Objective - Students will become familiar with basic computer programming terminology (HyperTalk, Scripting, Syntax).
BASIC
Computer Programming used to be very difficult. Most computer programs used to look like random numbers and letters to the untrained eye.
Then came a programming language called “BASIC”. BASIC was the first computer programming language that read like english. Look at the following BASIC program:
10 put 4 into a
20 if a = 4 then go to line 40
30 go to line 10
40 end
BASIC changed the way people programmed. But it was not powerful enough to do many things, and it too k hundreds of lines of code to make a worthwhile program.
HyperTalk
HyperCard, a program for that Mac that allows people to make their own computer programs, uses a computer programming language called HyperTalk. HyperTalk is very powerful, yet it is oneof the easiest programming language to learn. HyperTalk is the language we will be learning.
Scripts and Scripting
In HyperTalk, a script refers to a small program written in HyperTalk. Just like an actress follows a script on stage, the computer will follow your script! A script, which is a computer program, is a set of directions for the computer to follow. If you give someone bad directions, they will get lost. If you give a computer bad directions, it not do what you want it to. In some cases, it will tell you that your directions are bad.
Syntax
Syntax is to HyperTalk what grammar is to the english language. Syntax is the exact wording of scripts. In HyperTalk, one wrong letter can totally change the function of a script, making it do somet •hing weird, or not do anything at all!
Question - Why did BASIC change the way people programmed?
Question - What is a “Script”?
Question - What will happen if you write a script with an error in it? Question - What is “Syntax?”
Lesson Two - The “Add” Command
Objective - Students will define a “card field”, understand how the “add” command works, and write scripts utilizing the “add” command.
Read the following script:
on mouseUp
put 8 + 2 into card field “a”
end mouseUp
Type the above script into Student Programmer, and then run it. Student Programmer will put the number 10 into card field “a”. Card fields are areas on the screen where text can £be entered. The first line of the script, “on mouseUp”, and the last line of the script, “end mouseUp”, are together called a “handler”. They tell the computer to run the script when the user lets up on the mouse button.
Question - What is a card field?
Question - How did the program know to put 10 into card field “a”?
Question - Why did the program put 10 into card field “a” instead of “8 + 2”?
Question - Why do you suppose the last line of this script is “end mouseUp”?
Extra Practice - Write your own script that adds two numbers together.
Extra Challenge - Write your own script that adds to numbers, and puts the answer in all 5 card fields (a through e)!
Lesson Three - The “Add” Command
Objective - Students will write scripts utilizing the “add” command.
1. Read the following script:
on mouseUp
put 10 into card field “a”
put 9 into card field “b”
put card field “a” + card field “b” into car ˇd field “c”
end mouseUp
Type the above script into Student Programmer and run it. Student Programmer will put 10 into field “a”, 9 into field “b”, and 19 into field “c”.
Question - Why does the program put 19 into card field “c”?
Question - What would happen if you changed the 10 and 9 to 100 and 90?
Extra Practice - Write a script that adds two numbers together and puts the answer into card field “e”.
Extra Challenge - Write a script that adds four numbers together and puts the answer into card field “e”. Lesson Four - The “Subtract” Command
Objective - Students will write scripts utilizing the “add” command.
1. Type the following script into Student Programmer:
on mouseUp
put 9 - 2 into card field “a”
end mouseUp
Student Programmer will put 7 into card field “a”.
2. Now, for something tricky! Type the following script into Student Programmer.
on mouseUp
ask “Enter a number”
put it into card field “a”
ask “Enter another number”
put it into card field “b”
answer “ Your two numbers add up to be” && card field “a” + card field “b”
end mouseUp
You’ve just created a calculator! Well, at least one that can add. The “ask” command is very powerful, and you will learn more about it in later lessons.
Question - What does the “ask” command do? (It brings up a dialog box that you can type in).
Extra Practice - Write a script that subtracts two numbers and puts the answer into card field “a”.
Extra Challenge - Write a script that puts a different number into card fields “c ” and “d”, and then adds them together and puts the answer into card field “a”. Use the above script as an example.
Lesson Five - The “Answer” Command.
Objective - Students will understand how the “answer” command works, and will write scripts utilizing the “answer” command.
The answer command brings up a “dialog” box, with response buttons. The most common use for this is:
1. Try to duplicate the above dialog box by typing the following script:
on mouseUp
answer "Are you sure you want to quit?" with "Yes" or "No"
end mouseUp
HyperTalk is a very powerful language! In older computer languages, the above box might take 50 or more lines of code!
2. Here’s another example of the “answer” command. Try typing the following script into Stu Ådent Programmer:
on mouseUp
answer “Are you cool?”
end mouseUp
3. Now enter your own “answer” command. See if you can also program 2 responses, such as “Yes” or “No”. Notice that if you don’t program any choices for answers, HyperTalk gives you one choice: “OK”.
4. Now for the big challenge. Try typing this script into Student Programmer:
on mouseUp
answer “Are you cool? with “Yes” of “No”
if it is “Yes” then answer “No you’re not!”
if it is “No” then answer “Yes you are!”
end mouseUp
Run the script. You’ve just used a command and a statement - the “Answer” command and the “If/Then” statement. “The If/Then” statement will be the topic of the next lesson.
Extra Assignment - Write a script that contains 4 different answer commands in a row! (Hint - Your script should be 6 lines long).
Lesson 6 - The If/Then statement
Objective - Students will underst ¯and “if/then” logic, and will be able to write a script using an “if/then” statement.
1. Type in the following script:
on mouseUp
answer “Who is stronger, Superman or Spider Man?” with “Superman” or “Spider Man”
if it is “Superman” then answer “You are right!”
if it is “Spider Man” then answer “You are wrong!”
end mouseUp
The If/Then statement is conditional - If the user clicked on the “Superman” button then the program will answer “You are right!” In computer programming, we have a way of showing how this works:
If the
user clicks on
Superman Spider Man
Then answer Then answer
“You are right!” “You are wrong!”
If the user clicks on one button, then one event will happen. If they click on the other button, then a different event will happen. That’s why this is called an “If/Then” statement!
2. Now let’s try something more advanced. Type the script below into Student Programmer. Instead of the blank lines, write your own answers. Use the script from #1 (above) as an example.
on mouseUp
answer “Do you like computers?” with “Yes” or “No”
if it is “Yes” then answer “____________________________________”
if it is “No” then answer “ _____________________________________”
end mouseUp
Did you get your script to run? Good for you! If not, keep trying.
Lesson 7 - The If/Then Statement
Objective - Students will understand “if/then” logic, and will be able to write a script using an “if/then” statement.
1. Type the following script into Student Programmer:
on mouseUp
answer “Are you cool?” with “Yes” or “No”
if it is “Yes” then
answer “Are you sure?” with “Yes” or “No”
if it is “Yes” then answer “Sure you are!”
if it is “No” then answer “You changed your mind.”
end if
if it is “No” then
answer “Don’t be so hard on yourself!”
answer “You’re cool. Honest you are.”
end if
end mouseUp
If you can get the above script to work, you’re doing well! Notice that the If/Then statements above start with “if it is “Yes” then... and end with “end if”. You can put an almost unlimited number of directions between the “if...” line and the “end if” line.
In problem number 3 (above), you can begin to see how scripts can quickly become complicated. It’s important to script slowly so that you understand what happening with each line.
Question - What does an “If/Then” statement do?
Question - How many directions can be between an “if” l ine and the “end if” line in a script?
Extra Practice - Make a script that contains an If/Then statement. Use the script above as an example.
Extra Credit - Make a script that contains more than one If/Then statement. Use the script above as an example.
Lesson 8 - The Repeat Loop
Objective - Students will understand repeat loops.
1. The repeat loop is one of the most powerful programming tools. Type the following script into Student Programmer:
on mouseUp
repeat for 5 times
answer “This is a test.”
end repeat
end mouseUp
When you run this script, you will be forced to click the “OK” button 5 times.
2. Type the following script into Student Programmer:
on mouseUp
put 2 into card field “a”
repeat for 20 times
add 2 to card field “a”
end repeat
end mouseUp
What did it do? If you programmed it correctly, it put 2 into card field “a” and then added 2 to that number 20 times!
DANGER! - The repeat loop is the beginning programmer’s worst nightmare when used incorrectly!
DO NOT TYPE THE FOLLOWING SCRIPT INTO STUDENT PROGRAMMER!
on mouseUp
repeat
answer “How are you?” with “Fine.”
end repeat
end mouseUp
What would happen if you ran that script? Without telling the computer how many times to repeat, the computer would repeat forever.
IF YOU ACCIDENTALLY WRITE A BAD REPEAT LOOP, DO THIS: Hold the “Command Key” down and press the “.” (period) key. This will automatically stop your script from running!
Question - What does the repeat loop do?
Question - Why do we have to tell the repeat loop how many times to repeat?
Lesson 9 - The Repeat Loop + the If/Then Statement
Objective - Students will combine a repeat loop with an “if/then” statement.
Computer programming is all about combining commands to do different things! Here’s a cool script you can try:
on mouseUp
repeat
answer “Are you happy?” with “Yes” or “No”
if it is “Yes” then exit repeat
if it is “No” then
answer “You need t o be happy!”
answer “Life is too short to be sad!”
answer “Try to be happy all of the time...”
answer “and you will be so glad!”
end if
end repeat
answer “I’m glad you’re happy!”
end mouseUp
What happens when you run this script? The computer will not let you out of the repeat loop until you click the “Yes” button. When you do that, the “exit repeat” command is given. This is another way to get out of a repeat loop!
Question - What does the above script do when the user clicks the “Yes” button?
Extra Practice - Write a script containing a repeat loop AND an “if/then” statement.
Extra Credit - Write a script containing a repeat loop and 2 “if/then”statements!
Lesson 10 - Advanced Projec t
Objective - Students will enter a script and then modify it to suit their needs.
Below is a script. Enter it into Student Programmer, and then (after you’ve gotten it to run) feel free to modify it!
IMPORTANT! When you come to the end of the line, keep typing. Even though the line will wrap, it will still be considered part of the same line.
on mouseUp
answer “Wacky Psychiatrist by R. MacLemale”
ask “Hello. What is your name?”
put it into newName
ask “Pleased to meet you,” && newName & “. What seems to be the problem?”
put it into problem
ask “So when you say” && problem && “, aren’t you really saying you are silly?”
ask “Why do you say” && it & “?”
answer “There’s no reason to talk that way!”
answer “Is this problem a little problem or a big problem?” with “Little” or “Big”
if it is “Little” then
ask “Why are you bugging me with such a little problem?”
answer “Well you need to get a grip! Take two aspirin and swallow a car.”
else
answer “Ooooo, a BIG problem. You think you’ve got a big problem?” with “Yes”
answer “So” && quote & problem & quote && “is a big problem?” with “Yes”
answer “I guess it is. Drink a glass of water and read a book.”
end if
answer “Would you like to argue?” with “Yes” or “No”
if it is “Yes” then
repeat
answer “Are you a loser?” with “Yes” or “No”
if it is “No” then
answer “Yes you are!” with “No way!”
else
answer “No you’re not!”
exit repeat
end if
end repeat
end if
answer “That will be three thousand dollars, please.” with “No”
end mouseUp
Lesson 11 - Advanced Project
Objective - Students will enter a script and then modify it to suit their needs.
Below is a script. Enter it into Student Programmer, and then (after you’ve gotten it to run) feel free to modify it! d
IMPORTANT! When you come to the end of the line, keep typing. Even though the line will wrap, it will still be considered part of the same line.
on mouseUp
answer “Magic 8 Ball Simulation by R. MacLemale.”
ask “What is your name?”
put it into name
repeat
ask “Please type a yes or no question,” && name & “:”
set cursor to watch
wait 3 seconds
put random(6) into thisAnswer
if thisAnswer = 1 then answer “My sources say no.”
if thisAnswer = 2 then answer “Count on it!”
if thisAnswer = 3 then answer “No.”
if thisAnswer = 4 then answer “Yes.”
if thisAnswer = 5 then answer “Ask again later.”
if thisAnswer = 6 then answer “You bet!”
answer “That was fun. Would you like to ask another question?” with “Yes” or “No”
if it is “No” then exit to HyperCard
end repeat
end mouseUp
Can you modify this script to include up to 8 responses?
