/path/to/parser3 script_file
x:\path\to\parser3 script_file
You can use Parser to interpret scripts with no web-server running. In this case you will just need to run Parser in command line with parameter-name of script to be interpreted. In this case, current directory will be considered web-space root.
Errors will get into standard error stream, which can be redirected to needed file:
command 2>>error_log
Note: do not forget to clean it up between whiles.
When working under UNIX, one can also take standard approach, which is specifying path to interpreter in script's first line:
#!/path/to/parser3
#your code
Check: ^eval(2*2)
Note: do not forget to set attributes allowing owner/user group to run the script. It can be done with:
chmod ug+x file