Useless instructions: Difference between revisions
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→{{header|Phix}}: added some actrual code
(→{{header|ALGOL 68}}: Updated for the latest version of Algol 68G) |
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stand for "all become equal to". Technically it just about worked when x was a literal integer, but was badly
broken in almost every other sense, and from the 0 bug reports clearly had never been used in the real world.
<!--<lang Phix>(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">3</span>
<span style="color: #004080;">object</span> <span style="color: #000000;">i2</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">3</span> <span style="color: #000080;font-style:italic;">// same apart from error reporting</span>
<span style="color: #004080;">int</span> <span style="color: #000000;">i_too</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">3</span> <span style="color: #000080;font-style:italic;">// int is just an alias of integer
-- six different ways to set i to 3:</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0b11</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0(2)11</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0(36)3</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">#3</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0x3</span>
<span style="color: #000080;font-style:italic;">--i = '\x03' -- (ah, not pwa/p2js)</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">3</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">3</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">,</span><span style="color: #000000;">5</span><span style="color: #0000FF;">}</span>
<span style="color: #000080;font-style:italic;">-- four ways to print the first two</span>
<span style="color: #0000FF;">?</span><span style="color: #7060A8;">head</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)</span>
<span style="color: #0000FF;">?</span><span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">2</span><span style="color: #0000FF;">]</span>
<span style="color: #7060A8;">pp</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">2</span><span style="color: #0000FF;">])</span>
<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\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">2</span><span style="color: #0000FF;">]})</span>
<span style="color: #000080;font-style:italic;">-- two ways to append a 3</span>
<span style="color: #0000FF;">?{</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">}&</span><span style="color: #000000;">3</span>
<span style="color: #0000FF;">?</span><span style="color: #7060A8;">append</span><span style="color: #0000FF;">({</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">},</span><span style="color: #000000;">3</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- (nb same only when appending a single number)</span>
<span style="color: #008080;">if</span> <span style="color: #004600;">true</span> <span style="color: #008080;">then</span>
<span style="color: #000080;font-style:italic;">// do something</span>
<span style="color: #008080;">else</span>
<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;">"Never called\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">0</span> <span style="color: #008080;">do</span>
<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;">"Never called\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">while</span> <span style="color: #004600;">false</span> <span style="color: #008080;">do</span>
<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;">"Never called\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<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;">""</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- (On Windows, will create a console if one not already attached)</span>
<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;">"Working OK.\n"</span><span style="color: #0000FF;">)</span>
<!--</lang>-->
<small>(In fact, if you run "p -d test.exw" on the above, <code>if true</code> .. <code>end while</code> only emits a single instruction, <code>mov i,3</code> at the start of the for loop, and no other instructions at all for those thirteen lines.)</small><br>
<small>(Also, for the above and this by inspecting the list.asm file created, you would be able to see that it doesn't bother adding 3 to i, but instead simply sets it to 6 then 9.)</small><br>
{{out}}
<pre>
{1,2}
{1,2}
{1,2}
{1,2}
{1,2,3}
{1,2,3}
Working OK.
</pre>
=={{header|Raku}}==
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