94 lines
2.4 KiB
Plaintext
94 lines
2.4 KiB
Plaintext
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[[literals]]
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=== Literals
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Literals are values that you can specify directly in Painless scripts.
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[[integers]]
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==== Integers
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Specify integer literals in decimal, octal, or hex notation. Use the following
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single letter designations to specify the primitive type: `l` for `long`, `f`
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for `float`, and `d` for `double`. If not specified, the type defaults to
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`int` (with the exception of certain assignments described later).
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*Grammar:*
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[source,ANTLR4]
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----
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INTEGER: '-'? ( '0' | [1-9] [0-9]* ) [lLfFdD]?;
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OCTAL: '-'? '0' [0-7]+ [lL]?;
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HEX: '-'? '0' [xX] [0-9a-fA-F]+ [lL]?;
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----
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*Examples:*
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[source,Java]
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----
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0 // integer literal of 0
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0D // double literal of 0.0
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1234L // long literal of 1234
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-90F // float literal of -90.0
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-022 // integer literal of -18 specified in octal
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0xF2A // integer literal of 3882
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----
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[[floating-point-values]]
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==== Floating Point Values
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Specify floating point literals using the following single letter designations
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for the primitive type: `f` for `float` and `d` for `double`.
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If not specified, the type defaults to `double`.
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*Grammar:*
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[source,ANTLR4]
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----
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DECIMAL: '-'? ( '0' | [1-9] [0-9]* ) (DOT [0-9]+)? ( [eE] [+\-]? [0-9]+ )? [fFdD]?;
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----
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*Examples:*
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[source,Java]
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----
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0.0 // double value of 0.0
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1E6 // double value of 1000000
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0.977777 // double value of 0.97777
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-126.34 // double value of -126.34
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89.9F // float value of 89.9
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----
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[[strings]]
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==== Strings
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Specify literal string with either single or double quotes. In double-quoted
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literal strings, you can escape double-quotes with a backslash to include them
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in the string. Similarly, you escape single quotes with a backslash in
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single-quoted literal strings. Backslashes themselves also need to be
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escaped with a backslash.
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*Grammar:*
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[source,ANTLR4]
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----
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STRING: ( '"' ( '\\"' | '\\\\' | ~[\\"] )*? '"' ) | ( '\'' ( '\\\'' | '\\\\' | ~[\\'] )*? '\'' );
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----
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*Examples:*
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[source,Java]
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----
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"double-quoted String literal"
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'single-quoted String literal'
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"\"double-quoted String with escaped double-quotes\" and backslash: \\"
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'\'single-quoted String with escaped single-quotes\' and backslash \\'
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"double-quoted String with non-escaped 'single-quotes'"
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'single-quoted String with non-escaped "double-quotes"'
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----
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[[char]]
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===== Char
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You cannot directly specify character literals in Painless. However, you can
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cast single-character strings to char. Attempting to cast a multi-character
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string to a char throws an error.
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*Examples:*
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[source,Java]
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----
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(char)"C"
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(char)'c'
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----
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