Corrections to Water book

Page 7, example 1 (Ch. 1)

Action should be "/result", not "/results"

Revised example:

<FORM action="/result">
  First: <INPUT name="fname" value="Mike"/> <BR/>
  Last: <INPUT name="lname" value="Plusch"/>
  <INPUT type="submit" value="Go"/>
 </FORM>

Example in book (incorrect):

<FORM action="/results">
  First: <INPUT name="fname" value="Mike"/> <BR/>
  Last: <INPUT name="lname" value="Plusch"/>
  <INPUT type="submit" value="Go"/>
 </FORM>

Page 7, example 4 (Ch. 1)

Action can be the symbol result, although the string '/result' will also work. The 'to_html_attr' method converts an object into a URI string.

Revised example:

<defmethod registration fname="Mike"=string lname="Plusch"=string>
 <FORM action=result>
  First: <INPUT name="fname" value=fname/> <BR/>
  Last: <INPUT name="lname" value=lname/>
  <INPUT type="submit" value="Go"/>
 </FORM>
</defmethod>

Example in book (incorrect):

<defmethod registration fname="Mike"=string lname="Plusch"=string>
 <FORM action="/result">
  First: <INPUT name="fname" value=fname/> <BR/>
  Last: <INPUT name="lname" value=lname/>
  <INPUT type="submit" value="Go"/>
 </FORM>
</defmethod>

Page 8, example 5 (Ch. 1)

HTML should be BODY because in the XHTML standard, HTML does not permit any content except for the tags of BODY or HEAD. Although a valid XHTML file must start with an HTML tag, BODY works fine in most browsers.

Revised example:

<defmethod result fname lname>
 <BODY>
  <do fname/> <do lname/> has been registered.
 </BODY>
</defmethod>

Example in book (incorrect):

<defmethod result fname lname>
 <HTML>
  <do fname/> <do lname/> has been registered.
 </HTML>
</defmethod>

Page 9, example 1 (Ch. 1)

The URI needed a file extension (xml). When accessing an object through a URI, the format for the response is indicated though the file extension. If there is no file extension, then it assumes '.htm'. By default, a generic object does not have an HTML presentation defined on it, therefore the request returned an empty string.

Revised example:

<defclass point x y/>
<defmethod get_point>
 <vector>
  <point x=5 y=10/>
  <point x=3 y=3/>
 </vector>
</defmethod>
<web "http://localhost/get_point.xml?"/>.content

Example in book (incorrect):

<defclass point x y/>
<defmethod get_point>
 <vector>
  <point x=5 y=10/>
  <point x=3 y=3/>
 </vector>
</defmethod>
<web "http://localhost/get_point?"/>.content

Chapter 2

Page 19, example 2 (Ch. 2)

This is a better example to show how the tagname can be any expression including a local variable. "some_text" was changed to "editable". INPUT was changed to DIV.

Revised example:

<set editable=true/>
<set text_region=
  <if> editable
       hypertext.TEXTAREA
    else
       hypertext.DIV
  </if>
/>
<text_region>testing</>

Example in book (incorrect):

<set some_text="testing"/>
<set text_input=
  <if> some_text.<more 30/>  
    hypertext.TEXTAREA
  else                  
    hypertext.INPUT
  </if>
/>
<text_input 0=some_text/>

Page 20, example 2 (Ch. 2)

Definitions for 'list' and 'item' were added. This example shows a ConciseXML and XML 1.0 representation for the same object. The change makes it possible to execute the example without error.

Revised example:	<defclass list rest=true/> <defclass item name/> <list <item name="bread"/> <item name="milk"/> />
Example in book (incorrect):	<list <item name="bread"/> <item name="milk"/> />

Chapter 3

Page 25, example 1 (Ch. 3)

Added basic Water Contracts for purchase_order and line_item so that the example could execute.

Revised example:

<defclass purchase_order/> <defclass line_item/>
<purchase_order
  po_number="1001"
  line_items=<vector> 
              <line_item line=1 item="soap" quantity=2/>
              <line_item line=2 item="ice" quantity=3/>
             </>
/>

Page 26, example 3 (Ch. 3)

Added simple class (Water Contract) for employee so that the example could be executed.

Revised example:

<defclass employee/>
<set employee_bob=<employee name="Bob"/> /> 
employee_bob.<set manager=employee_bob/>.manager.name

Page 29, example 3 (Ch. 3)

_promote is not yet supported. See online documentation of 'rest' for the current supported solution.

Revised example:	<defclass grocery_list rest/> <grocery_list "apple" "milk" "pears" />
Example in book (incorrect):	<defclass grocery_list _promote='other_unkeyed_args'/> <grocery_list "apple" "milk" "pears" />

Page 30, example 1 (Ch. 3)

Simple class definitions were added so that the example can be executed.

Revised example:

<defclass grocery_item/>
<defclass grocery_list rest/>
<defclass gallon value/>

<grocery_list
  "apple"
  <grocery_item name="milk" quantity=<gallon 2/> />
  <grocery_item name="apple" quantity=2 />
/>

Chapter 4

Page 36, example 3 (Ch. 4)

Call to 'set' was not properly closed.

Revised example:

<set uppercase=type.<one_of <char "A"/> <char "B"/> <char "C"/> /> />
<thing last_name="AC"=type.<vector_of uppercase min=2 max=15/> />

Example in book (incorrect):

<set uppercase=type.<one_of <char "A"/> <char "B"/> <char "C"/> />
<thing last_name="AC"=type.<vector_of uppercase min=2 max=15/> /> />

Page 37, example 4 (Ch. 4)

Water 3 uses '_subject' in place of 'this'. The _subject is implied if you just use a single leading dot.

Revised example:

<defmethod carry_on_luggage> 
 _subject.girth.<less 40/>.<and _subject.weight.<less 25/> /> 
</defmethod>

type.<call_method_of carry_on_luggage/>.
  <is_type_for <thing girth=20 weight=10/> />

Example in book (incorrect):

<defmethod carry_on_luggage> 
 this.girth.<less 40/>.<and this.weight.<less 25/> /> 
</defmethod>

type.<call_method_of carry_on_luggage/>.
  <is_type_for <thing girth=20 weight=10/> />

Chapter 5

Page 45, example 1 (Ch. 5)

'other_unkeyed_args' is not yet supported. Use 'rest' instead.

Revised example:

<defclass grocery_list store_name=required 
                       rest />
<defclass grocery_item name=required quantity=1/>
<grocery_list 
  store_name="Acme Foods"
  "apple"
  <grocery_item name="milk"/>
  <grocery_item name="pears" quantity=3/>
/>

Example in book (incorrect):

<defclass grocery_list store_name=required 
                       items='other_unkeyed_args' />
<defclass grocery_item name=required quantity=1/>
<grocery_list 
  store_name="Acme Foods"
  "apple"
  <grocery_item name="milk"/>
  <grocery_item name="pears" quantity=3/>
/>

Page 46, example 3 (Ch. 5)

Changed 'defmethod' to 'defclass'. The use of 'other_keyed_args' is not yet supported.

Revised example:	<defclass foo other_named_args=true/> <foo yak="yum"/>.yak
Example in book (incorrect):	<defmethod foo misc=optional=other_keyed_args/> <foo yak="yum"/>.misc

Page 47, example 1 (Ch. 5)

Changed 'defmethod' to 'defclass'. The use of '_promote' and 'other_keyed_args' is not yet supported. See on-line documentation for the description of 'other_named_args'.

Revised example:	<defclass foo other_named_args=true/> <foo yak="yum"/>
Example in book (incorrect):	<defmethod foo _promote=optional=other_keyed_args/> <foo yak="yum"/>

Page 48, example 1 (Ch. 5)

'_precond' and '_postcond' are not yet supported.

Revised example:

<defmethod delete_my_database
  _precond=<defmethod> thing.<has_key my_database/> </>
  _postcond=<defmethod> thing.<has_key my_database/>.<not/> </>
/>

<defmethod increment_global_count_field
  _precond=<defmethod> 
             thing.<has_key "count"/>.<and args.count.<more 0/> />
           </defmethod>
  _postcond=<defmethod> 
             _args.count.<is count.<minus 1/> /> 
            </defmethod>
/>

<defmethod add_customer/>.
<doc
  precond="customer has never had an account"
  postcond="a single account exists for that customer"
/>

Chapter 6

Page 50, example 6 (Ch. 6)

Any reference to 'starting_object' should be 'a_starting_object'. This occurs in a number of examples in this chapter.

Revised example:	a_starting_object."0"
Example in book (incorrect):	starting_object."0"

Page 52, example 4 (Ch. 6)

'get_with_value' is not yet supported. There are several examples that use it in this chapter.

Revised example:

<set a_starting_object=
 <thing a_field=<thing foo="bar"/> 
        b_field=100 
        0=<vector "water" "ice"/>
        1=<thing x=5 y=10 foo="bar"/>
  /> 
/>
a_starting_object.<get_with_value "foo" "bar"/>

Page 54, example 3 (Ch. 6)

'starting_object' should be 'a_starting_object'. The 'include_value' argument is not yet supported. Use returns='all_except_null' and an 'if' statement to achieve the same result.

Revised example:

<set a_starting_object=
 <thing a_field=<thing foo="bar"/> 
        b_field=100 
        0=<vector "water" "ice"/>
        1=<thing x=5 y=10 foo="bar"/>
 /> 
/>
<defmethod foo_starts_with_ba>
 .<has_key "foo"/>.<and .foo.<starts_with "ba"/> />
</defmethod>

a_starting_object.
 <for_each returns='all_except_null'> 
  <if> value.<foo_starts_with_ba/>
       value
  </if>
 </for_each>

Example in book (incorrect):

<set a_starting_object=
 <thing a_field=<thing foo="bar"/> 
        b_field=100 
        0=<vector "water" "ice"/>
        1=<thing x=5 y=10 foo="bar"/>
 /> 
/>
<defmethod foo_starts_with_ba>
 .foo.<starts_with "ba"/>
</defmethod>
starting_object.<for_each include_value=foo_starts_with_ba returns='all'> value </for_each>

Page 55, example 3 (Ch. 6)

'starting_object' should be 'a_starting_object'. 'include_key' should be 'include'.

Revised example:

<set a_starting_object=
 <thing a_field=<thing foo="bar"/> 
        b_field=100 
        0=<vector "water" "ice"/>
        1=<thing x=5 y=10 foo="bar"/>
 /> 
/>
a_starting_object.<for_each include=vector_key returns='all'> value </for_each>

Example in book (incorrect):

<set a_starting_object=
 <thing a_field=<thing foo="bar"/> 
        b_field=100 
        0=<vector "water" "ice"/>
        1=<thing x=5 y=10 foo="bar"/>
 /> 
/>
starting_object.<for_each include_key=vector_key returns='all'> value </for_each>.<to_concise_xml/>

Chapter 43

Page 352, example 1 (Ch. 43)

Revised example:

<defclass faq 
  question="" 
  answer=""

  storage=filesystem.<file "C:/faqs.h2o"/>
>
<set N=_new_object/>  <!-- _new_object is faq here -->

N.<set edit=
 <active_value>
  <FORM action="/add">
   Question: <INPUT name="question" size=50/><BR/>
   Answer: <TEXTAREA name="answer" cols=50 rows=5/>
   <INPUT type="submit" value="Add FAQ"/>
   <P><A href="/">Show all FAQs</A></P>
   <do .<last/> />
  </FORM>
 </active_value>
/>

<defmethod ui_detail alert_msg=optional>
 <if> defclass.<is_type_for _subject/>
  <BODY>
   <H2>Frequently Asked Questions (FAQ's)</>
   <P>Total of <do .<length/> /> entries.</P>
   <do .<for_each include=vector_key returns='all'> value </> />
   <P><A href="/edit">Add FAQ</></>
   <P><A href="/save?">Save to disk</></>
   <do alert_msg/>
  </BODY>
  
  else
  <hypertext>
   <DIV><B>Q:</B> <do .question/> </DIV>
   <DIV><B>A:</B> <do .answer/> </DIV>
   <BR/>
  </hypertext>
 </if>
</defmethod>
 
<defmethod add question answer>
 <faq question answer/>
 .edit
</defmethod>
 
<defmethod save>
 <set the_faqs=""/>
 .<for_each include=vector_key>
   <set the_faqs=the_faqs.<concat value.<to_concise_xml/> /> />
 </for_each>
 .storage.<set content=the_faqs/>
 .<ui_detail 
   alert_msg=<P><do .<length/> /> records saved in <do .storage/>
                on <do datetime.current/> 
             </P>
 />
</defmethod>
 
<defmethod init>
 <set N=_new_object/>
 N._parent.<insert N/>
 N
</defmethod>
 
<defmethod to_html>
 .<ui_detail/>.<to_html/>
</defmethod>
 
<if> N.storage.<exists/>
     N.storage.<execute/>
  else
    <do>
     <faq "What's MPH?" "Miles per Hour" />
     <faq "What's KPH?" "Kilometers per Hour" />
    </do>
</if>
 
</defclass>

<server faq/>

<open_browser_window "http://localhost"/>

Water: Simplified Web Services and XML Programming

Corrections by Chapter

Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 6

Chapter 43