PS TEXT FORMAT Reference Manual

Escape Sequences
11387 Tandem Computers Incorporated 4-13
For a command that can evaluate its own expressions (such as ASSIGN
or FILE WRITE), it's best to use the expression alone, without any
indirection. However, if the expression yields a numeric value and a
string is required, you can use either the indirection escape sequence or
the STRING function (see Section 5) to convert the numeric value to a
string type.
For example, given the following source lines:
66. \ASSIGN tsuris "worry worry worry"
67. \FILE WRITE * \\(tsuris\\)
68. \FILE WRITE * \(tsuris\)
69. \FILE WRITE * tsuris
Pre-execution scan evaluates the three FILE WRITE commands to:
\FILE WRITE \(tsuris\)
\FILE WRITE worry worry worry
\FILE WRITE "worry worry worry"
When TFORM tries to execute these commands, the first two commands
cause syntax errors. The first is an error because \(tsuris\) is an invalid
variable name (a name must begin with a letter and can't contain characters
like backslashes or parentheses). The second is an error because TFORM
sees the three words as variable names separated by spaces and because
the FILE WRITE command requires its entities to be separated by commas
(WORRY is probably an undefined variable as well). The third command
works, printing the string “worry worry worry,” because TFORM had
stored this string from the ASSIGN command in line 66.