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Import AnaGram (near-)release tree into Mercurial.
author David A. Holland
date Sat, 22 Dec 2007 17:52:45 -0500
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1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
2 <HTML>
3 <HEAD>
4 <TITLE>Four Function Calculator</TITLE>
5 </HEAD>
6
7
8 <BODY BGCOLOR="#ffffff" BACKGROUND="tilbl6h.gif"
9 TEXT="#000000" LINK="#0033CC"
10 VLINK="#CC0033" ALINK="#CC0099">
11
12 <P>
13 <IMG ALIGN="right" SRC="../images/agrsl6c.gif" ALT="AnaGram"
14 WIDTH=124 HEIGHT=30 >
15 <BR CLEAR="all">
16 Back to <A HREF="../index.html">Index</A>
17 <P>
18 <IMG ALIGN="bottom" SRC="../images/rbline6j.gif" ALT="----------------------"
19 WIDTH=1010 HEIGHT=2 >
20 <P>
21
22 <H1>Four Function Calculator</H1>
23
24 <IMG ALIGN="bottom" SRC="../images/rbline6j.gif" ALT="----------------------"
25 WIDTH=1010 HEIGHT=2 >
26 <P>
27 <H2>Introduction</H2>
28 <P>
29 <tt>ffcalc.syn</tt> implements a simple four function
30 calculator. The
31 calculator has 52 registers, labeled 'a' through 'z' and 'A'
32 through 'Z'. <tt>ffcalc</tt> evaluates arithmetic expressions and
33 assignment statements and prints the results. The
34 expressions may contain '<CODE>+</CODE>', '<CODE>-</CODE>',
35 '<CODE>*</CODE>', and '<CODE>/</CODE>' operators as
36 well as parentheses. In addition, <tt>ffcalc</tt> supports
37 the free
38 use of white space and C style comments in the input. It
39 also includes syntax error handling, including a diagnostic
40 message, and resynchronization.
41 <P>
42 <tt>ffcalcmx.syn</tt> is a simple variation on
43 <tt>ffcalc.syn</tt>. The only
44 difference between the two grammars is that <tt>ffcalcx</tt> uses a
45 deliberately ambiguous grammar for expressions, with
46 precedence statements to resolve the ambiguities.
47 <P>
48
49 <H2>Building FFCALC</H2>
50 To build a working copy of <tt>ffcalc</tt>, you need to
51 carry out the following steps:
52 <UL>
53 <LI> 1. Run Anagram and build a parser for <tt>ffcalc.syn</tt>. </LI>
54 <LI> 2. Using your C compiler, compile and link <tt>ffcalc.c</tt>. </LI>
55 </UL>
56 <P>
57
58 <H2>Running FFCALC</H2>
59 <tt>ffcalc</tt> reads expressions and assignment statements from
60 stdin. You may either type input directly, or provide input
61 by using file redirection. The file <tt>test.ffc</tt> has been
62 provided as a sample.
63 <P>
64 Run <tt>ffcalc</tt> from the command line and type an
65 arithmetic expression or assignment
66 statement to be evaluated. <tt>ffcalc</tt> will accept addition,
67 subtraction, multiplication and division operations, as well
68 as unary negation, using floating point arithmetic. It
69 respects the conventional order of operations and allows the
70 use of parentheses to override the natural order of
71 computation. You may use spaces, tabs, and C-style comments
72 freely. You may use variable names consisting of a single
73 upper or lower case letter.
74 <P>
75 Each expression or assignment statement must be terminated
76 by a newline. Note that <tt>ffcalc</tt>, unlike
77 <tt>rcalc</tt>, does not explicitly check
78 for division by zero.
79 </P>
80
81 <BR>
82
83 <IMG ALIGN="bottom" SRC="../images/rbline6j.gif" ALT="----------------------"
84 WIDTH=1010 HEIGHT=2 >
85 <P>
86 <IMG ALIGN="right" SRC="../images/pslrb6d.gif" ALT="Parsifal Software"
87 WIDTH=181 HEIGHT=25>
88 <BR CLEAR="right">
89 <P>
90 Back to <A HREF="../index.html">Index</A>
91 <P>
92 <ADDRESS><FONT SIZE="-1">
93 AnaGram parser generator - examples<BR>
94 Four Function Calculator<BR>
95 Copyright &copy; 1993-1999, Parsifal Software. <BR>
96 All Rights Reserved.<BR>
97 </FONT></ADDRESS>
98
99 </BODY>
100 </HTML>
101