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Monads/Maybe monad: Difference between revisions

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Monads/Maybe monad (view source)

Revision as of 17:12, 12 May 2021

3,867 bytes added ,  3 years ago
m
→‎{{header|Phix}}: added syntax colouring the hard way
m (Corrected Python output)
m (→‎{{header|Phix}}: added syntax colouring the hard way)
Line 1,047:
Phix has an "object" type which can be an integer or a string, so not entirely un-like Perl.<br>
Here we simply treat all strings or rather non-integers as the "unknown" type.
<!--<lang Phix>function bind(object m, integer fphixonline)-->
<span style="color: #008080;">function</span> <span style="color: #000000;">bindf</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">)</span>
return f(m)
<span style="color: #008080;">return</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">(</span><span style="color: #000000;">m</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function unit(object m)
<span style="color: #008080;">function</span> <span style="color: #000000;">unit</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">)</span>
return m
<span style="color: #008080;">return</span> <span style="color: #000000;">m</span>
end function
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function times_five(object l)
<span style="color: #008080;">function</span> <span style="color: #000000;">times_five</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">l</span><span style="color: #0000FF;">)</span>
return iff(integer(l)?l*5:l)
<span style="color: #008080;">return</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span><span style="color: #0000FF;">(</span><span style="color: #000000;">l</span><span style="color: #0000FF;">)?</span><span style="color: #000000;">l</span><span style="color: #0000FF;">*</span><span style="color: #000000;">5</span><span style="color: #0000FF;">:</span><span style="color: #000000;">l</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function plus_four(object l)
<span style="color: #008080;">function</span> <span style="color: #000000;">plus_four</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">l</span><span style="color: #0000FF;">)</span>
return iff(integer(l)?l+4:l)
<span style="color: #008080;">return</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span><span style="color: #0000FF;">(</span><span style="color: #000000;">l</span><span style="color: #0000FF;">)?</span><span style="color: #000000;">l</span><span style="color: #0000FF;">+</span><span style="color: #000000;">4</span><span style="color: #0000FF;">:</span><span style="color: #000000;">l</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
 
procedure test(object l)
<span style="color: #008080;">procedure</span> <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">l</span><span style="color: #0000FF;">)</span>
printf(1,"%v -> %v\n", {l, bind(bind(l,times_five),plus_four)})
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%v -&gt; %v\n"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">l</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">bindf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">bindf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">l</span><span style="color: #0000FF;">,</span><span style="color: #000000;">times_five</span><span style="color: #0000FF;">),</span><span style="color: #000000;">plus_four</span><span style="color: #0000FF;">)})</span>
end procedure
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
test(3)
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">3</span><span style="color: #0000FF;">)</span>
test("none")</lang>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"none"</span><span style="color: #0000FF;">)</span>
<!--</lang>-->
{{out}}
<pre>
Petelomax
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