update std lib to use error type and global variables

example/guess_number/main.zig

@@ -3,45 +3,33 @@ export executable "guess_number";
 import "std.zig";
 import "rand.zig";
 
-error GetRandomFail;
-error ReadInputFail;
-
 pub fn main(args: [][]u8) %void => {
-    print_str("Welcome to the Guess Number Game in Zig.\n");
+    stderr.print_str("Welcome to the Guess Number Game in Zig.\n");
 
     var seed : u32;
-    const seed_bytes = (&u8)(&seed)[0...@sizeof(u32)];
-    const err = os_get_random_bytes(seed_bytes);
-    if (err != @sizeof(u32)) {
-        // TODO full error message
-        fprint_str(stderr_fileno, "unable to get random bytes\n");
-        return error.GetRandomFail;
-    }
+    const seed_bytes = (&u8)(&seed)[0...4];
+    os_get_random_bytes(seed_bytes);
 
     var rand = rand_new(seed);
 
     const answer = rand.range_u64(0, 100) + 1;
 
     while (true) {
-        print_str("\nGuess a number between 1 and 100: ");
+        stderr.print_str("\nGuess a number between 1 and 100: ");
         var line_buf : [20]u8;
-        var line_len : isize;
-        // TODO fix this awkward error handling
-        if (readline(line_buf, &line_len) || line_len == line_buf.len) {
-            // TODO full error message
-            fprint_str(stderr_fileno, "unable to read input\n");
-            return error.ReadInputFail;
-        }
+
+        // TODO print error message instead of returning
+        const line_len = %return stdin.readline(line_buf);
 
         var guess : u64;
         if (parse_u64(line_buf[0...line_len - 1], 10, &guess)) {
-            print_str("Invalid number format.\n");
+            stderr.print_str("Invalid number format.\n");
         } else if (guess > answer) {
-            print_str("Guess lower.\n");
+            stderr.print_str("Guess lower.\n");
         } else if (guess < answer) {
-            print_str("Guess higher.\n");
+            stderr.print_str("Guess higher.\n");
         } else {
-            print_str("You win!\n");
+            stderr.print_str("You win!\n");
             return;
         }
     }

example/hello_world/hello.zig

@@ -3,6 +3,5 @@ export executable "hello";
 import "std.zig";
 
 pub fn main(args: [][]u8) %void => {
-    //stderr.print_str("Hello, world!\n");
-    print_str("Hello, world!\n");
+    stdout.printf("Hello, world!\n");
 }

example/multiple_files/foo.zig

@@ -3,7 +3,7 @@ import "std.zig";
 // purposefully conflicting function with main.zig
 // but it's private so it should be OK
 fn private_function() => {
-    print_str("OK 1\n");
+    stdout.printf("OK 1\n");
 }
 
 pub fn print_text() => {

example/multiple_files/main.zig

@@ -5,7 +5,7 @@ import "foo.zig";
 
 pub fn main(args: [][]u8) i32 => {
     private_function();
-    print_str("OK 2\n");
+    stdout.printf("OK 2\n");
     return 0;
 }
 

example/shared_library/mathtest.zig

@@ -1,10 +1,10 @@
 #version("2.0.0")
 export library "mathtest";
 
-export fn add(a: i32, b: i32) -> i32 {
+export fn add(a: i32, b: i32) i32 => {
     a + b
 }
 
-export fn hang() -> unreachable {
-entry: goto entry;
+export fn hang() unreachable => {
+    while (true) { }
 }