Grammar and language summary and comb

1. carding second chapter, understand and write a summary.

2. Try to write grammar PL / 0 language. (Or do you think the better language rules)

Integer

S-->0|1|2|3|……|8|9|N

N-->|1|2|3|……|8|9|ND

D-->S

I identifier

　　i->a|b|c|……|y|z|A|B|C|……|Y|Z

Expression e

　<Expression> -> [+ | -] <item> {<subtraction operator> <item>} /

Conditional statements

　<Conditional statements> -> if <condition> then <statement>

Assignment

　　i = e

Compound statement

　　stmt-> begin <statement> {; <statement>} end

　　<Statement> -> <assignment> | <conditional statements> | <When the loop type> | <procedure call statement> | <statement read> | <Write statement> | <compound statement> | <empty statement>

function

　　<Function> -> <Modifier> <parameter> <return type> <function name> <Method> The

　　<Modifier> -> public | static | ... |

　　<Parameter> -> lag | null

　　<Return type> -> int | String | char | ... | void

　　<Function name> ---> String | ...