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_______________________________________________________________________
Chapter 2: PADtalk Scripts 13
________________________________________________________________________
CHAPTER TWO: PADTALK SCRIPTS
CONSTRUCTING SCRIPTS
In HyperPAD, scripts are written using the Script Editor. In order to
access an object's script, the pad's user level must be set to
scripting. (See the section on user levels in the HyperPAD User's Guide
for additional information.)
To access an object's script:
1. Make sure the pad's user level is set to Scripting.
2. Select the object with the Selector tool.
In order to access a button or field's script, you must use the Selector
tool and select the object.
3. Open the object's Info dialog box from the Objects menu.
Depending on the type of object you are working with, select Pad, Bkgnd,
Page, Button, or Field Info from the Objects menu.
4. Select the <Script...> button from the dialog box.
The Script Editor will be loaded along with the object's script.
_______________________________________________________________________
Chapter 2: PADtalk Scripts 14
________________________________________________________________________
THE SCRIPT EDITOR
The Script Editor is an environment that allows you to edit an object's
script and then compile it. It looks like this:
┌───────────────────────────────────────────────────────────────────────┐
│ │
│ **** The Printed Documentation has a picture or screen shot here **** │
│ │
└───────────────────────────────────────────────────────────────────────┘
EXITING THE SCRIPT EDITOR:
To exit the Script Editor and return to the previous screen, use one of
the following methods:
1. Press ESC. If you have made any modifications, you will be asked if
you want to save them.
2. Select Cancel from the File menu. Any changes you made will be lost.
3. Select Save and Return from the File menu. This saves any changes
and then returns to the pad.
LET'S START SCRIPTING:
Let's create a very simple script linking a newly created button to the
Home pad. (If you are going to do the procedures, you should create a
new pad and a new button.)
To create a new pad:
1. Set the user level to scripting. (See the section on user levels in
the HyperPAD User's Guide.)
_______________________________________________________________________
Chapter 2: PADtalk Scripts 15
________________________________________________________________________
2. Select the New command from the File menu.
3. Type in the name of your pad and press ENTER.
A blank page will be placed on-screen.
To create a new button:
1. Set the user level to scripting.
2. Select the Select tool from the Tools menu.
3. Select the New Button command from the Objects menu.
A new button will appear on-screen.
To go to the button's script:
1. Select Button Info from the Objects menu (or just press ENTER).
2. Select the button (or press ALT+S).
First, access the button's script. When the Script Editor loads, you'll
see that HyperPAD has already written part of the script for you.
Because almost all buttons created in HyperPAD respond to being
selected, each button's script, by default, provides an empty select
handler.
┌───────────────────────────────────────────────────────────────────────┐
│ │
│ **** The Printed Documentation has a picture or screen shot here **** │
│ │
└───────────────────────────────────────────────────────────────────────┘
First, examine the script HyperPAD has provided, line by line:
handler select;
A handler is a portion of an object's script that defines what happens
when a certain message is received. Each handler statement, like the one
_______________________________________________________________________
Chapter 2: PADtalk Scripts 16
________________________________________________________________________
above, names the message the handler responds to (in this case the
select message) and must end with a semi-colon. The name determines
which message triggers the execution of this handler.
For more information on messages see Chapter Ten.
begin
end;
The begin and end statements enclose the list of actions that make up
this handler. When the select message is received by this button, the
action statements listed between the begin and end statements will be
executed.
handler select;
begin
[statements executed when the button is selected]
end;
Each begin statement must have a corresponding end statement in order
for the handler to be valid. A semi-colon must follow the end statement,
signifying the end of the handler.
The blank line that HyperPAD has left is for the author to complete. In
between the begin and end statements, fill in the actions to be taken
when this button is selected. In this case, we want the user to change
to the next page. To complete the handler, add the following line:
go to the next page;
HyperPAD does not distinguish between upper and lower case letters - it
recognizes go to the next page; and Go To The Next Page; as the same
statement.
Every PADtalk statement within a begin...end block must end with a semi-
colon. You can incorporate numerous commands to execute by inserting
them between the begin and end statements. The full handler should
resemble the following:
handler select;
begin
go to the next page;
end;
We have just created a script with one handler that responds to the
select message. If the user selects this button (by pressing ENTER or
with the mouse) the handler will execute, changing to the next page in
the pad.
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Chapter 2: PADtalk Scripts 17
________________________________________________________________________
Scripts can contain many handlers allowing objects to respond to a
variety of messages. For example, the following script responds to three
messages:
handler select;
begin
go to the next page;
end;
handler mouseUp;
begin
beep;
end;
handler mouseEnter;
begin
hide the menu bar;
end;
WRITING STATEMENTS IN PADTALK
Each PADtalk statement ends with a semi-colon. A begin...end block, like
in the Pascal languages, is really a single compound statement (that's
why there is a semi-colon after the end).
PADtalk is a flexible language. It sometimes provides more than one way
to perform the same action. For example, the following statements access
the next page:
go to the next page;
go to next page;
go next page;
go to page (currentPage() + 1);
In many PADtalk statements, like the go statement shown above, you can
use the word the. The use of this word is optional and has no purpose
except to enhance readability of your scripts. (The exception is with
the alternate syntax of function calls.)
You can add comments to your scripts by enclosing them in curly
brackets. Any text within brackets is ignored by the compiler. The
following example shows a comment enclosed in brackets.
{ this is a comment }
go to the next page;
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Chapter 2: PADtalk Scripts 18
________________________________________________________________________
Brackets can enclose many lines, shown in the following example:
{ this is a comment that
takes up two lines }
go to the next page;
You can also enclose comments within other comments. The following
example comments out a few statements that have comments:
{
go to the next page; { change pages }
beep; { emit a sound }
answer "Find What?"; { ask user question }
}
You can add a comment to the end of a line by using two consecutive
hyphens (--). The text between the two hyphens and the end of the line
is ignored by the compiler. For example:
-- this is a comment
go to the next page; -- this is a comment too!
PADtalk is a verbose language that understands over 400 different words.
Before exploring it, become comfortable within the Script Editor.
USING THE KEYBOARD
Press this key: To:
------------------------------------------------------------------------
UP and DOWN Move up or down one line in a script
LEFT and RIGHT To move left or right on a line in a script
HOME Go to the beginning of a line
CTRL+HOME Go to the beginning of the script
END Go to the end of the line
CTRL+END Go to the end of the script
CTRL+RIGHT or CTRL+LEFT Move forward or backward one word
BACKSPACE Delete the previous character
DEL Delete the character under the cursor
CTRL+Y or CTRL+D Delete the current line
CTRL+BACKSPACE Delete the previous word
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Chapter 2: PADtalk Scripts 19
________________________________________________________________________
Press this key: To:
---------------------------------------------------------
SHIFT+ARROWS Select text
ESC or CTRL+Q Exit with a check to save changes
CTRL+C or CTRL+INS Copy selected text
TAB Inserts space up to next tab stop
PGUP or MINUS (keypad) Move up one page
PGDN or PLUS (keypad) Move down one page
CTRL+X or SHIFT+DEL Cut text
CTRL+V or SHIFT+INS Paste text
CTRL+DEL Delete to the end of the line
CTRL+F Find a string
CTRL+R Find and replace text
CTRL+N Find next occurrence of the string
F4 Compile the script, checking for errors
F10 Open the menus
EDITING A SCRIPT
In the Script Editor, you can copy and move blocks of text within a
script or even between scripts.
Before you can using any of the editing features, you have to select the
text you want to perform the operation on.
To select text:
1. Place the cursor on the first character of the selection.
2. Hold down SHIFT and use the arrow keys to extend the selection.
3. When you've highlighted the entire selection, release the keys.
To use the mouse, place the mouse pointer where you want to begin your
selection. Hold down the left mouse button and drag the mouse until
you've highlighted the selection. Then, release the mouse button. Once
the text is selected, you can copy, cut, or delete it.
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Chapter 2: PADtalk Scripts 20
________________________________________________________________________
To copy text:
1. Select the text.
2. Select the Copy command from the Edit menu (ALT+E, C).
To cut text:
1. Select the text.
2. Select the Cut command from the Edit menu (ALT+E, T).
To paste text:
1. Position the cursor where you want to place the text.
2. Select the Paste command from the Edit menu (ALT+E, P).
The contents of the clipboard will be inserted in the script.
SEARCH AND REPLACE
As you become more comfortable with PADtalk, your scripts will become
longer and more complex. To reduce the amount of time and effort
necessary to locate text, HyperPAD includes Search and Replace commands.
To locate a string in a script:
1. Select the Find command from the Search menu (ALT+S, F).
The Find dialog box will appear on screen.
2. Type in the string you want to locate and press ENTER.
To locate the next instance of a string:
1. First complete the above procedure.
2. Select the Find Next command from the Search menu (ALT+S, N).
To keep looking for that string, continue to select the Find Next
command. CTRL+N is the shortcut for this command.
Sometimes, you may need to replace a string in a script with another.
Use the Replace command to locate the instance and replace it with what
you've specified.
_______________________________________________________________________
Chapter 2: PADtalk Scripts 21
________________________________________________________________________
To search and replace within a script:
1. Select the Replace command from the Search menu.
2. Enter in the search and replace text, then select:
Verify - Allows you to confirm each replacement.
Replace - Replace the text and continue.
Skip - Continue without replacing the text.
Cancel - Stop the procedure.
PRINTING SCRIPTS
To print the scripts in your pads:
1. Select Printer Setup from the File menu and complete the dialog box
so the options conform to your system. If your printer is not listed,
select the Generic Printer, or another that your printer can emulate.
2. Select Page Setup from the File menu and make sure the settings are
correct.
3. Select the Print command from the File menu.
COMPILING SCRIPTS
Before HyperPAD can use your scripts, they must first be compiled.
HyperPAD compiles and saves your script when you exit the Script Editor.
As it compiles, HyperPAD scans the script, checking for syntax errors.
HyperPAD is only able to pass messages to handlers in scripts that have
been successfully compiled without any errors.
You can manually check for errors before exiting the Script Editor by
selecting Compile from the Edit menu (or press F4). If there is an
error, HyperPAD will assist you by positioning the cursor at the
location of the error and displaying an error message.
COMPILING WITH THE DEBUGGING SWITCH
Runtime errors occur when something goes wrong in a script while
browsing your pad. Normally, HyperPAD will take you to the offending
script so that you can correct the problem. With larger scripts that
contain many handlers, it may be difficult to locate the source of a
runtime error.
_______________________________________________________________________
Chapter 2: PADtalk Scripts 22
________________________________________________________________________
To assist you in locating runtime errors, you can turn on the Debug
option on the Edit menu. When you compile the script with the Debug
option on, HyperPAD includes line number information with the compiled
code. Then, following a runtime error, HyperPAD places the cursor
directly on the line in which the error occurred. If you compile with
the Debug option off and a runtime error occurs, HyperPAD simply places
the cursor at the top of the offending script.
THE COMPONENTS OF A SCRIPT
A script consists of handlers, which you were introduced to above, and
functions, which will be introduced in this section.
HANDLERS
As you have learned, a handler is a portion of a script that is invoked
when a specific message is received by the object that contains it. Each
handler names the message it responds to and includes some action(s) to
be taken when that message is received.
Here is a more complex handler. It receives two parameters from the
statement that calls it.
handler calcResult(i,j);
begin
put i * j / 100 into the message box;
end;
Sometimes, you may want a handler to receive a variable number of
parameters. In this case, it is necessary to know how many parameters
were passed to your handler and what each of them are. This is
accomplished using the functions param, paramCount, and params. These
functions return information about the number of parameters that were
passed to your handler, the entire parameter list, and what each
parameter is. The following function sums its parameters and returns the
total to the calling statement.
function addNums;
begin
put 0 into total;
for i = 1 to the paramCount do
add param(i) to total;
return total;
end;
Notice that this example doesn't declare any parameter variables.
Instead, it accesses the parameters using the param function.
_______________________________________________________________________
Chapter 2: PADtalk Scripts 23
________________________________________________________________________
DEFINING YOUR OWN FUNCTIONS
In addition to handlers, scripts can contain your own functions. A
function is a group of statements that returns a single value. Functions
can be called from other handlers in the same script, or from scripts
higher in the message hierarchy.
For example, the following function asks a question in a dialog box
using the answer command, then returns the result to the caller using
the return statement.
function okToContinue;
begin
answer "Is it safe";
return it;
end;
The return statement defines the number or text value that the function
will return to the calling statement. The return statement will not stop
execution of the handler (only exit and pass stop the execution of a
handler). If you specify more than one return statement, the last return
statement executed will determine the returned value of the function.
Calling your own functions is just like calling HyperPAD's built-in
functions. The following statements call the function defined above:
put okToContinue() into res;
if okToContinue() is "Cancel" then beep;
put "You selected" & okToContinue();
The open and close parenthesis are used to distinguish a function call
from a message name. The statement
okToContinue;
is a message name that gets sent to the current script, where as
okToContinue()
calls the user-defined function.
_______________________________________________________________________
Chapter 2: PADtalk Scripts 24
________________________________________________________________________
The following example function counts the number of Bs in a passed
parameter.
function countBs(str);
begin
put 0 into total;
for i = 1 to the length(str) do
if char i of str is "B" then add 1 to total;
return total;
end;
To call this function:
put 5 + countBs("Bobby and Billy when out.");
OTHER DEFINITIONS
The following definitions are intended to introduce you to other PADtalk
components used when writing scripts.
COMMANDS
Commands are statements that tell HyperPAD what to do. Each command ends
with a semi-colon. For example:
go to page 1;
put "wow" into page field 1;
HyperPAD's built-in commands are discussed in Chapter Eleven.
CONSTANTS
A constant is any named value that can't be changed. Unlike a variable,
you can not alter a constant, and unlike a literal, its value is not
always identical to its name. The following tables summarize HyperPAD's
constants and their corresponding values.
_______________________________________________________________________
Chapter 2: PADtalk Scripts 25
________________________________________________________________________
MISCELLANEOUS CONSTANTS
The miscellaneous constants are:
Constant: Description:
----------------------------------------------------
empty Empty String ""
false Boolean value false
true Boolean value true
pi The mathematical constant 3.14159
up Returned by ctrlKey(), altKey(), and shiftKey()
down Returned by ctrlKey(), altKey(), and shiftKey()
CHARACTER CONSTANTS
The character constants are:
Constant: Description:
----------------------------------------------------
formfeed ASCII 12
linefeed ASCII 10
quote ASCII 34(")
return ASCII 13
space ASCII 32(" ")
tab ASCII 9
_______________________________________________________________________
Chapter 2: PADtalk Scripts 26
________________________________________________________________________
PROPERTY CONSTANTS
The property constants are:
Constant: Used with this property:
----------------------------------------------------
centered align
checkBox style
even parity
fat cursor
layer tabbing
left namePosition, align
listBox style
none parity
odd parity
off cursor, printer, mouse
on mouse, printer
opaque style
position tabbing
right align
scrolling style
thin cursor
top nameposition
transparent style
NUMERIC CONSTANTS
The following constants can be used in place of any number to enhance
readability of your scripts. The numeric constants are:
zero three six nine
one four seven ten
two five eight
_______________________________________________________________________
Chapter 2: PADtalk Scripts 27
________________________________________________________________________
LITERALS
A literal is a number or text string enclosed in quotes. The following
are literals:
10
17.39
"hello"
Special codes can be inserted into quoted text strings for characters
that you can't easily type with the keyboard. Each code is started with
the caret (^). The following table shows the supported codes and lists
some examples:
Code: Value:
----------------------------------------------------
^^ ^
^" "
^f formfee (ASCII 12)
^n linefeed (ASCII 10)
^t tab (ASCII 9)
^r carriage return (ASCII 13)
^d<n> ASCII character n (where n is the 3 digit character number)
^x<n> ASCII character n (where n is the hex character number)
Examples:
"The quick brown ^"fox^" jumped over the lazy dog"
"^rThis is a new line"
"square character ^d254 inserted here"
"hex ^xf4 insert here"
_______________________________________________________________________
Chapter 2: PADtalk Scripts 28
________________________________________________________________________
FUNCTIONS
HyperPAD contains many built-in functions, each of which return a single
value. Some functions require you to pass some parameters. The following
are a few of HyperPAD's built-in functions:
min(10,12)
time()
files("*.DOC")
HyperPAD's functions are discussed in Chapter Thirteen.
PROPERTIES
Properties are values that control how objects look and behave. All
objects of the same type have the same properties, but each object has
its own values for these properties. Color, for example, is a property
of buttons. All buttons have the color property and all buttons may be a
different color. The following are properties:
lockText
insertPoint
hilite
Object properties are discussed in Chapter Twelve.
CONTAINERS
A container is a storage place for a value. The following are
containers:
fields
variables
the message box
selectedText
Containers are discussed in Chapter Four.
