idlwave-abbrev-start-char

idlwave-abbrev-start-char is a variable defined in `idlwave.el'.
Its value is

"\\"

Documentation:
A single character string used to start abbreviations in abbrev mode.
Possible characters to chose from: ~`%
or even '?'. '.' is not a good choice because it can make structure
field names act like abbrevs in certain circumstances.

Changes to this in `idlwave-mode-hook' will have no effect. Instead a user
must set it directly using `setq' in the init file before idlwave.el
is loaded.

You can customize this variable.