syntax

问题 In this question I asked about a method to explicitly prevent passed arguments to change. An obvious solutions is defining copys of the arguments and operate the algorithm on those copys. However in the comment I was pointed to the fact, that I could call the function and wrapp the argument I didn't want to change in brackets. This would have the same effect as creating a copy of that passed variables so that it would not change. But I don't understand how it works and what the brackets are

问题 In this question I asked about a method to explicitly prevent passed arguments to change. An obvious solutions is defining copys of the arguments and operate the algorithm on those copys. However in the comment I was pointed to the fact, that I could call the function and wrapp the argument I didn't want to change in brackets. This would have the same effect as creating a copy of that passed variables so that it would not change. But I don't understand how it works and what the brackets are

问题 total_cost_of_food = float(input('How much did the food cost? ')) sales_tax = 8.25 tax_plus_total = total_cost_of_food * sales_tax / 100 print("Your tax for this meal was:", tax_plus_total) x = bool(input("Would you like to add a tip? ") if x is False print("Thanks, your total for today is:", tax_plus_total) else print("That is", x, "I would like to add a tip") I keep getting this error for my print statement that is under the if statement, it says it's a syntax error but I don't see anything

问题 I am having trouble trying to understand pattern matching rules in Rust. I originally thought that the idea behind patterns are to match the left-hand side and right-hand side like so: struct S { x: i32, y: (i32, i32) } let S { x: a, y: (b, c) } = S { x: 1, y: (2, 3) }; // `a` matches `1`, `(b, c)` matches `(2, 3)` However, when we want to bind a reference to a value on the right-hand side, we need to use the ref keyword. let &(ref a, ref b) = &(3, 4); This feels rather inconsistent. Why can

问题 I am having trouble trying to understand pattern matching rules in Rust. I originally thought that the idea behind patterns are to match the left-hand side and right-hand side like so: struct S { x: i32, y: (i32, i32) } let S { x: a, y: (b, c) } = S { x: 1, y: (2, 3) }; // `a` matches `1`, `(b, c)` matches `(2, 3)` However, when we want to bind a reference to a value on the right-hand side, we need to use the ref keyword. let &(ref a, ref b) = &(3, 4); This feels rather inconsistent. Why can

问题 What does data_mux mean here? Is it just a name for the block? if ((PORT_CONFIG == "32") && (P0 == 1'b1)) begin : data_mux ... end 回答1: These are block names. Especially useful with generate blocks. For example you can define a generate block such as genvar i; generate (for i = 0; i<10; i++) begin : structures reg my_reg; // ... .. other block descriptions // ... end endgenerate Then you can access the block elements later like structures[3].my_reg <= 1'b1; 回答2: Yes, it is just the name for

问题 What does data_mux mean here? Is it just a name for the block? if ((PORT_CONFIG == "32") && (P0 == 1'b1)) begin : data_mux ... end 回答1: These are block names. Especially useful with generate blocks. For example you can define a generate block such as genvar i; generate (for i = 0; i<10; i++) begin : structures reg my_reg; // ... .. other block descriptions // ... end endgenerate Then you can access the block elements later like structures[3].my_reg <= 1'b1; 回答2: Yes, it is just the name for

问题 What does data_mux mean here? Is it just a name for the block? if ((PORT_CONFIG == "32") && (P0 == 1'b1)) begin : data_mux ... end 回答1: These are block names. Especially useful with generate blocks. For example you can define a generate block such as genvar i; generate (for i = 0; i<10; i++) begin : structures reg my_reg; // ... .. other block descriptions // ... end endgenerate Then you can access the block elements later like structures[3].my_reg <= 1'b1; 回答2: Yes, it is just the name for

问题 What does data_mux mean here? Is it just a name for the block? if ((PORT_CONFIG == "32") && (P0 == 1'b1)) begin : data_mux ... end 回答1: These are block names. Especially useful with generate blocks. For example you can define a generate block such as genvar i; generate (for i = 0; i<10; i++) begin : structures reg my_reg; // ... .. other block descriptions // ... end endgenerate Then you can access the block elements later like structures[3].my_reg <= 1'b1; 回答2: Yes, it is just the name for

问题 This is a follow-on to this answer to this question. When this code is saved to a file and run from the command line, it prints 13 three times. Twice I can understand, but three times? Why? When I run it from racket-mode in emacs it prints 13 five times! And when I run it in DrRacket it prints 13 seven times! The behaviour is also different in vanilla Racket? Changing #lang typed/racket to #lang racket prints 13 once from the command line, twice from emacs and three times from DrRacket. What