dictionary: update README

Author: ldanko

easyfix-dictionary/README.md

@@ -1,78 +1,63 @@
 # easyfix-dictionary
 
-A Rust library for parsing and representing FIX (Financial Information Exchange) protocol dictionaries.
+Parses FIX XML specifications into Rust data structures for inspection and code
+generation.
 
-## Overview
-
-The `easyfix-dictionary` crate provides functionality to parse XML-based FIX protocol specifications into Rust structures. It supports:
+Part of the [easyfix](https://github.com/ldanko/easyfix) FIX engine.
 
-- Different FIX protocol versions
-- Component and group membership
-- Field definitions with data types
-- Message specifications and categorization
+## Overview
 
-## Features
+The dictionary represents the FIX protocol structure:
 
-- XML parsing of standard FIX dictionary formats
-- Rich type representation of FIX protocol components
-- Support for field types, message types, and component hierarchies
+- **Fields** — data elements with types and possible enumerated values
+- **Components** — reusable groups of fields
+- **Groups** — repeating sets of fields or components
+- **Messages** — message types composed of fields, components, and groups
 
 ## Usage
 
-### Basic Usage
-
 ```rust
-use easyfix_dictionary::{DictionaryBuilder, Version};
-use std::path::Path;
+use easyfix_dictionary::DictionaryBuilder;
 
-// Parse a standard FIX dictionary
 let dictionary = DictionaryBuilder::new()
     .with_fix_xml("path/to/FIX50SP2.xml")
     .with_strict_check(true)
     .build()
     .expect("Failed to parse dictionary");
 
-// Access field definitions
 if let Some(field) = dictionary.field_by_name("BeginString") {
-    println!("Field number: {}", field.number);
+    println!("Field number: {}", field.number());
 }
 
-// Access message definitions
 if let Some(message) = dictionary.message_by_name("Heartbeat") {
     println!("Message type: {}", message.msg_type());
 
-    // Iterate through message members
     for member in message.members() {
-        println!("Member: {}, Required: {}", member.definition().name(), member.required());
+        println!("  {}, required: {}", member.name(), member.required());
     }
 }
 ```
 
-### Working with Modern FIX (FIXT)
+### FIXT (FIX 5.0+)
+
+FIX 5.0+ splits the protocol into transport (FIXT) and application layers.
+Provide both XML files and use `subdictionary()` to access the application
+layer:
 
 ```rust
 use easyfix_dictionary::{DictionaryBuilder, Version};
 
-// Parse FIXT1.1 with application dictionaries
 let dictionary = DictionaryBuilder::new()
     .with_fixt_xml("path/to/FIXT11.xml")
     .with_fix_xml("path/to/FIX50SP2.xml")
     .build()
     .expect("Failed to parse dictionary");
 
-// Accessing the application-level subdictionary
-if let Some(app_dict) = dictionary.subdictionary(Version::FIX50SP2) {
-    // Use app_dict for application messages
+if let Some(app) = dictionary.subdictionary(Version::FIX50SP2) {
+    // application-level messages and fields
 }
 ```
 
-## Dictionary Structure
-
-The FIX dictionary consists of:
-
-- **Fields**: Individual data elements with types and possible enum values
-- **Components**: Reusable groups of fields
-- **Groups**: Repeating sets of fields or components
-- **Messages**: Specific message types composed of fields, components, and groups
+## License
 
-Each element is linked through references, creating a comprehensive representation of the FIX protocol.
+MIT