unprotbas: handle corner case where 129 vars are in the table.

1 files changed, 22 insertions, 9 deletions

diff --git a/unprotbas.rst b/unprotbas.rst
index 752acd7..6ba560c 100644
--- a/unprotbas.rst
+++ b/unprotbas.rst
@@ -206,20 +206,33 @@ Load the unprotected program on the Atari and LIST it (or use **chkbas** to get
 listing), and edit **varnames.txt** in a text editor.
 
 As you figure out what each variable's purpose is, change its name
-in the text file. Don't delete any lines from the file, and don't
-add any. Don't get rid of the *$* or *(* at the end of any line. You
-may enter the names in lowercase (**unprotbas** will convert them to
-uppercase). Remember to follow the rules for BASIC variable names:
-only letters and numbers allowed, and the first character must be
-a letter. No duplicates of the same type are allowed (you can have
-*FOO* and *FOO$*, but not two numerics called *FOO*).
+in the text file. When editing the file:
+
+- Don't add or delete any lines.
+- Don't get rid of the *$* or *(* at the end of any line.
+- You may enter the names in lowercase (**unprotbas** will convert them to uppercase).
+- Remember to follow the rules for BASIC variable names:
+  The first character must be a letter, other characters must be a letter
+  or a number, and only the last character can be *$* or *(*.
+- No duplicates of the same type are allowed (you can have *FOO* and *FOO$*,
+  but not two numerics called *FOO*).
 
 When you're finished, re-run **unprotbas**, this time with the **-r**
-option. The unprotected program will use your variable names, rather
-than generating new ones.
+option. If all is well, the unprotected program will use your variable
+names, rather than generating new ones. If you broke the rules, you
+should get an informative error message explaining what and where the
+problem is.
 
 This process can also be used for regular unprotected programs. Use
 **-n -w** the first time, to save the existing variable names to
 **varnames.txt** rather than generating new ones.
 
+NOTES
+=====
+
+Atari BASIC has a limit of 128 variables in a program. It's actually
+possible for the variable name table (and the variable value table)
+to contain 129 variables, though the last one won't be usable in the
+program.
+
 .. include:: manftr.rst