grammar.txt

来自「how to create a compiler」· 文本 代码 · 共 24 行

<stmt> := var <ident> = <expr>
	| <ident> = <expr>
	| for <ident> = <expr> to <expr> do <stmt> end
	| read_int <ident>
	| print <expr>
	| <stmt> ; <stmt>

<expr> := <string>
	| <int>
	| <arith_expr>
	| <ident>

<bin_expr> := <expr> <bin_op> <expr>
<bin_op> := + | - | * | /

<ident> := <char> <ident_rest>*
<ident_rest> := <char> | <digit>

<int> := <digit>+
<digit> := 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

<string> := " <string_elem>* "
<string_elem> := <any char other than ">