1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
|
<HTML>
<HEAD>
<!-- This HTML file has been created by texi2html 1.29
from ../tnf/nametutorial.tnf on 12 Febuary 2003 -->
<TITLE>Tutorial on Name Analysis - Classes with Multiple Inheritance</TITLE>
</HEAD>
<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#0000EE" VLINK="#551A8B" ALINK="#FF0000" BACKGROUND="gifs/bg.gif">
<TABLE BORDER=0 CELLSPACING=0 CELLPADDING=0" VALIGN=BOTTOM>
<TR VALIGN=BOTTOM>
<TD WIDTH="160" VALIGN=BOTTOM><IMG SRC="gifs/elilogo.gif" BORDER=0> </TD>
<TD WIDTH="25" VALIGN=BOTTOM><img src="gifs/empty.gif" WIDTH=25 HEIGHT=25></TD>
<TD ALIGN=LEFT WIDTH="600" VALIGN=BOTTOM><IMG SRC="gifs/title.gif"></TD>
</TR>
</TABLE>
<HR size=1 noshade width=785 align=left>
<TABLE BORDER=0 CELLSPACING=2 CELLPADDING=0>
<TR>
<TD VALIGN=TOP WIDTH="160">
<h4>General Information</h4>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="index.html">Eli: Translator Construction Made Easy</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="gindex_toc.html">Global Index</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="faq_toc.html" >Frequently Asked Questions</a> </td></tr>
</table>
<h4>Tutorials</h4>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="EliRefCard_toc.html">Quick Reference Card</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="novice_toc.html">Guide For new Eli Users</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="news_toc.html">Release Notes of Eli</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="nametutorial_toc.html">Tutorial on Name Analysis</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="typetutorial_toc.html">Tutorial on Type Analysis</a></td></tr>
</table>
<h4>Reference Manuals</h4>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="ui_toc.html">User Interface</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="pp_toc.html">Eli products and parameters</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="lidoref_toc.html">LIDO Reference Manual</a></td></tr>
</table>
<h4>Libraries</h4>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="lib_toc.html">Eli library routines</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="modlib_toc.html">Specification Module Library</a></td></tr>
</table>
<h4>Translation Tasks</h4>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="lex_toc.html">Lexical analysis specification</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="syntax_toc.html">Syntactic Analysis Manual</a></td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="comptrees_toc.html">Computation in Trees</a></td></tr>
</table>
<h4>Tools</h4>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="lcl_toc.html">LIGA Control Language</a> </td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="show_toc.html">Debugging Information for LIDO</a> </td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="gorto_toc.html">Graphical ORder TOol</a> </td></tr>
</table>
<p>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="fw_toc.html">FunnelWeb User's Manual</a> </td></tr>
</table>
<p>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="ptg_toc.html">Pattern-based Text Generator</a> </td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="deftbl_toc.html">Property Definition Language</a> </td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="oil_toc.html">Operator Identification Language</a> </td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="tp_toc.html">Tree Grammar Specification Language</a> </td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="clp_toc.html">Command Line Processing</a> </td></tr>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="cola_toc.html">COLA Options Reference Manual</a> </td></tr>
</table>
<p>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="idem_toc.html">Generating Unparsing Code</a> </td></tr>
</table>
<p>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="mon_toc.html">Monitoring a Processor's Execution</a> </td></tr>
</table>
<h4>Administration</h4>
<table BORDER=0 CELLSPACING=0 CELLPADDING=0>
<tr valign=top><td><img src="gifs/gelbekugel.gif" WIDTH=7 HEIGHT=7 ALT=" o"> </td><td><a href="sysadmin_toc.html">System Administration Guide</a> </td></tr>
</table>
<HR WIDTH="100%">
<CENTER> <A HREF="mailto:elibugs@cs.colorado.edu"><IMG SRC="gifs/button_mail.gif" NOSAVE BORDER=0 HEIGHT=32 WIDTH=32></A><A HREF="mailto:elibugs@cs.colorado.edu">Questions, Comments, ....</A></CENTER>
</TD>
<TD VALIGN=TOP WIDTH="25"><img src="gifs/empty.gif" WIDTH=25 HEIGHT=25></TD>
<TD VALIGN=TOP WIDTH="600">
<H1>Tutorial on Name Analysis</H1>
<P>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT=""><A HREF="nametutorial_9.html"><IMG SRC="gifs/prev.gif" ALT="Previous Chapter" BORDER="0"></A>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT=""><A HREF="nametutorial_11.html"><IMG SRC="gifs/next.gif" ALT="Next Chapter" BORDER="0"></A>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT=""><A HREF="nametutorial_toc.html"><IMG SRC="gifs/up.gif" ALT="Table of Contents" BORDER="0"></A>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT="">
<HR size=1 noshade width=600 align=left>
<H1><A NAME="SEC10" HREF="nametutorial_toc.html#SEC10">Classes with Multiple Inheritance</A></H1>
<P>
Our previous examples of modules and <CODE>with</CODE> statements can
be easily combined to demonstrate the scope rules for object
oriented classes with multiple inheritance.
<P>
To avoid confusion with the so far specified scope rules
we introduce a new language construct for declaration
of classes:
<P>
<B>Class.con</B>[28]==
<PRE>
<TT>
Declaration: 'class' DefIdent Inheritances ClassBlock ';'.
ClassBlock: Compound.
Inheritances: Inheritance*.
Inheritance: ':' InheritIdent.
InheritIdent: Ident.
</TT>
</PRE>
<FONT SIZE=1>
<PRE>
This macro is attached to a product file.
</PRE>
</FONT>
<P>
Applied identifier occurrences within the body of a class
are bound to definitions of that range, or to definitions
that are visible due to inheritances from other classes
(or modules), or to definitions in the ranges that enclose
the class declaration.
<P>
Hence, the scopes obtained from inheritances are inserted
into the environment hierarchy of the class body, as
in the case of our <CODE>with</CODE> statements.
<P>
Since classes that are used for inheritance may
inherit from other classes, the inheritance relation must form
a partial order. It must not be cyclic.
A class <CODE>c1</CODE> may inherit from a class <CODE>c2</CODE> via
several paths through the inheritance relation.
<P>
That partial order governs hiding of definitions:
A definition of an identifier <CODE>a</CODE> in the body of a class
<CODE>c</CODE> hides definitions of <CODE>a</CODE> in any class directly
or indirectly inherited by <CODE>c</CODE>.
<P>
Hence, the scope property of a class is the scope of the
class body embedded in the environment of the
inheritance relation for that class.
<P>
Wherever the class identifier is visible it can be used for
qualified access, as introduced for modules:
A qualified access <CODE>c::a</CODE> identifies an <CODE>a</CODE> defined
in the body of class <CODE>c</CODE> or in a class inherited by <CODE>c</CODE>
according to the inheritance relation.
<P>
These scope rules are specified using the techniques of the
last two examples:
A class has a scope property, as a module has; and
a class body inherits other scopes as our <CODE>with</CODE> statement
does. In this case there may be multiple scopes to be
inherited.
Hence, the <CODE>ClassBlock</CODE> combines the two roles
<CODE>RangeScopeProp</CODE> and <CODE>RangeMulInh</CODE> of the library module.
<P>
<B>Class.lido</B>[29]==
<PRE>
<TT>
SYMBOL ClassBlock INHERITS RangeScopeProp, RangeMulInh END;
RULE: Declaration ::= 'class' DefIdent Inheritances ClassBlock ';' COMPUTE
ClassBlock.ScopeKey = DefIdent.Key;
ClassBlock.GotInh = Inheritances CONSTITUENTS InheritIdent.InheritOk;
Inheritances.ToEnv = ClassBlock.Env;
END;
SYMBOL Inheritances: ToEnv: Environment;
</TT>
</PRE>
<FONT SIZE=1>
<PRE>
This macro is attached to a product file.
</PRE>
</FONT>
<P>
The <CODE>Inheritances</CODE> affect the scope of the class body,
like the <CODE>WithBody</CODE> in the example above.
As there may be several <CODE>Inheritances</CODE> the attribute
<CODE>Inheritances.ToEnv</CODE> is accessed from each.
The <CODE>InheritIdent</CODE> has the role <CODE>InheritScope</CODE> provided
by the library module for scope properties already used above.
It adds each single inheritance to the inheritance relation
of the class scope specified by <CODE>INCLUDING Inheritances.ToEnv</CODE>.
<P>
The role <CODE>InheritScope</CODE> yields an attribute <CODE>InheritOk</CODE>.
It indicates whether the inheritance relation is not cyclic.
It is used to issue an error message on violation.
<P>
<B>ClassInherit.lido</B>[30]==
<PRE>
<TT>
SYMBOL InheritIdent INHERITS
InheritScope, ChkModUseIdent,
IdUseEnv, ChkIdUse, IdentOcc
COMPUTE
SYNT.InnerScope = INCLUDING Inheritances.ToEnv;
SYNT.OuterScope = GetScope (THIS.Key, NoEnv)
<- INCLUDING RootScope.GotScopeProp;
IF (AND (NOT (THIS.InheritOk), NE (THIS.Key, NoKey)),
message (FATAL, CatStrInd ("cyclic inheritance: ", THIS.Sym),
0, COORDREF))
;
END;
</TT>
</PRE>
<FONT SIZE=1>
<PRE>
This macro is attached to a product file.
</PRE>
</FONT>
<P>
It has also to be checked that the <CODE>InheritIdent</CODE> is bound
to an object (class or module) that has a scope property.
The role <CODE>ChkModUseIdent</CODE> defined above is reused for that
purpose.
<P>
The library module for scope properties ensures that all relevant
inheritances are considered, all relevant scope properties are
associated, and all relevant definitions are encountered, before
applied identifier occurrences are bound in the class body or in
qualified accesses.
<P>
We now introduce an additional uniqueness requirement for inheritance:
If an applied identifier occurrence is bound to a definition
in an inherited environment there must not be a not hidden binding of
that identifier in another inherited environment.
Such an alternative binding is checked by <CODE>ChkInhIdUse</CODE> for
all <CODE>IdUseEnv</CODE> occurrences and by <CODE>ChkInhIdUseScopeProp</CODE>
for all <CODE>IdUseScopeProp</CODE> occurrences:
<P>
<B>UniqueInherit.lido</B>[31]==
<PRE>
<TT>
SYMBOL UseIdent INHERITS ChkInhIdUse END;
SYMBOL TypeUseIdent INHERITS ChkInhIdUse END;
SYMBOL QualIdent INHERITS ChkInhIdUseScopeProp END;
SYMBOL SelectIdent INHERITS ChkInhIdUseScopeProp END;
</TT>
</PRE>
<FONT SIZE=1>
<PRE>
This macro is attached to a product file.
</PRE>
</FONT>
<P>
<HR size=1 noshade width=600 align=left>
<P>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT=""><A HREF="nametutorial_9.html"><IMG SRC="gifs/prev.gif" ALT="Previous Chapter" BORDER="0"></A>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT=""><A HREF="nametutorial_11.html"><IMG SRC="gifs/next.gif" ALT="Next Chapter" BORDER="0"></A>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT=""><A HREF="nametutorial_toc.html"><IMG SRC="gifs/up.gif" ALT="Table of Contents" BORDER="0"></A>
<IMG SRC="gifs/empty.gif" WIDTH=25 HEIGHT=25 ALT="">
<HR size=1 noshade width=600 align=left>
</TD>
</TR>
</TABLE>
</BODY></HTML>
|
