refine code for useVar internal flag. stop using array on it.
try to support advvar (not done)
merge master
Merge branch 'master' into advanced_varname
try to support advvar when in useVar compile time. not tested, no error handling now
add advanced variable name checking in scan() stage
add test for error case
add example for small test script
now can report more than 1 error in template when compile()
add more error varname test
now detect advanced variable name error in scan() , add more test case in test/error.php
support adcanced variable name now (but not tested)
fix function. typo.
fix copy paste bugs, typo. now tested, seens good
fix for ../ bug
fix for ../../
fixed wrong variable name _vx logic and some json schema generator logic
fix wrong regexp