C String Switch - A switch-case alternative for strings

Keeping Going Automatically

Demo:

Considering we want to code something like below:

char ch[20];
scanf("%s", ch);
switch(string){
	case "hello":
		printf("Hi!\n");
		char name[20];
		scanf("%s", name);
		switch(name){
			case "Kevin":
				printf("Nice to meet you!\n");
			default:
				printf("But my name is \"Kevin\"!!!");
		}
	default:
		printf("Not Working\n");
	case "bye":
		printf("The end\n");
		break;
	case "err":
		printf("Error");
		goto default;
	case "sth":
		printf("What?");
}

... we are sure to find out it's impossible to work - things after case should be a constant, while a string is actually a address. The most common way is to do it like this:

if(strcmp(ch, "hello") == 0){
	//...
}else if(strcmp(ch, "bye")){
	//...
}else if(strcmp(ch, "err")){
	//...
}else{
	//...
}

However, obviously, a lot of if-else and repeated strcmp are indeed stressful. Also, reusing codes in blocks won't be easy, either. Thus, here comes the match-like block! It looks like below:

match(ch)
	like("hello")
		printf("Hi\n");
		char name[20];
		scanf("%s", name);
		match(name)
			like("Kevin")
				printf("Nice to meet you!\n");
				break;
			other
				printf("But my name is Kevin!\n");
		endMatch
		thenGo("bye");
	other
		printf("Not working\n");
	like("bye")
		printf("The end\n");
		break;
	like("err")
		printf("Error\n");
		thenGoOther;
	like("sth")
		printf("What?\n");
endMatch

This demo can be found in autoKeepGoing/demo.c.

Features:

• Code reusing (thenGo() and thenGoOther)
• Code reducing (needless to use strcmp)
• Scope safety (codes after each like() or other is actually contained by a { })

Usage:

The first step is to #include this library. Just put autoKeepGoing/matchLikeMacro.h under the same directory as main.c or something. Then, copy & paste this line into it:

 #include "matchLikeMacro.h"

A match-like block looks like this:

match(switchString)
	like("cmd1")
	like("cmd2")
	other
endMatch

It starts with match(switchString) and ends up with endMatch.

Each case started with like(identifierString) or other. A : must not be provided. A case will be run when the switchString matchs the identifierString, or after the cases preceding is done.

To escape the block, use break; . To force another case to be run, use thenGo(identifierString); or thenGoOther; .

Auto Break

For those who found a bunch of break; s are useless.

Given a code like this:

char ch[20];
scanf("%s", ch);

switch(ch){
	case "hello":
		printf("Hi\n");
		break;
	case "bye":
		printf("TheEnd!\n");
		break;
	case "err":
		printf("Weird.\n");
		goto default;
		break;
	default:
		printf("notWorking!\n");
		goto case "bye";
		break;
}

... on top of the impossibility of compiling and running, it is tiring to remember to use break;. Thus, here comes the meet-as block!

meet(ch)
	as("hello")
		printf("Hi\n");
	as("bye")
		printf("TheEnd!\n");
	as("err")
		printf("Weird.\n");
		forceMeetRest;
	rest
		printf("notWorking!\n");
		forceMeet("bye");
endMeet

Ha! Much cleaner, right?

Features:

• Code reusing (forceMeet() and forceMeetRest)
• Code reducing (needless to use strcmp and break; )
• Scope safety (codes after each as() or rest is actually contained by a { })

Usage:

Usage:

The first step is to #include this library. Just put autoBreak/meetAs.h under the same directory as main.c or something. Then, copy & paste this line into it:

#include "meetAs.h"

A meet-as block looks like this:

meet(switchString)
	as("cmd1")
	as("cmd2")
	other
endMeet

It starts with meet(switchString) and ends up with endMeet.

Each case started with as(identifierString) or rest. A : must not be provided. The rest block must always be at the end, right before endMeet. A case will be run when the switchString matchs the identifierString, or after the cases preceding is done.

To escape the block, use break; . To force another case to be run, use forceMeet(identifierString); or forceMeetOther; .