fixup docs

Author: harendra-kumar

core/src/Streamly/Internal/Data/Parser/Type.hs

@@ -316,44 +316,46 @@ instance Functor (Initial s) where
 -- is used for the next step.
 --
 -- If the result is 'SContinue', the parser driver retains the input in a
--- backtracking buffer, if the parser fails we may have to backtrack. If the
--- result is `SPartial` then the backtracking buffer is released i.e. we cannot
--- backtrack beyond this point in th stream. The parser must ensure that the
--- backtrack position is always after that.
+-- backtracking buffer, in case of failure the parser can backtrack up to the
+-- length of the backtracking buffer. Whenever the result is `SPartial` the
+-- current backtracking buffer is released i.e. we cannot backtrack beyond this
+-- point in the stream. The parser must ensure that the backtrack position is
+-- always within the bounds of the backtracking buffer.
 --
 -- If parser is not yet done, we can use the @extract@ operation on the @state@
 -- of the parser to extract a result. If the parser has not yet yielded a
--- result, the extract fails with a 'ParseError' exception. If the parser
--- yielded a 'Partial' result in the past the latest partial result is
--- returned. Therefore, if a parser yields a partial result once it cannot fail
--- later on.
+-- result, @extract@ fails with a 'ParseError' exception. If the parser yielded
+-- a 'Partial' result in the past then the latest partial result is returned.
+-- Therefore, if a parser yields a partial result once it cannot fail later on.
 --
 -- /Pre-release/
 --
 {-# ANN type Step Fuse #-}
 data Step s b =
         SPartial !Int !s
-    -- ^ @SPartial count state@. The following hold on Partial result:
+    -- ^ @SPartial count state@. The following statements hold on an SPartial
+    -- result:
     --
     -- 1. @extract@ on @state@ would succeed and give a result.
-    -- 2. Input stream position is reset to @current position + count@.
+    -- 2. Input stream position is updated to @current position + count@.
     -- 3. All buffered input before the new position is dropped. The parser can
-    -- never backtrack beyond this position.
+    -- never backtrack before this position.
 
     | SContinue !Int !s
-    -- ^ @SContinue count state@. The following hold on a Continue result:
+    -- ^ @SContinue count state@. The following statements hold on an SContinue
+    -- result:
     --
-    -- 1. If there was a 'SPartial' result in past, @extract@ on @state@ would
-    -- give that result otherwise it may return 'Error' or 'SContinue'.
-    -- 2. Input stream position is reset to @current position + count@.
+    -- 1. If 'SPartial' result was returned in the past, @extract@ on @state@
+    -- would give that result otherwise it will return 'Error' or 'SContinue'.
+    -- 2. Input stream position is updated to @current position + count@.
     -- 3. the previous input is retained in a backtrack buffer.
 
     | SDone !Int !b
     -- ^ Done with leftover input count and result.
     --
-    -- @SDone count result@ means the parser has finished, it will accept no
-    -- more input, the final stream position must be set to @current position +
-    -- count@ and the result of the parser is in @result@.
+    -- @SDone count result@ means the parser has finished, it will not accept
+    -- any more input, the final stream position must be set to @current
+    -- position + count@ and the result of the parser is in @result@.
 
     | Error !String
     -- ^ Parser failed without generating any output.
@@ -466,7 +468,7 @@ data Parser a m b =
         (m (Initial s b))
         -- Extract can only return SPartial or SContinue n. In other words it
         -- can only backtrack or return partial result/error. But we do not
-        -- return result in Partial, therefore, we have to use SDone instead of
+        -- return result in SPartial, therefore, we have to use SDone instead of
         -- SPartial.
         (s -> m (Step s b))