Listack program examples

Examples of different ways to do the same thing in Listack.

10 @>n	# set local variable n to 10
# The following all set the local variable a to (n+1)*2
n 1 .+ 2 .* @>a
n + 1 * 2 @>a
(n + 1 * 2) @>a
(n + 1) * 2 @>a
n.inc * 2 @>a
+: n 1 2 .* @>a
+(n 1) * 2 @>a
+(n,1)*2@>a
set(‘a’, (n + 1 * 2))
set: `a (n + 1 * 2)
“a” set (+: n 1 * 2)
\a (n 1 .+ 2 .*) .set
set(\a, *(+(n, 1), 2))
set(\a *(+(n 1) 2))
\a set (+: @<n 1 2 .*)
\n.get 1 .+ 2 .* @>a 
{n + 1 * 2} eval @>a
+: @*n 1 * 2 \a swap .set
# And many more, with increasing levels of obfuscation.

Computing the summation of 0..number

def: "summ" [Int]
  {dup <=>	# would be a bit faster if this were postfix
    {dup {1 .+ dup 0 .<} {dup roll .+ swap} .while}   # negative
    {dup}                                             		   # zero
    {dup {1 .- dup 0 .>} {dup roll .+ swap} .while}    # positive
  drop  }
timer_start 100_000 summ timer_check 	# timer works in nanoseconds
"summ(100,000) time: " print 1_000_000 .// print " ms" println 
println cr

def: "fast_summ" [Int]
  { dup # <=>		This is a good way to indicate what’s going on with postfix words.
    {dup 1 .- .* -2 .//}
    {nop}
    {dup 1 .+ .* 2 .//}
  .<=> }
timer_start 100_000 fast_summ timer_check 
"fast_summ(100,000) time: " print 1_000 .// print " us" println 
println

The following is the actual definition of 'while'.

# while
create_global: "_while_cond"
create_global: "_while_body"

# internal use only
def: "_while_" [] 
  {@!_while_cond 
  {@!_while_body _begin_loop_ 
   _while_}
  .iff}

# {condition to continue} while {body to execute}
# {true} while {println:"infinite loop"}

def: "while" [Blocky, Blocky] 
  {@>_while_body @>_while_cond 
  _while_ _end_loop_
  @<_while_body drop @<_while_cond drop}

def: "while" [Bool, Blocky] 
  {@>_while_body @>_while_cond 
  _while_ _end_loop_
  @<_while_body drop @<_while_cond drop}

def: "while" [Bool, Word] {>block .while}
def: "while" [Blocky, Word] {>block .while}

[3 5 7] {dup .+} {dup .*} bi_map
# produces: [6 10 14] [9 25 49]

[3 5 7] {dup .+} {dup .*} bi_each
# produces: 6 10 14 9 25 49

3 4 \sqr both .+ sqrt
# produces 5.0