Parens free `if` statement

if.macro.sjs

/*

`if cond {}`

Brackets are mandatory, except when `if` is followed by specials keywords (return, break and continue)

```
if cond return
if cond break [label]
if cond continue [label]
```

*/

let if = macro {
  rule { $cond:expr { $body ... } } => {
    if ($cond) { $body ... }
  }
  rule { $cond:expr ; } => {
  	if ($cond);
  }
  rule { $cond:expr return $return:expr } => {
  	if ($cond) return $return 
  }
  rule { $cond:expr return } => {
  	if ($cond) return 
  }
  rule { $cond:expr continue $label:ident } => {
  	if ($cond) continue $label 
  }
  rule { $cond:expr continue } => {
  	if ($cond) continue 
  }
  rule { $cond:expr break $label:ident } => {
  	if ($cond) break $label 
  }
  rule { $cond:expr break } => {
  	if ($cond) break 
  }
  rule { $cond:expr do $body } => {
    if ($cond) do $body
  } 
}
 
export if;