retroforth/example/LightWeightFlowControl.forth

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These are adapted from HerkForth.
| 0= | n- | exit word if TOS = 0 |
| <; | nn- | exit word if NOS < TOS |
| >; | nn- | exit word if NOS > TOS |
| <>; | nn- | exit word if NOS <> TOS |
| if; | f- | exit word if TOS is TRUE |
| ?; | f- | exit word if TOS is TRUE. Leave Flag on stack if TRUE. |
~~~
:0=; n:zero? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
:<; lt? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
:>; gt? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
:<>; -eq? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
:if; [ as{ 'popopodr i 'drdrre.. i }as ] if ;
:?; dup [ as{ 'popopodr i 'drdrre.. i }as ] if drop ;
~~~
```
:test (n-) n:even? if; 'Odd! s:put nl ;
#1 test
#2 test
```
```
nl '----------------- s:put nl
:test (n-) n:even? ?; 'Odd! s:put nl ;
#1 test dump-stack reset nl
#2 test dump-stack reset nl
```