| author | Oleksandr Gavenko <gavenkoa@gmail.com> |
| Mon, 16 Sep 2019 22:13:19 +0300 | |
| changeset 2376 | 20b65f046002 |
| parent 2228 | 837f1337c59b |
| permissions | -rw-r--r-- |
|
1905
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
1 |
.. -*- coding: utf-8; -*- |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
2 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
3 |
===== |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
4 |
BNF |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
5 |
===== |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
6 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
7 |
What is BNF? |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
8 |
============ |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
9 |
.. contents:: |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
10 |
:local: |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
11 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
12 |
BNF is an acronym for "Backus Naur Form". John Backus and Peter Naur introduced |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
13 |
for the first time a formal notation to describe the syntax of a given language |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
14 |
(ALGOL 60 programming language). |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
15 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
16 |
See: :rfc:`2234`. |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
17 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
18 |
BNF syntax |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
19 |
========== |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
20 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
21 |
The meta-symbols of BNF are: |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
22 |
|
|
2228
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
23 |
``::=`` |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
24 |
Meaning "is defined as". |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
25 |
``|`` |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
26 |
Meaning "or". |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
27 |
``<``, ``>`` |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
28 |
Angle brackets used to surround category names (some times skipped). |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
29 |
``[``, ``]`` |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
30 |
Optional items are enclosed in. |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
31 |
``{``, ``}``
|
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
32 |
Repetitive items (zero or more times) are enclosed in. |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
33 |
``"abc..."`` |
|
837f1337c59b
Removed indentation that compiled into <blockquote>.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
1912
diff
changeset
|
34 |
Terminals are enclosed in to distinguish them from meta-symbols. |
|
1905
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
35 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
36 |
BNF in BNF |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
37 |
========== |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
38 |
:: |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
39 |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
40 |
syntax ::= { rule }
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
41 |
rule ::= identifier "::=" expression |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
42 |
expression ::= term { "|" term }
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
43 |
term ::= factor { factor }
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
44 |
factor ::= identifier | |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
45 |
quoted_symbol | |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
46 |
"(" expression ")" |
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
47 |
"[" expression "]" | |
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
48 |
"{" expression "}"
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
49 |
identifier ::= letter { letter | digit }
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
50 |
quoted_symbol ::= """ { any_character } """
|
|
fba288d59662
Include only local subsections into TOC. This prevent duplication of
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff
changeset
|
51 |