What is the significance of the “1” in LR(1)? Why might we want (or need) different grammars for different parsing algorithms? What is an epsilon production? What are recursive descent parsers? Why...

What is the significance of the “1” in LR(1)? Why might we want (or need) different grammars for different parsing algorithms? What is an epsilon production? What are recursive descent parsers? Why are they used mostly for small languages? How might a parser construct an explicit parse tree or syntax tree?