RosettaCodeData/Task/Truth-table/Phix/truth-table.phix

(phixonline)-->
 <span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
 <span style="color: #008080;">constant</span> <span style="color: #000000;">bFT</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>    <span style="color: #000080;font-style:italic;">-- true: use F/T, false: use 0/1, as next</span>

 <span style="color: #008080;">function</span> <span style="color: #000000;">fmt</span><span style="color: #0000FF;">(</span><span style="color: #004080;">bool</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">return</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">bFT</span><span style="color: #0000FF;">?{</span><span style="color: #008000;">"F"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"T"</span><span style="color: #0000FF;">}:{</span><span style="color: #008000;">"0"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1"</span><span style="color: #0000FF;">})[</span><span style="color: #000000;">b</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>

 <span style="color: #004080;">sequence</span> <span style="color: #000000;">opstack</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
 <span style="color: #004080;">object</span> <span style="color: #000000;">token</span><span style="color: #0000FF;">,</span>
        <span style="color: #000000;">op</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>   <span style="color: #000080;font-style:italic;">-- 0 = none</span>
 <span style="color: #004080;">string</span> <span style="color: #000000;">s</span>        <span style="color: #000080;font-style:italic;">-- the expression being parsed</span>
 <span style="color: #004080;">integer</span> <span style="color: #000000;">sidx</span><span style="color: #0000FF;">,</span>   <span style="color: #000080;font-style:italic;">-- idx to ""</span>
         <span style="color: #000000;">ch</span>      <span style="color: #000080;font-style:italic;">-- s[sidx]</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">err</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">msg</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;">"%s\n%s^ %s\n\nPressEnter..."</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">s</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #008000;">' '</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">),</span><span style="color: #000000;">msg</span><span style="color: #0000FF;">})</span>
     <span style="color: #0000FF;">{}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">wait_key</span><span style="color: #0000FF;">()</span>
     <span style="color: #7060A8;">abort</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">)</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">nxtch</span><span style="color: #0000FF;">()</span>
     <span style="color: #000000;">sidx</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
     <span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">></span><span style="color: #7060A8;">length</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;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">])</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">skipspaces</span><span style="color: #0000FF;">()</span>
     <span style="color: #008080;">while</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">,</span><span style="color: #008000;">" \t\r\n"</span><span style="color: #0000FF;">)!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">do</span> <span style="color: #000000;">nxtch</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">get_token</span><span style="color: #0000FF;">()</span>
     <span style="color: #000000;">skipspaces</span><span style="color: #0000FF;">()</span>
     <span style="color: #008080;">if</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"()!"</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
         <span style="color: #000000;">token</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">..</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">]</span>
         <span style="color: #000000;">nxtch</span><span style="color: #0000FF;">()</span>
     <span style="color: #008080;">else</span>
         <span style="color: #004080;">integer</span> <span style="color: #000000;">tokstart</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">sidx</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=-</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">token</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"eof"</span> <span style="color: #008080;">return</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
             <span style="color: #000000;">nxtch</span><span style="color: #0000FF;">()</span>
             <span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;"><</span><span style="color: #008000;">'A'</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
         <span style="color: #000000;">token</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">tokstart</span><span style="color: #0000FF;">..</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">Match</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">t</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">token</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">t</span> <span style="color: #008080;">then</span> <span style="color: #000000;">err</span><span style="color: #0000FF;">(</span><span style="color: #000000;">t</span><span style="color: #0000FF;">&</span><span style="color: #008000;">" expected"</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #000000;">get_token</span><span style="color: #0000FF;">()</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">PopFactor</span><span style="color: #0000FF;">()</span>
     <span style="color: #004080;">object</span> <span style="color: #000000;">p2</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">opstack</span><span style="color: #0000FF;">[$]</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"not"</span> <span style="color: #008080;">then</span>
         <span style="color: #000000;">opstack</span><span style="color: #0000FF;">[$]</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">op</span><span style="color: #0000FF;">,</span><span style="color: #000000;">p2</span><span style="color: #0000FF;">}</span>
     <span style="color: #008080;">else</span>
         <span style="color: #000000;">opstack</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">opstack</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..$-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
         <span style="color: #000000;">opstack</span><span style="color: #0000FF;">[$]</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">opstack</span><span style="color: #0000FF;">[$],</span><span style="color: #000000;">op</span><span style="color: #0000FF;">,</span><span style="color: #000000;">p2</span><span style="color: #0000FF;">}</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #000000;">op</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #004080;">sequence</span> <span style="color: #000000;">names</span><span style="color: #0000FF;">,</span> <span style="color: #000080;font-style:italic;">-- {"false","true",...}</span>
          <span style="color: #000000;">flags</span>  <span style="color: #000080;font-style:italic;">-- {   0,     1,  ,...}</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">PushFactor</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">t</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #000000;">PopFactor</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #004080;">integer</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">t</span><span style="color: #0000FF;">,</span><span style="color: #000000;">names</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
         <span style="color: #000000;">names</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">names</span><span style="color: #0000FF;">,</span><span style="color: #000000;">t</span><span style="color: #0000FF;">)</span>
         <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">names</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #000000;">opstack</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">opstack</span><span style="color: #0000FF;">,</span><span style="color: #000000;">k</span><span style="color: #0000FF;">)</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">PushOp</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">t</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #000000;">PopFactor</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #000000;">op</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">t</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">forward</span> <span style="color: #008080;">procedure</span> <span style="color: #000000;">Expr</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">)</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">Factor</span><span style="color: #0000FF;">()</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">token</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"not"</span>
     <span style="color: #008080;">or</span> <span style="color: #000000;">token</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"!"</span> <span style="color: #008080;">then</span>
         <span style="color: #000000;">get_token</span><span style="color: #0000FF;">()</span>
         <span style="color: #000000;">Factor</span><span style="color: #0000FF;">()</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #000000;">PopFactor</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #000000;">PushOp</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"not"</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">elsif</span> <span style="color: #000000;">token</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"("</span> <span style="color: #008080;">then</span>
         <span style="color: #000000;">get_token</span><span style="color: #0000FF;">()</span>
         <span style="color: #000000;">Expr</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">)</span>
         <span style="color: #000000;">Match</span><span style="color: #0000FF;">(</span><span style="color: #008000;">")"</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">elsif</span> <span style="color: #008080;">not</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">token</span><span style="color: #0000FF;">,{</span><span style="color: #008000;">"and"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"or"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"xor"</span><span style="color: #0000FF;">})</span> <span style="color: #008080;">then</span>
         <span style="color: #000000;">PushFactor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">token</span><span style="color: #0000FF;">)</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">!=-</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span>
             <span style="color: #000000;">get_token</span><span style="color: #0000FF;">()</span>
         <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #008080;">else</span>
         <span style="color: #000000;">err</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"syntax error"</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">constant</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">operators</span><span style="color: #0000FF;">,</span>
           <span style="color: #000000;">precedence</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">columnize</span><span style="color: #0000FF;">({{</span><span style="color: #008000;">"not"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">6</span><span style="color: #0000FF;">},</span>
                                    <span style="color: #0000FF;">{</span><span style="color: #008000;">"and"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">5</span><span style="color: #0000FF;">},</span>
                                    <span style="color: #0000FF;">{</span><span style="color: #008000;">"xor"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">},</span>
                                    <span style="color: #0000FF;">{</span><span style="color: #008000;">"or"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">3</span><span style="color: #0000FF;">}})</span>
 <span style="color: #008080;">procedure</span> <span style="color: #000000;">Expr</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">)</span>
     <span style="color: #000000;">Factor</span><span style="color: #0000FF;">()</span>
     <span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
         <span style="color: #004080;">integer</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">token</span><span style="color: #0000FF;">,</span><span style="color: #000000;">operators</span><span style="color: #0000FF;">)</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #004080;">integer</span> <span style="color: #000000;">thisp</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">precedence</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">thisp</span><span style="color: #0000FF;"><</span><span style="color: #000000;">p</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #000000;">get_token</span><span style="color: #0000FF;">()</span>
         <span style="color: #000000;">Expr</span><span style="color: #0000FF;">(</span><span style="color: #000000;">thisp</span><span style="color: #0000FF;">)</span>
         <span style="color: #000000;">PushOp</span><span style="color: #0000FF;">(</span><span style="color: #000000;">operators</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">])</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #008080;">function</span> <span style="color: #000000;">evaluate</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #004080;">atom</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">>=</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">flags</span><span style="color: #0000FF;">[</span><span style="color: #000000;">s</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #008080;">return</span> <span style="color: #000000;">s</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #004080;">object</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">lhs</span><span style="color: #0000FF;">,</span><span style="color: #000000;">op</span><span style="color: #0000FF;">,</span><span style="color: #000000;">rhs</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span>
     <span style="color: #000000;">lhs</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">evaluate</span><span style="color: #0000FF;">(</span><span style="color: #000000;">lhs</span><span style="color: #0000FF;">)</span>
     <span style="color: #000000;">rhs</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">evaluate</span><span style="color: #0000FF;">(</span><span style="color: #000000;">rhs</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"and"</span> <span style="color: #008080;">then</span>
         <span style="color: #008080;">return</span> <span style="color: #000000;">lhs</span> <span style="color: #008080;">and</span> <span style="color: #000000;">rhs</span>
     <span style="color: #008080;">elsif</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"or"</span> <span style="color: #008080;">then</span>
         <span style="color: #008080;">return</span> <span style="color: #000000;">lhs</span> <span style="color: #008080;">or</span> <span style="color: #000000;">rhs</span>
     <span style="color: #008080;">elsif</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"xor"</span> <span style="color: #008080;">then</span>
         <span style="color: #008080;">return</span> <span style="color: #000000;">lhs</span> <span style="color: #008080;">xor</span> <span style="color: #000000;">rhs</span>
     <span style="color: #008080;">elsif</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"not"</span> <span style="color: #008080;">then</span>
         <span style="color: #008080;">return</span> <span style="color: #008080;">not</span> <span style="color: #000000;">rhs</span>
     <span style="color: #008080;">else</span>
         <span style="color: #0000FF;">?</span><span style="color: #000000;">9</span><span style="color: #0000FF;">/</span><span style="color: #000000;">0</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>

 <span style="color: #008080;">function</span> <span style="color: #000000;">next_comb</span><span style="color: #0000FF;">()</span>
     <span style="color: #004080;">integer</span> <span style="color: #000000;">fdx</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">flags</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">while</span> <span style="color: #000000;">flags</span><span style="color: #0000FF;">[</span><span style="color: #000000;">fdx</span><span style="color: #0000FF;">]=</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
         <span style="color: #000000;">flags</span><span style="color: #0000FF;">[</span><span style="color: #000000;">fdx</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
         <span style="color: #000000;">fdx</span> <span style="color: #0000FF;">-=</span> <span style="color: #000000;">1</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">fdx</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">2</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #004600;">false</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>  <span style="color: #000080;font-style:italic;">-- all done</span>
     <span style="color: #000000;">flags</span><span style="color: #0000FF;">[</span><span style="color: #000000;">fdx</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
     <span style="color: #008080;">return</span> <span style="color: #004600;">true</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>

 <span style="color: #008080;">procedure</span> <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">expr</span><span style="color: #0000FF;">)</span>
     <span style="color: #000000;">opstack</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
     <span style="color: #000000;">op</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
     <span style="color: #000000;">names</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #008000;">"false"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"true"</span><span style="color: #0000FF;">}</span>
     <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">expr</span>
     <span style="color: #000000;">sidx</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
     <span style="color: #000000;">nxtch</span><span style="color: #0000FF;">()</span>
     <span style="color: #000000;">get_token</span><span style="color: #0000FF;">()</span>
     <span style="color: #000000;">Expr</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">if</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #000000;">PopFactor</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">opstack</span><span style="color: #0000FF;">)!=</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">err</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"some error"</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #000000;">flags</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">names</span><span style="color: #0000FF;">))</span>
     <span style="color: #000000;">flags</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;">1</span> <span style="color: #000080;font-style:italic;">-- set "true" true</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;">"%s  %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #000000;">names</span><span style="color: #0000FF;">[</span><span style="color: #000000;">3</span><span style="color: #0000FF;">..$]),</span><span style="color: #000000;">s</span><span style="color: #0000FF;">})</span>
     <span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
         <span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">3</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">flags</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> <span style="color: #000080;font-style:italic;">-- (skipping true&false)</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;">"%s%s"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">fmt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">flags</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]),</span><span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #008000;">' '</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">names</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]))})</span>
         <span style="color: #008080;">end</span> <span style="color: #008080;">for</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;">" %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">fmt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">evaluate</span><span style="color: #0000FF;">(</span><span style="color: #000000;">opstack</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]))})</span>
         <span style="color: #008080;">if</span> <span style="color: #008080;">not</span> <span style="color: #000000;">next_comb</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
     <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\n"</span><span style="color: #0000FF;">)</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>

 <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"young and not (ugly or poor)"</span><span style="color: #0000FF;">)</span>
 <span style="color: #008080;">if</span> <span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()!=</span><span style="color: #004600;">JS</span> <span style="color: #008080;">then</span> <span style="color: #000080;font-style:italic;">-- (no gets(0) in a browser)</span>
     <span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
         <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"input expression:"</span><span style="color: #0000FF;">)</span>
         <span style="color: #004080;">string</span> <span style="color: #000000;">t</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">trim</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">gets</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">))</span>
         <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\n"</span><span style="color: #0000FF;">)</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">t</span><span style="color: #0000FF;">=</span><span style="color: #008000;">""</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">t</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
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