Local Words

It would be helpful to let local variables create local words. So, instead of being put on the stack like a local variable, local words will run. There are two ways to do this in Smojo:

  • Bind the XT to a local variable as usual using 
    {
    and 
    }
    , then use 
    EXECUTE
    to run it as needed.
  • Use the word 
    ~
    to convert the XT to a local word instead so that it is run when called. This is the preferred method.

    • Example 1 
    	: make-greeting ( "greeting" -- xt ) { g } [: g . ;] ;
	
	"Hello Sam!" make-greeting dup 
 	
	: how-are { xt } "I would like to say " . xt execute ;
	
	how-are 
	I would like to say Hello Sam! ok
	
	: how-are ~ { fn } "I say: " . fn ;
	how-are
	I say: Hello Sam! ok
    Example 2 
    	: xx 	
		[: "hello" . ;] ~ { f }
		f f f 
	;
	
	xx
	hello hello hello ok

    Quiz

    Question 1

    Write a version of 
    HOW-ARE
     that does not use either local variables or local words.
    
	
	
	

    
	
	
	
    Question 2
    
	
    Write a word 
    FIND-MAX ( xt a b -- v )
     that takes a XT and two values as arguments. The XT is a single-value function of the form f(x).
	The word should return the maximum value between f(a) and f(b).
    
	
	
	

    
	
 
    Next: The Data Section