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[[painless-lang-spec]]
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== Painless Language Specification
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Painless is a scripting language designed for security and performance.
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Painless syntax is similar to Java syntax along with some additional
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features such as dynamic typing, Map and List accessor shortcuts, and array
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initializers. As a direct comparison to Java, there are some important
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differences, especially related to the casting model. For more detailed
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conceptual information about the basic constructs that Painless and Java share,
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refer to the corresponding topics in the
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https://docs.oracle.com/javase/specs/jls/se8/html/index.html[Java Language
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Specification].
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Painless scripts are parsed and compiled using the http://www.antlr.org/[ANTLR4]
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and http://asm.ow2.org/[ASM] libraries. Scripts are compiled directly
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into Java Virtual Machine (JVM) byte code and executed against a standard JVM.
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This specification uses ANTLR4 grammar notation to describe the allowed syntax.
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However, the actual Painless grammar is more compact than what is shown here.
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2019-05-21 13:47:47 -04:00
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include::painless-lang-spec/index.asciidoc[]
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