Update docs.

CHANGELOG.md

@@ -4,16 +4,22 @@ Rhai Release Notes
 Version 1.13.0
 ==============
 
+This version attempts a number of optimizations that may yield small speed improvements:
+
+* Simple operators (e.g. integer arithmetic) are inlined to avoid the overhead of a function call.
+* The tokenizer uses pre-calculated tables (generated by GNU `gperf`) for keyword recognition.
+* A black-arts trick (see `Engine::black_box`) is used to prevent LLVM from optimizing hand-tuned AST node matches back into a lookup table, which messes up branch prediction on modern CPU's.
+
 Bug fixes
 ---------
 
 * Complex indexing/dotting chains now parse correctly, for example: `a[b][c[d]].e`
 * `map` and `filter` for arrays are marked `pure`. Warnings are added to the documentation of pure array methods that take `this` closures.
 * Syntax such as `foo.bar::baz` no longer panics, but returns a proper parse error.
-* Some op-assignment statements, such as `x += y` where `x` and `y` are `char`, now work correctly instead of failing silently.
 * Expressions such as `!inside` now parses correctly instead of as `!in` followed by `side`.
 * Custom syntax starting with symbols now works correctly and no longer raises a parse error.
 * Comparing different custom types now works correctly when the appropriate comparison operators are registered.
+* Some op-assignments, such as `x += y` where `x` and `y` are `char`, now work correctly instead of failing silently.
 * Op-assignments to bit flags or bit ranges now work correctly.
 
 Potentially breaking changes
@@ -30,8 +36,8 @@ Enhancements
 * The functions `min` and `max` are added for numbers.
 * Range cases in `switch` statements now also match floating-point and decimal values. In order to support this, however, small numeric ranges cases are no longer unrolled.
 * Loading a module via `import` now gives the module access to the current scope, including variables and constants defined inside.
-* Some very simple operator calls (e.g. integer add) are short-circuited to avoid the overhead of a function call, resulting in a small speed improvement.
+* Some very simple operator calls (e.g. integer add) are inlined to avoid the overhead of a function call, resulting in a small speed improvement.
-* The tokenizer now uses table-driven keyword recognizers generated by GNU gperf. At least _theoretically_ it should be faster...
+* The tokenizer now uses table-driven keyword recognizers generated by GNU `gperf`. At least _theoretically_ it should be faster...
 * The field `isAnonymous` is added to JSON functions metadata.
 
 

src/tokenizer.rs

@@ -305,7 +305,7 @@ impl fmt::Display for Token {
     }
 }
 
-// Table-driven keyword recognizer generated by GNU gperf on the file `tools/keywords.txt`.
+// Table-driven keyword recognizer generated by GNU `gperf` on the file `tools/keywords.txt`.
 //
 // When adding new keywords, make sure to update `tools/keywords.txt` and re-generate this.
 
@@ -507,7 +507,7 @@ static KEYWORDS_LIST: [(&str, Token); 153] = [
     ("#{", Token::MapStart),
 ];
 
-// Table-driven reserved symbol recognizer generated by GNU gperf on the file `tools/reserved.txt`.
+// Table-driven reserved symbol recognizer generated by GNU `gperf` on the file `tools/reserved.txt`.
 //
 // When adding new reserved symbols, make sure to update `tools/reserved.txt` and re-generate this.
 
@@ -872,7 +872,7 @@ impl Token {
     #[must_use]
     pub fn lookup_symbol_from_syntax(syntax: &str) -> Option<Self> {
         // This implementation is based upon a pre-calculated table generated
-        // by GNU gperf on the list of keywords.
+        // by GNU `gperf` on the list of keywords.
         let utf8 = syntax.as_bytes();
         let len = utf8.len();
         let mut hash_val = len;
@@ -893,8 +893,8 @@ impl Token {
 
         match KEYWORDS_LIST[hash_val] {
             (_, Token::EOF) => None,
-            // Fail early to avoid calling memcmp()
+            // Fail early to avoid calling memcmp().
-            // Since we are already working with bytes, mind as well check the first one
+            // Since we are already working with bytes, mind as well check the first one.
             (s, ref t) if s.len() == len && s.as_bytes()[0] == utf8[0] && s == syntax => {
                 Some(t.clone())
             }
@@ -2312,7 +2312,7 @@ pub fn is_id_continue(x: char) -> bool {
 #[must_use]
 pub fn is_reserved_keyword_or_symbol(syntax: &str) -> (bool, bool, bool) {
     // This implementation is based upon a pre-calculated table generated
-    // by GNU gperf on the list of keywords.
+    // by GNU `gperf` on the list of keywords.
     let utf8 = syntax.as_bytes();
     let len = utf8.len();
     let rounds = len.min(3);
@@ -2333,8 +2333,8 @@ pub fn is_reserved_keyword_or_symbol(syntax: &str) -> (bool, bool, bool) {
     match RESERVED_LIST[hash_val] {
         ("", ..) => (false, false, false),
         (s, true, a, b) => (
-            // Fail early to avoid calling memcmp()
+            // Fail early to avoid calling memcmp().
-            // Since we are already working with bytes, mind as well check the first one
+            // Since we are already working with bytes, mind as well check the first one.
             s.len() == len && s.as_bytes()[0] == utf8[0] && s == syntax,
             a,
             b,