2: Simple example
4: Finer Control
5: X-Y Plots
6: Contour Plots
7: Image Plots
9: Gri Commands
12: Emacs Mode
15: Gri Bugs
16: Test Suite
17: Gri in Press
`assert .condition. ["message"]
The condition may be a variable, a synonym, or an RPN expression. If this condition is true (i.e. evaluates to a non-zero number), do nothing. If the condition is false, the program will terminate with an error condition (in unix, it will terminate with a non-zero exit code).
Before termination, a message will be printed, the form of which depends
on the optional `
If no `
"message"' string is given, the the printed message will
indicate the name of the command-file and the line at which the assert
command was encountered.
If a `
"message"' string is given, and if it ends in a newline
"\\n"'), then this string is printed.
If a `
"message"' string is given, and if it does not end in
"\\n"', then the string is printed along with an indication of the
location in the command-file.
(Perl users will recognize this as being patterned on the `