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authorFrancesco Potortì2002-07-02 11:54:32 +0000
committerFrancesco Potortì2002-07-02 11:54:32 +0000
commit1038941db1cf4c2345a7b2e5e1f6a182615bfa1a (patch)
tree69684192984fd5d40a38bce579ed7212708faa84
parent005e1610198130bdca78577a3e9608716a4aac06 (diff)
downloademacs-1038941db1cf4c2345a7b2e5e1f6a182615bfa1a.tar.gz
emacs-1038941db1cf4c2345a7b2e5e1f6a182615bfa1a.zip
Back to the old explanation, which was more concise, with just the first
two lines changed.
-rw-r--r--etc/ETAGS.EBNF24
1 files changed, 12 insertions, 12 deletions
diff --git a/etc/ETAGS.EBNF b/etc/ETAGS.EBNF
index d2f8b68297e..195eba67325 100644
--- a/etc/ETAGS.EBNF
+++ b/etc/ETAGS.EBNF
@@ -1,7 +1,9 @@
1-*- indented-text -*-
2
1This file contains two sections: 3This file contains two sections:
2 4
31) An EBNF (Extended Backus Normal Form) description of the format of 51) An EBNF (Extended Backus Normal Form) description of the format of
4 the tags file created by etags.c and interpreted by etags.el 6 the tags file created by etags.c and interpreted by etags.el
52) A discussion of tag names and implicit tag names 72) A discussion of tag names and implicit tag names
6 8
7======================= EBNF tag file description ======================= 9======================= EBNF tag file description =======================
@@ -56,7 +58,7 @@ realposition ::= "," unsint | unsint "," | unsint "," unsint
56 58
57 59
58 60
59======================== discussion on tag names ========================= 61======================== discussion of tag names =========================
60 62
61- What are tag names 63- What are tag names
62Tag lines in a tags file are usually made from the above defined pattern 64Tag lines in a tags file are usually made from the above defined pattern
@@ -72,16 +74,14 @@ Emacs can find a tag faster and more accurately. These tag names are
72part of tag lines in the tags file, so we call them "explicit". 74part of tag lines in the tags file, so we call them "explicit".
73 75
74- Why implicit tag names are even better 76- Why implicit tag names are even better
75Often tag names are redundant; this happens when the name of a tag is an 77When a tag line has no name, but a name can be deduced from the pattern,
76easily guessable substring of the tag pattern. We define a set of rules 78we say that the tag line has an implicit tag name. etags.c uses
77to decide whether it is possible to deduce the tag name from the pattern, 79implicit tag names when possible, in order to reduce the number of
78and make an unnamed tag in those cases. The name deduced from the 80explicit tag names in a tags file, thus reducing the size of the tags
79pattern of an unnamed tag is the implicit name of that tag. The use of 81file. When the user looks for a tag, and Emacs founds no explicit tag
80implicit tag names reduces the size of the tags file. When the user 82names that match it, Emacs then tries to match the tag with an implicit
81looks for a tag, and Emacs founds no explicit tag names that match it, 83tag name. Such a match occurs when the tag matches a pattern, subject
82Emacs then tries to match the tag with an implicit tag name. Such a 84to the satisfaction of all the following four rules:
83match occurs when the tag matches a pattern, subject to the satisfaction
84of all the following four rules:
85 85
86 NONAM=" \f\t\n\r()=,;"; 86 NONAM=" \f\t\n\r()=,;";
87 1. the tag does not contain any of the characters in NONAM; 87 1. the tag does not contain any of the characters in NONAM;