THE HYPERCARD CENTER

HyperTalk Reference

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Writing function handlers

When you write a handler for a function, you specify statements that compute and return a value to the handler that calls the function. Each function handler has the following form, where the italicized words are placeholders:

HyperCard has many built-in functions, but you can also write your own:

The function square receives a number through its parameter variable, x. It then returns the value of x * x to the handler that called it (mouseUp) using the return keyword.

Related Topics

• function
• The building blocks
• Using parameter variables

Placeholders

functionName

Any text string, without quotation marks, that represents the name of the function handler you want to write:

As in the HyperTalk examples:

statements

Any return-separated list of built-in commands, user-defined handlers, or keywords that are part of a message or function handler.