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https://git.sr.ht/~crc_/retroforth
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37 lines
1.2 KiB
Forth
37 lines
1.2 KiB
Forth
# Lightweight Flow Control
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These were adapted from HerkForth.
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| 0=; | n- | exit word if TOS = 0 |
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| 0<>; | n- | exit word if TOS <> 0 |
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| <; | nn- | exit word if NOS < TOS |
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| >; | nn- | exit word if NOS > TOS |
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| <>; | nn- | exit word if NOS <> TOS |
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| if; | f- | exit word if TOS is TRUE |
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| ?; | f- | exit word if TOS is TRUE. Leave Flag on stack if TRUE. |
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~~~
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:0=; n:zero? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
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:0<>; n:zero? [ as{ 'popopodr i 'drdrre.. i }as ] -if ;
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:<; lt? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
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:>; gt? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
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:<>; -eq? [ as{ 'popopodr i 'drdrre.. i }as ] if ;
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:if; [ as{ 'popopodr i 'drdrre.. i }as ] if ;
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:?; dup [ as{ 'popopodr i 'drdrre.. i }as ] if drop ;
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~~~
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# Tests
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```
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:test (n-) n:even? if; 'Odd! s:put nl ;
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#1 test
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#2 test
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```
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```
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nl '----------------- s:put nl
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:test (n-) n:even? ?; 'Odd! s:put nl ;
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#1 test dump-stack reset nl
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#2 test dump-stack reset nl
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```
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