Parsing/Shunting-yard algorithm: Difference between revisions
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=={{header|Phix}}==
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<!--<lang Phix>
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #004080;">bool</span> <span style="color: #000000;">show_workings</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">true</span>
<span style="color: #008080;">constant</span> <span style="color: #000000;">operators</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #008000;">"^"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"*"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"/"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"+"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"-"</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: #000000;">4</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">2</span> <span style="color: #0000FF;">}</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">infix</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">rpn</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">sep</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">stack_top</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">stack</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{},</span>
<span style="color: #000000;">ops</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">split</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">substitute_all</span><span style="color: #0000FF;">(</span><span style="color: #000000;">infix</span><span style="color: #0000FF;">,{</span><span style="color: #008000;">"("</span><span style="color: #0000FF;">,</span><span style="color: #008000;">")"</span><span style="color: #0000FF;">},{</span><span style="color: #008000;">" ( "</span><span style="color: #0000FF;">,</span><span style="color: #008000;">" ) "</span><span style="color: #0000FF;">}),</span><span style="color: #008000;">' '</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;">"Infix input: %-32s%s"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">infix</span><span style="color: #0000FF;">,</span><span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">show_workings</span><span style="color: #0000FF;">?</span><span style="color: #008000;">'\n'</span><span style="color: #0000FF;">:</span><span style="color: #008000;">' '</span><span style="color: #0000FF;">)})</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: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">ops</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">op</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">ops</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</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;">"("</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">stack</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">stack</span><span style="color: #0000FF;">,</span><span style="color: #000000;">op</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">elsif</span> <span style="color: #000000;">op</span><span style="color: #0000FF;">=</span><span style="color: #008000;">")"</span> <span style="color: #008080;">then</span>
<span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">stack_top</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">stack</span><span style="color: #0000FF;">[$]</span>
<span style="color: #000000;">stack</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">stack</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..$-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">stack_top</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;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">sep</span><span style="color: #0000FF;">&</span><span style="color: #000000;">stack_top</span>
<span style="color: #000000;">sep</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">" "</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<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;">op</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: #004080;">integer</span> <span style="color: #000000;">prec</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;">while</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">stack</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">stack_top</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">stack</span><span style="color: #0000FF;">[$]</span>
<span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">stack_top</span><span style="color: #0000FF;">,</span><span style="color: #000000;">operators</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">or</span> <span style="color: #000000;">prec</span><span style="color: #0000FF;">></span><span style="color: #000000;">precedence</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">or</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">prec</span><span style="color: #0000FF;">=</span><span style="color: #000000;">precedence</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">and</span> <span style="color: #000000;">stack_top</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"^"</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">stack</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">stack</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..$-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">sep</span><span style="color: #0000FF;">&</span><span style="color: #000000;">stack_top</span>
<span style="color: #000000;">sep</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">" "</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #000000;">stack</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">stack</span><span style="color: #0000FF;">,</span><span style="color: #000000;">op</span><span style="color: #0000FF;">)</span>
<span
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">sep</span><span style="color: #0000FF;">&</span><span style="color: #000000;">op</span>
<span style="color: #000000;">sep</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">" "</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">show_workings</span> <span style="color: #008080;">then</span>
<span style="color: #0000FF;">?{</span><span style="color: #000000;">op</span><span style="color: #0000FF;">,</span><span style="color: #000000;">stack</span><span style="color: #0000FF;">,</span><span style="color: #000000;">res</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;">for</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">stack</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">to</span> <span style="color: #000000;">1</span> <span style="color: #008080;">by</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">op</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">stack</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span>
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">sep</span><span style="color: #0000FF;">&</span><span style="color: #000000;">op</span>
<span style="color: #000000;">sep</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">" "</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;">"result: %-22s [%s]\n"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">=</span><span style="color: #000000;">rpn</span><span style="color: #0000FF;">?</span><span style="color: #008000;">"ok"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"**ERROR**"</span><span style="color: #0000FF;">)})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"3 + 4 * 2 / (1 - 5) ^ 2 ^ 3"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"3 4 2 * 1 5 - 2 3 ^ ^ / +"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">show_workings</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"((1 + 2) ^ (3 + 4)) ^ (5 + 6)"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 + 3 4 + ^ 5 6 + ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(1 + 2) ^ (3 + 4) ^ (5 + 6)"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 + 3 4 + 5 6 + ^ ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"((3 ^ 4) ^ 2 ^ 9) ^ 2 ^ 5"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"3 4 ^ 2 9 ^ ^ 2 5 ^ ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(1 + 4) * (5 + 3) * 2 * 3"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 4 + 5 3 + * 2 * 3 *"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1 * 2 * 3 * 4"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 * 3 * 4 *"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1 + 2 + 3 + 4"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 + 3 + 4 +"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(1 + 2) ^ (3 + 4)"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 + 3 4 + ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(5 ^ 6) ^ 7"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"5 6 ^ 7 ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"5 ^ 4 ^ 3 ^ 2"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"5 4 3 2 ^ ^ ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1 + 2 + 3"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 + 3 +"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1 ^ 2 ^ 3"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 3 ^ ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(1 ^ 2) ^ 3"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 ^ 3 ^"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1 - 1 + 3"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 1 - 3 +"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"3 + 1 - 1"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"3 1 + 1 -"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1 - (2 + 3)"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"1 2 3 + -"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"4 + 3 + 2"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"4 3 + 2 +"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"5 + 4 + 3 + 2"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"5 4 + 3 + 2 +"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"5 * 4 * 3 * 2"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"5 4 * 3 * 2 *"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"5 + 4 - (3 + 2)"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"5 4 + 3 2 + -"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"3 - 4 * 5"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"3 4 5 * -"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"3 * (4 - 5)"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"3 4 5 - *"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(3 - 4) * 5"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"3 4 - 5 *"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"4 * 2 + 1 - 5"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"4 2 * 1 + 5 -"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">shunting_yard</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"4 * 2 / (1 - 5) ^ 2"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"4 2 * 1 5 - 2 ^ /"</span><span style="color: #0000FF;">)</span>
<!--</lang>-->
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