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Book Overview & Buying
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Table Of Contents
Build Your Own Programming Language
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Unicon has about 75 keywords. Keywords are global names beginning with an ampersand with a predefined meaning. Many keywords are constant values that are built into the language, while others are associated with built-in domain-specific language facilities such as string scanning or graphics. This section lists the most essential keywords, many of which appear in the examples in this book:
&clock : strThe &clock read-only keyword produces the current time of day.
&cset : csetThe &cset constant keyword denotes the cset containing everything.
&date : strThe &date read-only keyword produces the current date.
&digits : csetThe &digits constant keyword denotes the cset containing 0 through 9.
&errout : fileThe &errout constant keyword denotes the standard location for error output.
&fail :The &fail keyword is an expression that fails to produce a result.
&features : str*The &features...