Updated documentation

regex/doc.go

@@ -4,6 +4,8 @@ Package regex implements regular expression search, using a custom non-bracktrac
 The engine relies completely on UTF-8 codepoints. As such, it is capable of matching characters
 from other languages, emojis and symbols.
 
+The API and regex syntax are largely compatible with that of the stdlib's [regexp], with a few key differences (see 'Key Differences with regexp').
+
 The full syntax is specified below.
 
 # Syntax
@@ -55,8 +57,8 @@ POSIX classes (inside normal character classes):
 Composition:
 
 	def				Match d, followed by e, followed by f
-	x|y				Match x or y (prefer longer one)
-	xy|z			Match xy or z
+	x|y				Match x or y (prefer x)
+	xy|z			Match xy or z (prefer xy)
 
 Repitition (always greedy, preferring more):
 
@@ -94,10 +96,11 @@ Lookarounds:
 Numeric ranges:
 
 	<x-y>			Match any number from x to y (inclusive) (x and y must be positive numbers)
+	\<x				Match a literal '<' followed by x
 
 # Key Differences with regexp
 
-The engine and the API differ from [regexp] in a number of ways, some of them very subtle.
+The engine and the API differ from [regexp] in a few ways, some of them very subtle.
 The key differences are mentioned below.
 
 1. Greediness:
@@ -132,7 +135,7 @@ Rather than using primitives for return values, my engine defines two types that
 values: a [Group] represents a capturing group, and a [Match] represents a list of groups.
 
 [regexp] specifies a regular expression that gives a list of all the matching functions that it supports. The
-equivalent expression for this engine is:
+equivalent expression for this engine is shown below. Note that 'Index' is the default.
 
 	Find(All)?(String)?(Submatch)?
 
@@ -140,7 +143,7 @@ equivalent expression for this engine is:
 
 If a function contains 'All' it returns all matches instead of just the leftmost one.
 
-If a function contains 'String' it returns the matched text, rather than the indices.
+If a function contains 'String' it returns the matched text, rather than the index in the string.
 
 If a function contains 'Submatch' it returns the match, including all submatches found by
 capturing groups.
@@ -156,5 +159,20 @@ and the input string:
 
 The 0th group would contain 'xy' and the 1st group would contain 'y'. Any matching function without 'Submatch' in its name
 returns the 0-group.
+
+# Feature Differences
+
+The following features from [regexp] are (currently) NOT supported:
+ 1. Named capturing groups
+ 2. Non-greedy operators
+ 3. Unicode character classes
+ 4. Embedded flags (flags are passed as arguments to [Compile])
+ 5. Literal text with \Q ... \E
+
+The following features are not available in [regexp], but are supported in my engine:
+ 1. Lookarounds
+ 2. Numeric ranges
+
+The goal is to shorten the first list, and expand the second.
 */
 package regex