-
Book Overview & Buying
-
Table Of Contents
-
Feedback & Rating

Build Your Own Programming Language
By :

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...