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| <tr><td width=20><td><b>HOC(1)</b><td align=right><b>HOC(1)</b> |
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| <br> |
| <p><font size=+1><b>NAME </b></font><br> |
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| hoc – interactive floating point language<br> |
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| <p><font size=+1><b>SYNOPSIS </b></font><br> |
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| <tt><font size=+1>hoc</font></tt> [ <i>file ...</i> ] [ <tt><font size=+1>−e</font></tt> <i>expression</i> ]<br> |
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| <p><font size=+1><b>DESCRIPTION </b></font><br> |
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| <i>Hoc</i> interprets a simple language for floating point arithmetic, |
| at about the level of BASIC, with C-like syntax and functions. |
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| The named <i>files</i> are read and interpreted in order. If no <i>file</i> |
| is given or if <i>file</i> is <tt><font size=+1>−</font></tt> <i>hoc</i> interprets the standard input. The |
| <tt><font size=+1>−e</font></tt> option allows input to <i>hoc</i> to be specified on the command line, |
| to be treated as if it appeared in a file. |
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| <i>Hoc</i> input consists of <i>expressions</i> and <i>statements</i>. Expressions |
| are evaluated and their results printed. Statements, typically |
| assignments and function or procedure definitions, produce no |
| output unless they explicitly call <i>print</i>. |
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| Variable names have the usual syntax, including <tt><font size=+1>_</font></tt>; the name <tt><font size=+1>_</font></tt> |
| by itself contains the value of the last expression evaluated. |
| The variables <tt><font size=+1>E</font></tt>, <tt><font size=+1>PI</font></tt>, <tt><font size=+1>PHI</font></tt>, <tt><font size=+1>GAMMA</font></tt> and <tt><font size=+1>DEG</font></tt> are predefined; the last |
| is 59.25..., degrees per radian. |
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| Expressions are formed with these C-like operators, listed by |
| decreasing precedence.<br> |
| <tt><font size=+1>^</font></tt> exponentiation<br> |
| <tt><font size=+1>! − ++ −−<br> |
| * / %<br> |
| + −<br> |
| > >= < <= == !=<br> |
| &&<br> |
| ||<br> |
| = += −= *= /= %=<br> |
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| </font></tt> |
| Built in functions are <tt><font size=+1>abs</font></tt>, <tt><font size=+1>acos</font></tt>, <tt><font size=+1>asin</font></tt>, <tt><font size=+1>atan</font></tt> (one argument), <tt><font size=+1>cos</font></tt>, |
| <tt><font size=+1>cosh</font></tt>, <tt><font size=+1>exp</font></tt>, <tt><font size=+1>int</font></tt>, <tt><font size=+1>log</font></tt>, <tt><font size=+1>log10</font></tt>, <tt><font size=+1>sin</font></tt>, <tt><font size=+1>sinh</font></tt>, <tt><font size=+1>sqrt</font></tt>, <tt><font size=+1>tan</font></tt>, and <tt><font size=+1>tanh</font></tt>. The |
| function <tt><font size=+1>read(x)</font></tt> reads a value into the variable <tt><font size=+1>x</font></tt> and returns |
| 0 at EOF; the statement <tt><font size=+1>print</font></tt> prints a list of expressions that |
| may include string constants such as |
| <tt><font size=+1>"hello\n"</font></tt>. |
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| <tt><font size=+1> |
| </font></tt>Control flow statements are <tt><font size=+1>if</font></tt>-<tt><font size=+1>else</font></tt>, <tt><font size=+1>while</font></tt>, and <tt><font size=+1>for</font></tt>, with braces |
| for grouping. Newline ends a statement. Backslash-newline is equivalent |
| to a space. |
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| Functions and procedures are introduced by the words <tt><font size=+1>func</font></tt> and |
| <tt><font size=+1>proc</font></tt>; <tt><font size=+1>return</font></tt> is used to return with a value from a function.<br> |
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| </table> |
| <p><font size=+1><b>EXAMPLES </b></font><br> |
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| <tt><font size=+1>func gcd(a, b) {<br> |
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| temp = abs(a) % abs(b)<br> |
| if(temp == 0) return abs(b)<br> |
| return gcd(b, temp)<br> |
| |
| </table> |
| }<br> |
| for(i=1; i<12; i++) print gcd(i,12)<br> |
| </font></tt> |
| </table> |
| <p><font size=+1><b>SOURCE </b></font><br> |
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| <tt><font size=+1>/usr/local/plan9/src/cmd/hoc<br> |
| </font></tt> |
| </table> |
| <p><font size=+1><b>SEE ALSO </b></font><br> |
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| <a href="../man1/bc.html"><i>bc</i>(1)</a>, <a href="../man1/dc.html"><i>dc</i>(1)</a><br> |
| B. W. Kernighan and R. Pike, <i>The Unix Programming Environment,</i> |
| Prentice-Hall, 1984<br> |
| |
| </table> |
| <p><font size=+1><b>BUGS </b></font><br> |
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| Error recovery is imperfect within function and procedure definitions.<br> |
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