Control Flow

Conditionals use the if and else keywords, and loops use while. The conditional expression is not wrapped with parentheses (though you can, of course, wrap any expression with parens). Braces are required around the body, with one exception for else (discussed below). We love counting parentheses:

int i = 0;
int f = 0;
char c = getchar();
while c >= 0 {
    i = i + 1;
    if c == '(' {
        f = f + 1;
    }
    c = getchar();
}

Semicolons are required to terminate statements which don't take a block. Blocks are not statements as is normal in C-family languages; they're parts of the if and while syntax. As well as not establishing scope, you can't have anonymous blocks (they would be of zero value). This will change, so don't abuse it.

Conditionals

An isolated if statement:

int f = 0;
char c = getchar();
if c == '+' {
    f = f + 1;
}

You can use else to do something else if the if's condition evaluates to false:

int f = 0;
char c = getchar();
if c == '+' {
    f = f + 1;
} else {
    eprintf("Unrecognized '%c'\n", c);
}

If an else's body is a single if statement, you can omit the braces. All the braces in the example below are required. There is an implied { after the first else, and an implied } at the very end. In English, the second else is "part of" the second if, which is the single if comprising the body of the first if's else. No dangling-else ambiguity!

int f = 0;
char c = getchar();
if c == '+' {
    f = f + 1;
} else if c == '-' {
    f = f - 1;
} else {
    eprintf("Unrecognized '%c'\n", c);
}

Loops

You can use done and again within a while to ... say you're done looping or want to loop again. These two snippets are equivalent:

# the reasonable way
char c;
while c >= 0 {
    c = getchar();
}

# the silly way
while true {
    if c >= 0 {
        c = getchar();
        again;
    }
    done;
}

Nesting depth is no longer constrained, but don't abuse it. Future you will thank you.