87 lines
3.2 KiB
HTML
87 lines
3.2 KiB
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<!-- This file has been generated by unroff 1.0, 03/21/96 19:29:47. -->
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<!-- Do not edit! -->
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<link rev="made" href="mailto:net@informatik.uni-bremen.de">
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<title>unroff Programmer's Manual, section 13.</title>
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</head><body>
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<h2><a name="section13">13.</a> <tt> </tt>Miscellaneous Primitives
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</h2>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>The first two primitives described in this section are not essential,
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as the same function could be achieved with pipe streams,
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although with greater overhead.<tt> </tt>
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The remaining primitives perform a number of troff-specific operations
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and are only useful in a few specialized contexts.<tt> </tt>
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<h2>
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(shell-command <i>command</i>)
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</h2>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>Runs the specified
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<i>command
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</i>(which must be a string) as a shell command by passing it to a call to
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<i>system</i>(3).<tt> </tt>
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The return value is that of
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<i>system()
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</i>(an integer).<tt> </tt>
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<h2>
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(remove-file <i>filename</i>)
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</h2>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>Removes the specified file;
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<i>filename
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</i>must be a string or a symbol.<tt> </tt>
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<h2>
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(troff-compatible?)
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</h2>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>This predicate returns #t if troff compatibility mode has been
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enabled (i.e. if the option
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<b>-C
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</b>has been given), otherwise #f.<tt> </tt>
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<h2>
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(set-escape! <i>char</i>)
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</h2>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>Sets the troff escape character (initially `\') to the specified
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character argument.<tt> </tt>
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This primitive is used to implement the ``.ec'' request.<tt> </tt>
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<h2>
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<a name=".filter-eqn-line">(filter-eqn-line <i>string</i>)</a></h2>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>This primitive scans the string argument (which is supposed to
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be passed to the
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<i>eqn
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</i>preprocessor afterwards) for occurrences of the ``delim'' directive.<tt> </tt>
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If a ``delim'' directive is found, the current inline equation
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delimiters maintained by the parser are changed or disabled as specified by
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the directive.<tt> </tt>
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The primitive returns #f if
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<i>string
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</i>is empty or consists just of white space, or if it contains
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a valid ``delim'' or ``define'' directive, otherwise #t.<tt> </tt>
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The inline equation delimiters are disabled initially.<tt> </tt>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>The primitive is supposed to be used by implementations of
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the request ``.EQ'' and inline equation event handlers to intercept the
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<i>eqn
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</i>input.<tt> </tt>
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In this case, the
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<i>eqn
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</i>preprocessor need only be invoked if
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<i>filter-eqn-line
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</i>returned #t at least once.<tt> </tt>
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<h2>
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(skip-group)
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</h2>
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<p>
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 <tt> </tt> <tt> </tt> <tt> </tt>This primitive reads input lines from the current input stream
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and scans them for the escape sequences `\{' and `\}' until
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the nesting level of conditional input is balanced (i.e. until
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a matching closing brace for an initial opening brace has been found).<tt> </tt>
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The primitive is only useful for the implementation of the
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troff requests for conditional input.<tt> </tt>
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<p><hr>
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Markup created by <em>unroff</em> 1.0, <tt> </tt> <tt> </tt>March 21, 1996, <tt> </tt> <tt> </tt>net@informatik.uni-bremen.de</body>
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</html>
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