- removed enumeration size spec. so its now in programmer's

reference
* correct integer -> Integer

docs/ref.tex

@@ -557,7 +557,7 @@ Type & Range & Size in bytes \\ \hline
 Byte & 0 .. 255 & 1 \\
 Shortint & -128 .. 127 & 1\\
 Smallint & -32768 .. 32767 & 2\\
-integer & either smallint, longint or int64  & size 2,4 or 8 \\
+Integer & either smallint, longint or int64  & size 2,4 or 8 \\
 Word & 0 .. 65535 & 2 \\
 Longint & -2147483648 .. 2147483647 & 4\\
 Cardinal & 0..4294967295 & 4 \\
@@ -666,13 +666,16 @@ in mind:
 \item The \var{Pred} and \var{Succ} functions cannot be used on
 this kind of enumeration types. Trying to do this anyhow will result in a 
 compiler error.
-\item Enumeration types are by default stored in 4 bytes. This behaviour can be changed
+\item Enumeration types are by default stored using the same default size. This behaviour can be changed
 with the \var{\{\$PACKENUM n\}} compiler directive, which
 tells the compiler the minimal number of bytes to be used for enumeration
-types.
+types. More information can be found in the \progref, in the compiler directives
+and memory issues sections.
+
 For instance
 \begin{verbatim}
 Type
+{$PACKENUM 4}
   LargeEnum = ( BigOne, BigTwo, BigThree );
 {$PACKENUM 1}
   SmallEnum = ( one, two, three );
@@ -689,8 +692,7 @@ Small enum : 1
 Large enum : 4
 \end{verbatim}
 \end{enumerate}
-More information can be found in the \progref, in the compiler directives
-section.
+
 \subsubsection{Subrange types}
 A subrange type is a range of values from an ordinal type (the {\em host}
 type). To define a subrange type, one must specify it's limiting values: the
@@ -750,9 +752,8 @@ When the single quote character must be represented, it should be typed
 two times successively, thus \var{''''} represents the single quote character.
 
 \subsection{Strings}
-\fpc supports the \var{String} type as it is defined in Turbo Pascal
-(A sequence of characters with a specified length) and it
-supports ansistrings as in Delphi.
+\fpc supports the \var{String} type as it is defined in Turbo Pascal and
+it supports ansistrings as in Delphi.
 To declare a variable as a string, use the following type specification:
 \input{syntax/sstring.syn}
 
@@ -762,7 +763,7 @@ ansistrng or a short string.
 
 Whatever the actual type, ansistrings and short strings can be used
 interchangeably. The compiler always takes care of the necessary type
-conversions. Note, however, that the result of an expression that contains
+coversions. Note, however, that the result of an expression that contains
 ansistrings and short strings will always be an ansistring.
 
 \subsection{Short strings}
@@ -781,9 +782,11 @@ The predefined type \var{ShortString} is defined as a string of length 255:
  ShortString = String[255];
 \end{verbatim}
 
+For short strings \fpc reserves \var{Size+1} bytes for the string \var{S},
+and in the zeroeth element of the string (\var{S[0]}) it will store the
+length of the variable.
 If the size of the string is not specified, \var{255} is taken as a
-default. The length of the string can be obtained with the \seef{Length}
-standard runtime routine.
+default.
 For example in
 \begin{verbatim}
 {$H-}
@@ -792,8 +795,9 @@ Type
    NameString = String[10];
    StreetString = String;
 \end{verbatim}
-\var{NameString} can contain a maximum of 10 characters. While
-\var{StreetString} can contain up to 255 characters.
+\var{NameString} can contain maximum 10 characters. While
+\var{StreetString} can contain 255 characters. The sizes of these variables
+are, respectively, 11 and 256 bytes.
 
 \subsection{Ansistrings}
 
@@ -805,12 +809,23 @@ counted. Internally, an ansistring is treated as a pointer.
 
 If the string is empty (\var{''}), then the pointer is nil.
 If the string is not empty, then the pointer points to a structure in
-heap memory.
+heap memory that looks as in \seet{ansistrings}.
+
+\begin{FPCltable}{rl}{AnsiString memory structure}{ansistrings}
+Offset & Contains \\ \hline
+-12  & Longint with maximum string size. \\
+-8   & Longint with actual string size.\\
+-4   & Longint with reference count.\\
+0    & Actual string, null-terminated. \\ \hline
+\end{FPCltable}
+
+Because of this structure, it is possible to typecast an ansistring to a
+pchar. If the string is empty (so the pointer is nil) then the compiler
+makes sure that the typecasted pchar will point to a null byte.
 
-It is possible to typecast an ansistring to a pchar.
-If the string is empty (so the pointer is nil) then the compiler
-makes sure that the typecasted pchar will point to a null byte. AnsiStrings
-can be unlimited in length.
+AnsiStrings can be unlimited in length. Since the length is stored,
+the length of an ansistring is available immediatly, providing for fast
+access.
 
 Assigning one ansistring to another doesn't involve moving the actual
 string. A statement
@@ -853,8 +868,14 @@ statements:
 then a copy of the string is created before the assignment. This is known
 as {\em copy-on-write} semantics.
 
-The \seef{Length} function must be used to get the length of an
-ansistring.
+It is impossible to access the length of an ansistring by referring to
+the zeroeth character. The following statement will generate a compiler
+error if S is an ansistring:
+\begin{verbatim}
+  Len:=S[0];
+\end{verbatim}
+Instead, the \seef{Length} function must be used to get the length of a
+string.
 
 To set the length of an ansistring, the \seep{SetLength} function must be used.
 Constant ansistrings have a reference count of -1 and are treated specially.