opprec-table.sgml

Shall高级编程

      <table>
	<title>Operator Precedence</title>
	<tgroup cols="3">
	  <thead>
	    <row>
	      <entry>Operator</entry>
	      <entry>Meaning</entry>
	      <entry>Comments</entry>
	    </row>
	  </thead>
	  <tbody>
	    <row>
	      <entry><option></option></entry>
	      <entry></entry>
	      <entry><command>HIGHEST PRECEDENCE</command></entry>
	    </row>
	    <row>
	      <entry><option>var++ var--</option></entry>
	      <entry>post-increment, post-decrement</entry>
	      <entry><link linkend="cstyle">C-style</link> operators</entry>
	    </row>
	    <row>
	      <entry><option>++var --var</option></entry>
	      <entry>pre-increment, pre-decrement</entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>! ~</option></entry>
	      <entry><link linkend="notref">negation</link></entry>
	      <entry>logical / bitwise, inverts sense of following
	        operator</entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>**</option></entry>
	      <entry><link
	        linkend="exponentiationref">exponentiation</link></entry>
	      <entry><link linkend="arops1">arithmetic
	        operation</link></entry>
	    </row>
	    <row>
	      <entry><option>* / %</option></entry>
	      <entry>multiplication, division, modulo</entry>
	      <entry>arithmetic operation</entry>
	    </row>
	    <row>
	      <entry><option>+ -</option></entry>
	      <entry>addition, subtraction</entry>
	      <entry>arithmetic operation</entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>&lt;&lt; &gt;&gt;</option></entry>
	      <entry>left, right shift</entry>
	      <entry><link linkend="bitwsops1">bitwise</link></entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>-z -n</option></entry>
	      <entry><firstterm>unary</firstterm> comparison</entry>
	      <entry>string is/is-not <firstterm>null</firstterm></entry>
	    </row>
	    <row>
	      <entry><option>-e -f -t -x, etc.</option></entry>
	      <entry><firstterm>unary</firstterm> comparison</entry>
	      <entry><firstterm>files</firstterm></entry>
	    </row>
	    <row>
	      <entry><option>&lt; -lt &gt; -gt &lt;= -le &gt;= -ge</option></entry>
	      <entry><firstterm>compound</firstterm> comparison</entry>
	      <entry>string and integer</entry>
	    </row>
	    <row>
	      <entry><option>-nt -ot -ef</option></entry>
	      <entry><firstterm>compound</firstterm> comparison</entry>
	      <entry><firstterm>files</firstterm></entry>
	    </row>
	    <row>
	      <entry><option>== -eq != -ne</option></entry>
	      <entry>equality / inequality</entry>
	      <entry>test operators, string and integer</entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>&amp;</option></entry>
	      <entry>AND</entry>
	      <entry>bitwise</entry>
	    </row>
	    <row>
	      <entry><option>^</option></entry>
	      <entry>XOR</entry>
	      <entry><firstterm>exclusive</firstterm> OR, bitwise</entry>
	    </row>
	    <row>
	      <entry><option>|</option></entry>
	      <entry>OR</entry>
	      <entry>bitwise</entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>&amp;&amp; -a</option></entry>
	      <entry>AND</entry>
	      <entry>logical, <firstterm>compound</firstterm>
	        comparison</entry>
	    </row>
	    <row>
	      <entry><option>|| -o</option></entry>
	      <entry>OR</entry>
	      <entry>logical, <firstterm>compound</firstterm>
	        comparison</entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>?:</option></entry>
	      <entry><link linkend="cstrinary">trinary
	        operator</link></entry>
	      <entry>C-style</entry>
	    </row>
	    <row>
	      <entry><option>=</option></entry>
	      <entry><link linkend="eqref">assignment</link></entry>
	      <entry>(do not confuse with equality
	        <firstterm>test</firstterm>)</entry>
	    </row>
	    <row>
	      <entry><option>*= /= %= += -= &lt;&lt;= &gt;&gt;= &amp;= !=</option></entry>
	      <entry><link linkend="arithopscomb">combination
	        assignment</link></entry>
	      <entry>times-equal, divide-equal, mod-equal, etc.</entry>
	    </row>
	    <row>
	      <entry></entry>
	      <entry></entry>
	      <entry></entry>
	    </row>
	    <row>
	      <entry><option>,</option></entry>
	      <entry><link linkend="commaop">comma</link></entry>
	      <entry>links a sequence of operations</entry>
	    </row>
	    <row>
	      <entry><option></option></entry>
	      <entry></entry>
	      <entry><command>LOWEST PRECEDENCE</command></entry>
	    </row>
	  </tbody>
	</tgroup>
      </table>