Selected keywords

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 : str

  The &clock read-only keyword produces the current time of day.

• &cset : cset

  The &cset constant keyword denotes the cset containing everything.

• &date : str

  The &date read-only keyword produces the current date.

• &digits : cset

  The &digits constant keyword denotes the cset containing 0 through 9.

• &errout : file

  The &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...