From 9fe8adf35c16ab5d4566b03f3b36863c90b5b6dd Mon Sep 17 00:00:00 2001 From: Hans Bolinder Date: Thu, 12 Mar 2015 15:35:13 +0100 Subject: Update Erlang Reference Manual Language cleaned up by the technical writers xsipewe and tmanevik from Combitech. Proofreading and corrections by Hans Bolinder. --- system/doc/reference_manual/data_types.xml | 164 ++++++++++++++++------------- 1 file changed, 93 insertions(+), 71 deletions(-) (limited to 'system/doc/reference_manual/data_types.xml') diff --git a/system/doc/reference_manual/data_types.xml b/system/doc/reference_manual/data_types.xml index 37c0db5ff7..6226fa2f31 100644 --- a/system/doc/reference_manual/data_types.xml +++ b/system/doc/reference_manual/data_types.xml @@ -4,7 +4,7 @@
- 20032013 + 20032015 Ericsson AB. All Rights Reserved. @@ -28,12 +28,12 @@ data_types.xml
+

Erlang provides a number of data types, which are listed in + this section.

Terms -

Erlang provides a number of data types which are listed in this - chapter. A piece of data of any data type is called a - term.

+

A piece of data of any data type is called a term.

@@ -44,16 +44,17 @@ $char

- ASCII value of the character char. + ASCII value or unicode code-point of the character + char. base#value

- Integer with the base base, which must be an + Integer with the base base, that must be an integer in the range 2..36.

In Erlang 5.2/OTP R9B and earlier versions, the allowed range is 2..16. -

Examples:

+

Examples:

 1> 42.
 42
@@ -75,11 +76,11 @@
 
   

     Atom
-    
An atom is a literal, a constant with name. An atom should be
+    
An atom is a literal, a constant with name. An atom is to be
       enclosed in single quotes (') if it does not begin with a
       lower-case letter or if it contains other characters than
       alphanumeric characters, underscore (_), or @.

-    
Examples:

+    
Examples:

     
 hello
 phone_number
@@ -90,11 +91,11 @@ phone_number
   

     Bit Strings and Binaries
     
A bit string is used to store an area of untyped memory.

-    
Bit Strings are expressed using the
+    
Bit strings are expressed using the
       bit syntax.

-    
Bit Strings which consists of a number of bits which is evenly 
-      divisible by eight are called Binaries

-    
Examples:

+    
Bit strings that consist of a number of bits that are evenly
+      divisible by eight, are called binaries

+    
Examples:

     
 1> <<10,20>>.
 <<10,20>>
@@ -102,12 +103,14 @@ phone_number
 <<"ABC">>
 1> <<1:1,0:1>>.
 <<2:2>>

-    
More examples can be found in Programming Examples.

+    
For more examples,
+      see 
+      Programming Examples.

   

 
   

     Reference
-    
A reference is a term which is unique in an Erlang runtime
+    
A reference is a term that is unique in an Erlang runtime
       system, created by calling make_ref/0.

   

 
@@ -116,34 +119,42 @@ phone_number
     
A fun is a functional object. Funs make it possible to create
       an anonymous function and pass the function itself -- not its
       name -- as argument to other functions.

-    
Example:

+    
Example:

     
 1> Fun1 = fun (X) -> X+1 end.
 #Fun<erl_eval.6.39074546>
 2> Fun1(2).
 3

-    
Read more about funs in Fun Expressions. More examples can be found in Programming
-      Examples.

+    
Read more about funs in 
+      Fun Expressions. For more examples, see
+      
+      Programming Examples.

   

 
   

     Port Identifier
-    
A port identifier identifies an Erlang port. open_port/2,
-      which is used to create ports, will return a value of this type.

+    
A port identifier identifies an Erlang port.

+    
open_port/2, which is used to create ports, returns
+      a value of this data type.

     
Read more about ports in Ports and Port Drivers.

   

 
   

     Pid
-    
A process identifier, pid, identifies a process.
-      spawn/1,2,3,4, spawn_link/1,2,3,4 and
-      spawn_opt/4, which are used to create processes, return
-      values of this type. Example:

+    
A process identifier, pid, identifies a process.

+    
The following BIFs, which are used to create processes, return
+      values of this data type:

+    
+      spawn/1,2,3,4
+      spawn_link/1,2,3,4
+      spawn_opt/4
+    
+    
Example:

     
 1> spawn(m, f, []).
 <0.51.0>

-    
The BIF self() returns the pid of the calling process.
-      Example:

+    
In the following example, the BIF self() returns
+      the pid of the calling process:

     
 -module(m).
 -export([loop/0]).
@@ -166,14 +177,14 @@ who_are_you

 
   

     Tuple
-    
Compound data type with a fixed number of terms:

+    
A tuple is a compound data type with a fixed number of terms:

     
 {Term1,...,TermN}

     
Each term Term in the tuple is called an
       element. The number of elements is said to be
       the size of the tuple.

     
There exists a number of BIFs to manipulate tuples.

-    
Examples:

+    
Examples:

     
 1> P = {adam,24,{july,29}}.
 {adam,24,{july,29}}
@@ -191,7 +202,8 @@ adam
 
   

     Map
-    
Compound data type with a variable number of key-value associations:

+    
A map is a compound data type with a variable number of
+      key-value associations:

     
 #{Key1=>Value1,...,KeyN=>ValueN}

 	
Each key-value association in the map is called an
@@ -199,7 +211,7 @@ adam
 		called elements. The number of association pairs is said to be
       the size of the map.

     
There exists a number of BIFs to manipulate maps.

-    
Examples:

+    
Examples:

     
 1> M1 = #{name=>adam,age=>24,date=>{july,29}}.
 #{age => 24,date => {july,29},name => adam}
@@ -214,16 +226,18 @@ adam
 6> map_size(#{}).
 0

     
A collection of maps processing functions can be found in
-	the STDLIB module maps.

-    
Read more about Maps.

+      maps manual page
+      in STDLIB.

+    
Read more about maps in 
+      Map Expressions.

   
-	  
Maps are considered experimental during OTP 17.

+    
Maps are considered to be experimental during Erlang/OTP R17.

   
   

 
   

     List
-    
Compound data type with a variable number of terms.

+    
A list is a compound data type with a variable number of terms.

     
 [Term1,...,TermN]

     
Each term Term in the list is called an
@@ -231,20 +245,21 @@ adam
       the length of the list.

     
Formally, a list is either the empty list [] or
       consists of a head (first element) and a tail
-      (remainder of the list) which is also a list. The latter can
+      (remainder of the list).
+      The tail is also a list. The latter can
       be expressed as [H|T]. The notation
-      [Term1,...,TermN] above is actually shorthand for
+      [Term1,...,TermN] above is equivalent with
       the list [Term1|[...|[TermN|[]]]].

-    
Example:      


-[] is a list, thus      


+    
Example:

+
[] is a list, thus      


 [c|[]] is a list, thus      


 [b|[c|[]]] is a list, thus      


-[a|[b|[c|[]]]] is a list, or in short [a,b,c].

-    

+[a|[b|[c|[]]]] is a list, or in short [a,b,c]

+
     
A list where the tail is a list is sometimes called a proper list. It is allowed to have a list where the tail is not a
-      list, for example [a|b]. However, this type of list is of
+      list, for example, [a|b]. However, this type of list is of
       little practical use.

-    
Examples:

+    
Examples:

     
 1> L1 = [a,2,{c,4}].
 [a,2,{c,4}]
@@ -261,18 +276,19 @@ a
 7> length([]).
 0

     
A collection of list processing functions can be found in
-      the STDLIB module lists.

+      the lists manual
+      page in STDLIB.

   

 
   

     String
     
Strings are enclosed in double quotes ("), but is not a
-      data type in Erlang. Instead a string "hello" is
-      shorthand for the list [$h,$e,$l,$l,$o], that is
+      data type in Erlang. Instead, a string "hello" is
+      shorthand for the list [$h,$e,$l,$l,$o], that is,
       [104,101,108,108,111].

     
Two adjacent string literals are concatenated into one. This is
-      done at compile-time and does not incur any runtime overhead.
-      Example:

+      done in the compilation, thus, does not incur any runtime overhead.

+      
Example:

     
 "string" "42"

     
is equivalent to

@@ -284,12 +300,13 @@ a
     Record
     
A record is a data structure for storing a fixed number of
       elements. It has named fields and is similar to a struct in C.
-      However, record is not a true data type. Instead record
+      However, a record is not a true data type. Instead, record
       expressions are translated to tuple expressions during
       compilation. Therefore, record expressions are not understood by
-      the shell unless special actions are taken. See shell(3)
-      for details.

-    
Examples:

+      the shell unless special actions are taken. For details, see the
+      shell(3) manual
+      page in STDLIB).

+    
Examples:

     
 -module(person).
 -export([new/2]).
@@ -303,14 +320,15 @@ new(Name, Age) ->
 {person,ernie,44}

     
Read more about records in
       Records. More examples can be
-      found in Programming Examples.

+      found in 
+      Programming Examples.

   

 
   

     Boolean
     
There is no Boolean data type in Erlang. Instead the atoms
       true and false are used to denote Boolean values.

-    
Examples:

+    
Examples:

     
 1> 2 =< 3.
 true
@@ -329,76 +347,80 @@ true

       
       
         \b
-        backspace
+        Backspace
       
       
         \d
-        delete
+        Delete
       
       
         \e
-        escape
+        Escape
       
       
         \f
-        form feed
+        Form feed
       
       
         \n
-        newline
+        Newline
       
       
         \r
-        carriage return
+        Carriage return
       
       
         \s
-        space
+        Space
       
       
         \t
-        tab
+        Tab
       
       
         \v
-        vertical tab
+        Vertical tab
       
       
         \XYZ, \YZ, \Z
-        character with octal representation XYZ, YZ or Z
+        Character with octal
+        representation XYZ, YZ or Z
       
       
         \xXY
-        character with hexadecimal representation XY
+        Character with hexadecimal
+        representation XY
       
       
         \x{X...}
-        character with hexadecimal representation; X... is one or more hexadecimal characters
+        Character with hexadecimal
+        representation; X... is one or more hexadecimal characters
       
       
         \^a...\^z        


 \^A...\^Z
-        control A to control Z
+        Control A to control Z
       
       
         \'
-        single quote
+        Single quote
       
       
         \"
-        double quote
+        Double quote
       
       
         \\
-        backslash
+        Backslash
       
-      Recognized Escape Sequences.
+      Recognized Escape Sequences
     
   

 
   

     Type Conversions
-    
There are a number of BIFs for type conversions. Examples:

+    
There are a number of BIFs for type conversions.

+    
Examples:

     
 1> atom_to_list(hello).
 "hello"
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