We just made quite important change in the string management in Scilab.
We (Allan and I) just switched the default string management. By
default, the trunk version of Scilab is using Cong Wu's work for both
Windows and Linux version.
Under Linux/Unix, the previous version is still available using the
option --with-string-v1 in the configure.
Cong rewrote all the string functions in C with a significant help of
Allan. The code is much easier to maintain and understand.
He also extended the string capabilities of Scilab especially providing
regular expression features (based on PCRE ) into Scilab.
The name of the module will change before the release of the alpha
version (probably STRING_V2 => string).
The source code is available on the viewvc  and on the SVN in the
directory SCI/modules/STRING_V2/ .
Many tests have been developed in order to ensure the maximun
compatibility between Scilab 4.X and Scilab 5.X string functions.
The next step for this module will be performance improvements.
Don't hesitate if you have any questions,