125,100 @@ decide to generate in the templates.
 
 The only 'semantic' validation the parser performs is to check that not two types have the same name.
 
+### Reponse data types
+
+It is possible to have an optional response data type declared like so:
+
+`/some/other/endpoint <- (bar:Seq[Embedded]) -> ResponseType(foo: Bar)`
+
+The right pointing arrow `->` denotes a response type, it can be an anonymous data type in which case the parser till 
+name it from the last path segment and add 'Response' to the end of the data type name.
+
 ### DSL config
 
 The only key in the config block the generator looks at is called `ending`, this will be used as the file ending for
 the resulting file of applying the freemarker template.
 
-## Generating
+## Generating
+
+If the parser is successful it will hold the following data in the AST
+
+```java
+public record DocumentNode(
+        Map<String, String> config,
+        List<TypeNode> typeDefinitions,
+        List<EndpointNode> endpoints) {
+}
+```
+
+This will be passed to the freemarker engine as the 'root' data object, meaning you have access to the parts in your freemarker template like this:
+
+```injectedfreemarker
+<#list typeDefinitions as type>
+    This is the datat type name: ${type.name?cap_first} with the first letter capitalized.
+</#list>
+```
+
+That is, you can directly reference `typeDefinitions`, `endpoints` or `config`.
+
+### Config
+
+The config object is simply a String-map with the keys and values unfiltered from the input file. Here is an example
+that writes the value for a config key called 'package'.
+
+`package ${config.package}`
+
+### Data types
+
+These are all the data types the parser have collected, either from explicit declarations, request payloads and response 
+bodies. 
+
+```java
+public record TypeNode(String name, List<FieldNode> fields) { }
+public record FieldNode(String name, String type) { }
+```
+
+Here is an example template that writes the data types as Scala case classes
+```injectedfreemarker
+object Protocol:
+<#list typeDefinitions?sort as type>
+    case class ${type.name?cap_first}(
+    <#list type.fields as field>
+        ${field.name} : ${field.type},
+    </#list>
+    )
+</#list>
+```
+
+### Endpoints
+
+The parser will collect the following data for endpoint declarations
+
+```java
+public record EndpointNode(
+	PathsNode paths,
+	String inputType,
+	Optional<String> outputType) {}
+
+public record PathsNode(List<String> paths) {}
+```
+
+This is an example that will write out the endpoints with the path first, then the Input data type, then the optional 
+Output data type.
+
+```injectedfreemarker
+<#list endpoints as endpoint>
+    <#list endpoint.paths.paths>
+    <#items as segment>/${segment}</#items>
+    Input:
+        ${endpoint.inputType?cap_first}
+    Output:
+    <#if endpoint.outputType.isPresent()>
+        ${endpoint.outputType.get()?cap_first}
+    <#else>
+        Not specified
+    </#if>
+    </#list>
+
+</#list>
+```

endpoints-templates/endpoints-list.ftl

@@ -0,0 +1,14 @@
+<#list endpoints as endpoint>
+    <#list endpoint.paths.paths>
+    <#items as segment>/${segment}</#items>
+    Input:
+        ${endpoint.inputType?cap_first}
+    Output:
+    <#if endpoint.outputType.isPresent()>
+        ${endpoint.outputType.get()?cap_first}
+    <#else>
+        Not specified
+    </#if>
+    </#list>
+
+</#list>