Comment on Managing your Script
Krishnan,
Code for parabolic Sar Crossover: CLOSE > PSAR (CLOSE, 0.02, 0.2) AND REF (CLOSE, 1) < REF (PSAR (CLOSE, 0.02, 0.2), 1)
You can also look at our tutorial blog, bunch of queries on parabolic SAR already answered. http://www.zerodha.com/z-connect/blog/view/code-your-technical-analysis-strategy