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<?xml version="1.0"?>
<!--
Copyright 2000-2004 The Apache Software Foundation
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<document>
<properties>
<title>Velocity Specification - BNF</title>
<author email="jon@latchkey.com">Velocity Documentation Team</author>
</properties>
<body>
<section name="Velocity Specification - BNF">
<p>
Please note that this is currently out of date and will be updated soon.
</p>
<source><![CDATA[
This is a tentative BNF for Velocity, right now this is
pretty much the WM syntax. This might change, as arithmetic
might not make it into the syntax, and the future
velocity syntax will more then likely remove block
markers and instead use an "#end" token to signify
the end of a directive.
<statement>
::= <text>
| <block>
| <if-statement>
| <else-if-statement>
| <foreach-statement>
| <include-statement>
| <set-statement>
| <parse-statement>
| <param-statment>
| <stop-statement>
| <reference>
<block>
::= "#begin" { <expresion> } "#end"
<if-statement>
::= "#if" "(" <expresion> ")" <statement> [ <else-statement> ]
<else-if-statement>
::= "#elseif" "(" <expresion> ")" <statement> [ <else-statement> ]
<foreach-statement>
::= "#foreach" <reference> "in" <reference> <statement>
<include-statement>
::= "#include" <string-literal>
<set-statement>
::= "#set" <reference> "=" <expression>
<parse-statement>
::= "#parse" <string-literal>
<param-statment>
::= "#param" <reference> "=" <string-literal>
<stop-statement>
::= "#stop"
<reference>
::= "$" <identifier> { "." <method> | <identifier> }
<method>
::= <identifier> "(" [ <parameter> { "," <parameter> } ] ")"
<parameter>
::= <reference> | <string-literal>
<alpha-char>
::= "a..z, A..Z"
<identifier-char>
::= "a..z, A..Z ,0..9 ,- ,_"
<identifier>
::= <alpha-char> { <identifier-char> }
<expression>
::= <true>
| <false>
| <primary-expression> "=" <assignment>
| <conditional-or-expression>
<assignment>
::= <primary-expression> "=" <assignment>
<conditional-or-expression>
::= <conditional-and-expression> { "||" <conditional-and-expression> }
<conditional-and-expression>
::= <equality-expression> { "&&" <equality-expression> }
<equality-expression>
::= <relational-expression>
{ "==" <relational-expression>
| "!=" <relational-expression>
}
<relational-expression>
::= <additive-expression>
{
"<" <additive-expression>
| ">" <additive-expression>
| "<=" <additive-expression>
| ">=" <additive-expression>
}
<additive-expression>
::= <multiplicative-expression>
{
"+" <multiplicative-expression>
| "-" <multiplicative-expression>
}
<multiplicative-expression>
::= <unary-expression>
{
"*" <unary-expression>
| "/" <unary-expression>
| "%" <unary-expression>
}
<unary-expression>
::= "!" <unary-expression> | <primary-expression>
<primary-expression>
::= <string-literal>
| <number-literal>
| <reference>
| "(" <expression> ")"
]]></source>
</section>
</body>
</document>
|
