Handbook
Glossary
Conditional combinators
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Combinators
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Dataflow combinators
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Looping combinators
The basic conditionals:
if
( ..a ? true: ( ..a -- ..b ) false: ( ..a -- ..b ) -- ..b )
when
( ..a ? true: ( ..a -- ..a ) -- ..a )
unless
( ..a ? false: ( ..a -- ..a ) -- ..a )
Forms abstracting a common stack shuffle pattern:
if*
( ..a ? true: ( ..a ? -- ..b ) false: ( ..a -- ..b ) -- ..b )
when*
( ..a ? true: ( ..a ? -- ..a ) -- ..a )
unless*
( ..a ? false: ( ..a -- ..a x ) -- ..a x )
Another form abstracting a common stack shuffle pattern:
?if
( ..a default cond: ( default -- new/f ) true: ( ..a new -- ..b ) false: ( ..a default -- ..b ) -- ..b )
?when
( ..a default cond: ( ..a default -- ..a new/f ) true: ( ..a new -- ..b ) -- ..b )
?unless
( ..a default cond: ( ..a default -- ..a new/f ) false: ( ..a default -- ..b ) -- ..b )
Sometimes instead of branching, you just need to pick one of two values:
?
( ? true false -- true/false )
Two combinators which abstract out nested chains of
if
:
cond
( assoc -- )
case
( obj assoc -- )
Expressing conditionals with boolean logic
See also
Booleans
,
Bitwise arithmetic
,
both?
,
either?