38 lines
1.8 KiB
HTML
38 lines
1.8 KiB
HTML
<HTML><HEAD><TITLE>Tk Built-In Commands - report-error manual page</TITLE></HEAD>
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<BODY bgcolor = #c3ffc3>
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<H2><IMG ALIGN=BOTTOM SRC="./Img/ManPageGreen.gif"> report-error</H2>
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<I>Command invoked to process errors</I><P><IMG ALIGN=TOP SRC="./Img/line-red.gif">
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<H3><A NAME="M2">SYNOPSIS</A></H3>
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(<B>report-error </B><I>head message obj</I>)<BR>
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<H3><A NAME="M3">DESCRIPTION</A></H3>
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<B>Report-error</B> is called by the interpreter when an error occurs.
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This procedure is written in Scheme and can be by an application which
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needs to handle redefined to handle errors. The <I>head</I> argument is
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a string which identify the kind of error. The <I>head</I> argument
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contains the error message and <I>obj</I> contains the object which
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causes the error (or the empty list when there is no object to incriminate).
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<P>
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The STk library includes a default <B>report-error</B> procedure
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that posts a dialog box containing the error message and offers
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the user a chance to see a stack trace showing where the
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error occurred and its associated environment..
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<P>
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If an error occurs while is <B>report-error</B> execution, the
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interpreter detect that the procedure is buggy and it redirect further
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messages on the standard error port.
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<P>
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Hereafter is a simple non-graphical error reporter.
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<PRE>(define (report-error head message obj)
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(let ((port (current-error-port)))
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;; Display message
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(format port "~A: ~A ~S\n\n" head message obj)
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;; Display stack
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(let ((stack (%get-eval-stack))
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(env (%get-environment-stack)))
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(for-each (lambda (x y) (format port "~A ~A\n" x (uncode y)))
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env
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stack))))</PRE>
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<P><IMG ALIGN=TOP SRC="./Img/line-red.gif">
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<A HREF=./STk-hlp.html><IMG ALIGN=BOTTOM SRC="./Img/RefBookGreen.gif"> Back to the <B>STk</B> main page</A>
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</BODY></HTML>
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