What are some good pointers to build a text analysis software? -

is there way check sentiments in text? trying build chat client should analyse text , able determine mood of user

you can try using classification, such described in data mining scientific field. can example train support-vector machine (svm) , use classification. here 2 papers found using approach on blog text:

• understanding how bloggers feel: recognizing affect in blog posts
• a hybrid mood classification approach blog text

and here classification approach using features known psychology doesn't require training of model:

• mood sensing social media texts , applications